Assisted Migration (Assisted Colonization, Managed Relocation, Translocation, Helping Forests Walk) and Rewilding of Plants and Animals in an Era of Rapid Climate Change

EDITOR'S NOTE (by Connie Barlow): This annotated and linked list of online-accessible papers, articles, and news reports on assisted migration (aka: assisted colonization/colonisation, translocation, managed relocation, facilitated migration, neo-natives, helping forests walk, and climate-driven species redistribution) aims to further professional and popular understanding of the substance and history of debate and actions regarding one of the most significant developments in conservation biology, forestry, and natural resources management. This lengthy list is continually updated; entries are ordered by topic, with longer excerpts given for papers of high academic importance, insight into shifting conservation values, expansive treatment of the issue, and provision of background understanding.

The TERMINOLOGY DEBATE ramped up in 2008, when a multi-author paper advocated for a shift from the original (2004) term, assisted migration, to a new term, assisted colonization. In 2009 managed relocation was introduced and advocated as preferred terminology by conservation biologists and academics in ecological restoration. Facilitated migration was introduced by Canadian forestry professor Sally Aitken in 2008, but assisted migration has overwhelmingly remained the term of choice in that profession — although later nuanced as a tripartite: assisted population migration (seed transfer zones), assisted range expansion (poleward), and assisted species migration or assisted long-distance migration for glacial relicts (case study is Florida Torreya) and even widespread trees that greatly lag behind climate change (e.g., Whitebark Pine). Failure to move in sync with climate change is amplified in the Rocky Mountain and Great Basin regions of North America, where species that are documented as moving upslope are nonetheless dooming themselves: once upslope, they have cut off any natural ability for moving poleward instead, owing to their inability to survive the necessary descent by which to alter their course. A separate webpage that lists, links, and annotates the papers entailing the HISTORY OF THE TERMINOLOGY DEBATE is available here:

"Assisted Migration or Assisted Colonization: What's In a Name?" - updated in 2021 to include a new section:
"Decolonizing Scientific Language". Several papers by Australians called out "colonization" as an offensive term to aboriginal peoples. Meanwhile, a North American indigenous phrasing (possibly originating through Robin Wall Kimmerer, Potawatomi) emerged: "Helping Forests Walk"

NOTE: The volunteer editor and webmaster of this page of annotated scholarly links, Connie Barlow, founded Torreya Guardians in 2004 and initiated an assisted migration series on youtube in 2014: VIDEOS: "Climate, Trees, and Legacy"). In 2021 she retitled her lead video playlist, "Helping Forests Walk".


The FORESTRY section differs from the CONSERVATION BIOLOGY section in this now extremely lengthy webpage of annotated scholarly links. The reason is this: Foresters are accustomed to "managing" landscapes, so there has been little debate about whether to engage in assisted migration (especially of seed transfer guidelines). Rather, the focus is on species-by-species details of how to accomplish it.

WIKIPEDIA: "Assisted Migration of Forests in North America"

For readers focused on forestry in North America, the above wikipedia page is a superb overview in narrative style, with the most important news and scholarly links.

For an annotated list style (with excerpts) of the key papers (less attention to news), go directly to the FORESTRY TABLE OF CONTENTS.

Click to advance to each theme (or do an internal "Find" for a topic or year of your choice).

  • Key Charts and Papers (short list for all to begin here)
  • Society, Values, and Communications (incl. Science & Society field)
  • Ethics, Law, and History
  • Urban Ecology Assisted Migration (emphasis on trees)
  • Paleoecology, Paleobiology, and Biogeography (focus on Pleistocene range shifts as guidance for assisted migration)
  • Conservation Biology Assisted Colonization (this is a lengthy section)
  • Vertebrate Assisted Migration / Translocation
  • Pleistocene Rewilding and Taxon Substitution for Ecological Restoration

  • 2007 "Assisted Migration" debate begins in earnest
    Intermediate years papers are too many to list; search by internally by key words or year.
  • 2016 articles and papers
  • 2017 articles and papers
  • 2018 articles and papers
  • 2019 articles and papers
  • 2020 articles and papers
  • 2021 articles and papers
  • 2022 articles and papers
  • 2023 articles and papers
  • 2024 articles and papers

  • FORESTRY Assisted Migration / "Helping Forests Walk" (focus on North America; this is a very lengthy section).
    KEY REVIEW ARTICLES in forestry    • Paleoecology Specific to Forestry
          • Superb Overviews for students, activists, journalists, and foresters
          • Canada    • Europe     • USA    • Mexico
          • Maps of USA Tree Species Future Ranges (US Forest Service: 76 species western USA / 134 species eastern)
          • Details on tree range projection maps and model parameters
          • MapleSpruceLarchDouglas Fir & Ponderosa PineYellow CedarBlack Ash
          • Brewer SpruceRedwood + SequoiaArizona CypressJoshua TreeChestnutMagnolia sp.
          • AspenWhite PineOyamel FirBristlecone and Limber PineValley Oak
          • Note: WHITEBARK PINE has so many studies, do an internal "find" for that species.

  • Inadvertent Assisted Migration - documentation of poleward naturalization of native plants originating from horticultural plantings in the USA and Canada: This subsection was added in 2020. Species include: Magnolia, Pawpaw, Florida Torreya, Coast Redwood.

  • Inspiration: classic 30-minute allegorical tale, VIDEO: "The Man Who Planted Trees" (by Jean Giono, 1953)

    * * * * *

    OVERVIEW of how the "Assisted Migration" concept and practice has evolved
    Connie Barlow

    I initiated this annotated scholarly links webpage in 2007, when journalist Douglas Fox published in Conservation Magazine a cover story: "When World's Collide". Our citizen-led assisted migration actions of Torreya Guardians was the introductory example in that article, but our effort was presented as just the preview of what would follow as climate change pressed on. Nearly simultaneously, the New York Times posted a story by science writer Carl Zimmer: "A Radical Step to Preserve Species: Assisted Migration". Then in April 2007, the journal Conservation Biology published a paper by Jason S. McLachlan, Jessica J. Hellmann, and Mark W. Schwartz titled, "A Framework for Debate of Assisted Migration in an Era of Climate Change". The first two paragraphs of this now-classic and much-cited paper (as of this writing, 2021) focused on the stated intent and actions of Torreya Guardians. Through 2014, I could barely keep up on all the papers and news reports dealing with this utterly new and (to many) disturbing conservation strategy. Using "Google Alerts" to ongoingly learn of new publications has been a great help in recent years for keeping this page up to date, while preserving its complex history.
        As of July 2016 the debate and the publications arising from it have tapered off enormously. "Assisted migration" (by whatever term used) is now a standard entry in revisions to management plans for continuing to conserve lands, waters, and biodiversity in this century of rapid climate change. Assisting native species in moving upslope, poleward, and toward climate refugia is now just one more acceptable tool for moving ahead with "climate adaptation." By far, public and private forestry professionals have moved the fastest and farthest in forecasting when and where native tree species should be given a boost, and implementation is well underway in the forests of Alaska and western Canada (hardest hit by climate change in North America.) Hence, the above linked table of contents singles out assisted migration as it pertains to forestry.
        Henceforth (from 2016 onward) the occasional highly substantive article will be added within the above list of topics (that blend together all past years). But there will now be an additional category to draw attention to the truly significant papers, analyses, or reports, filed year by year:

  • 2016
  • 2017
  • 2018
  • 2019
  • 2020
  • 2021
  • 2022
  • 2023
  • 2024
  • As of 2017, a crucial shift has occurred in the FORESTRY perspective on "assisted migration": A multi-author Journal of Forestry paper makes clear that prior terminology and discussion re "assisted migration," "facilitated migration," and the like is no longer relevant — primarily because it is no longer a debatable issue in the abstract. Rather, "introducing future-adapted tree species" is now an accepted management tool for forest managers aiming to "adapt" forests to ongoing climate change via any and all of the three major categories of approaches (from weakest to strongest): resistance, resilience, and transition. Henceforth, what used to be singled out as novel and controversial — "assisted migration" of species poleward or upslope — will be regarded as species-specific forms of "transition." Access the full text of the paper in pdf:

    "Adaptive Silviculture for Climate Change: A National Experiment in Manager-Scientist Partnerships to Apply an Adaptation Framework", by Linda M. Nagel et al., Journal of Forestry, May 2017, 17 pp. See also a user-friendly version of the paper's major points at Climate Change Response Framework website.
    As of 2018, a 22-page REVIEW PAPER, with 42 co-authors, was published that offers the most up-to-date and practically oriented single publication for CONSERVATION BIOLOGISTS to absorb. The link below advances to an extensive collection of excerpts from this paper, which in full exists behind a paywall.
  • REVIEW PAPER: Managing consequences of climate-driven species redistribution requires integration of ecology, conservation and social science - by Timothy C. Bonebrake et al. (42 coauthors; 22 pages), 2018, Biological Reviews
  • Then 2019 rolls in with the Sierra Club fashioning the Jan-Feb issue of its national magazine to the theme of climate change adaptation. "Can We Help Our Forests Prepare for Climate Change?", by Madeline Ostrander. Reporting on assisted migration experimentation and intense deliberation at Maine's Acadia National Park, Ostrander shows that, once journalists turn their attention away from the tree-name-brand parks (Joshua Tree and Sequoia & Kings Canyon, which of course resist the idea of helping their namesakes move poleward), even the stewards of our most pristine and celebrated landscapes are willing to trade the 1491 static standard for the pragmatic necessity of 21st century climate preparedness and triage.

    In 2020, massive forest fires in Australia and the western United States have made climate adaptation in the forestry profession a necessity, with news articles informing the public. For biodiversity conservation, a review paper published in Conservation Biology is titled, "Importance of species translocations under rapid climate change."

    In 2021 the October UN "Convention on Biological Diversity" in China is the stimulus for an April Policy Forum (advocacy) piece published in Science journal by an international group of 7 authors, "Global policy for assisted colonization of species."

    In 2022, Greg Breining wrote an extensive article for the Minnesota Conservation Volunteers magazine that can serve as a primer for popular audiences to learn about the three forms of climate adaptation that foresters have begun using, "Resistance, Resilience, and Assisted Migration". Examples of all three that are underway in the state of Minnesota are surveyed, with tree species (both "climate winners" and "climate losers") specified and with memorable quotations from those doing the research and those putting the research in practice. The article: "New Forest for a New Climate".

    IPCC Climate Change Report 2014

    "Impacts, Adaptation, and Vulnerability"

       In the 44-page "SUMMARY FOR POLICYMAKERS" of this multi-volume report, Figure SPM.5, along with its caption and a summary paragraph, refer not only to the possible need for "assisted species migration", which ongoing climate change could necessitate to avert extinction and ecological disruptions, but also points to trees as being the most vulnerable of all life forms — and thus the most in need of human assistance to keep pace with climate zone changes. Trees are represented in the left-most vertical bar in image left, "Maximum speed at which species can move (km per decade)".

    (p. 15) "Many species will be unable to track suitable climates under mid- and high-range rates of climate change during the 21st century (medium confidence). Lower rates of change will pose fewer problems. Some species will adapt to new climates. Those that cannot adapt sufficiently fast will decrease in abundance or go extinct in part or all of their ranges. Management actions, such as maintenance of genetic diversity, assisted species migration and dispersal, manipulation of disturbance regimes (e.g., fires, floods), and reduction of other stressors, can reduce, but not eliminate, risks of impacts to terrestrial and freshwater ecosystems due to climate change, as well as increase the inherent capacity of ecosystems and their species to adapt to a changing climate (high confidence)."

    Editor's Note: The diagram above is generic; specific examples will vary, eg., this troubling report published in a top science journal in July 2015: "Climate change impacts on bumblebees converge across continents", by Jeremy Kerr et al., Science 20 July 2015. DESCRIPTION: "Responses to climate change have been observed across many species. There is a general trend for species to shift their ranges poleward or up in elevation. Not all species, however, can make such shifts, and these species might experience more rapid declines. Kerr et al. looked at data on bumblebees across North America and Europe over the past 110 years. Bumblebees have not shifted northward and are experiencing shrinking distributions in the southern ends of their range. Such failures to shift may be because of their origins in a cooler climate, and suggest an elevated susceptibility to rapid climate change." EXCERPT: "Bumblebee species' range losses from their historical southern limits have been pronounced in both Europe and North America, with losses growing to 300 km in southern areas on both continents. Mean elevations of observations for southern species have risen 300 m since 1974." IMPLICATIONS FOR ASSISTED MIGRATION are included as author quotes in a Christian Science Monitor summary article:

    "An advantage of assisted migration is that maybe we can give them a hand to catch up with climate change," Kerr says. "They're just not doing it by themselves. And bumblebee species, in a practical sense, are not really a group you want to try to do without."
         But assisted migration is a controversial measure, especially when it means introducing foreign species to new ecosystems. But in Kerr's view, these ethical questions are small when compared to the ethical and practical implications of extinction. "Is it ethically correct of us to introduce species to places they were never historically present in? In a sense, it's kind of like creating an invasive species," Kerr says. "But these are areas that are adjacent to the places where these species are found normally. So you're extending their range. It's not like we're taking species from Europe and introducing them to Hawaii, which would be crazy."

    The "IUCN Guidelines for Reintroductions and Other Conservation Translocations" 2012 update makes a distinction between two forms of "translocations" that would characterize conservation actions responsive to the ecological upsets of climate change (see also 2013 final):

  • ASSISTED COLONIZATION is the intentional movement and release of an organism outside its indigenous range to avoid extinction of populations of the focal species.

  • ECOLOGICAL REPLACEMENT is the intentional movement and release of an organism outside its indigenous range to perform a specific ecological function.

    See the 3-fold chart immediately below for distinctions between three forms of climate-responsive assisted colonization, as set forth by foresters.

  •     "Assisted Migration: What It Means to Nursery Managers and Tree Planters" (2014), intended for federal, state, and provincial forest managers, urges that planting for climate change become integral to the profession. Three types of climate assistance are:

    (1) Assisted population migration
    (2) Assisted range expansion
    (3) Assisted species migration (species rescue)

    Note: Species examples for each: Western Larch, Ponderosa Pine, Florida Torreya

        Considerations for restoring temperate forests of tomorrow: forest restoration, assisted migration, and bioengineering.

    This 2015 paper by Dumroese et al. sorts through the plethora of terms in conservation biology, forestry, and restoration ecology that refer to new management tools for climate adaptation.

    Notice that the 3 columns of bright green at the bottom of the chart offer nuances for the 3-category scheme depicted in the image directly above.

    This chart provides the key definitions for one of the three management tools specified in the title: assisted migration. This paper also deals with ecological restoration and bioengineering (genetic manipulation).

  • Editor's note:
    The historical sequence of the controversy over terminology can be accessed here: "Assisted Migration or Assisted Colonization: What's in a Name?"

  • EARLIEST PAPERS (1985, 2004, 2006, 2007)

  • "The Greenhouse Effect and Nature Reserves", by Robert L. Peters and Joan D.S. Darling, 1985, Bioscience

    Although the modern debate about assisted migration began around 2007, prominent conservation biologists recognized decades earlier that, should global warming continue, humans would indeed need to play a role in assisting species to migrate to cooler realms.

    Below is the first widely-cited CONSERVATION BIOLOGY paper, 1985, to recognize that GLOBAL WARMING would make HUMAN ASSISTANCE IN MIGRATION necessary. Published in the journal Bioscience, this paper by Robert L. Peters and Joan D.S. Darling is also highly recommended for its thorough and well-written overview of the basic concepts in conservation biology.  EXCERPTS: "... If estimates of a several-hundred-kilometer poleward shift in temperate biotic belts during the next [21st] century are correct, then a localized population now living where temperatures are near its maximum thermal tolerance would have to shift northward at a rate of several kilometers per year to avoid being left behind in areas too warm for survival...."

       "... Although some species, such as plants propagated by spores or dust seeds, may be able to match these rates, many species could not disperse fast enough to compensate for the expected climatic change without human assistance." (p. 711)
         "... If such measures are unsuccessful, and old reserves do not retain necessary thermal or moisture characteristics, individuals of disappearing species may have to be transferred to new reserves.... "It makes sense to locate reserves as near the northern limit of a species' range as possible, rather than farther south, where conditions are likely to become unsuitable." (p. 715)

    • 2002/2004 - "Assisted migration" (Brian Keel, attributed p. 31 of Oxford Dictionary of Ecology). Later (March 2011), Brian G. Keel et al. published in the journal Castanea, "Seed Germination of Habenaria repens (Orchidaceae) in situ Beyond its Range, and its Potential for Assisted Migration Imposed by Climate Change".

    • Winter 2004/2005 - "Assisted Migration of an Endangered Tree", Forum section of Wild Earth entailing two papers: "Bring Torreya taxifolia North — Now" (by Connie Barlow and Paul S. Martin), and "Conservationists Should Not Move Torreya taxifolia" (by Mark Schwartz). The term "assisted migration" appears 7X in the Barlow and Martin paper and 13X in the paper by Schwartz. Definitions derived from context:

    BARLOW & MARTIN: "Many botanists and climate specialists agree that at some point in the future, human-induced global warming will push many plants to the edge of viability; at that time, 'assisted migration' (a term coined by Brian Keel, 2004) may be the only stay against extinction.... Let us undertake assisted migration for Torreya taxifolia today, in part, as a trial run for the decades to come. With Florida torreya we can explore the ecological and social dimensions of what seems likely to be a radically new era for plant conservation."

    SCHWARTZ: "Thus, the reasoning goes, if we assist migration northward, the species is likely to thrive, thereby assuring the persistence of one of this continent's most distinctive conifers. Based on my reading, research, and personal experience, I find some merit in this argument; Torreya taxifolia is a glacial relict, quite likely on the edge of its climatic tolerance, and might do well in a cooler climate.... Nevertheless, assisted migration sets a risky precedent. Will control assurances and monitoring of problems be followed for future species that are deemed to be in need of assisted migration? I fear not. Thus, it is critical that we take a hard look at what criteria are to be used to justify assisted migration and develop guidelines for appropriate assisted migration in order to preserve biological diversity."

    • July 2006 - "Predicting Extinctions As a Result of Climate Change", Mark W. Schwartz, Louis R. Iverson, Anantha M. Prasad, Stephen N. Matthews, and Raymond J. O'Connor, Ecology.
    Conservation management has already shifted its emphasis away from narrowly endemic small populations (Schwartz 1999) based, in part, on ecological theory suggesting that these species may be unsustainable. If one asserts that narrowly endemic species are doomed to extinction by climate change, then logic dictates that we either begin programs of assisted migration or divert conservation resources away from these 'doomed' species. Divesting of in situ conservation efforts on behalf of narrow endemics as a consequence of warming must be regarded as premature without specific evidence of climatic sensitivity.

  • "Assisted Migration" chapter of 2007 PhD thesis by the scientist who coined the term: Brian Keel.
    The full title of Keel's thesis is "Assisted Migration as a Conservation Strategy for Rapid Climate Change: Investigating Extended Photoperiod and Mycobiont Distributions for Habenaria repens Nuttall (Orchidaceae) as a Case Study". The link above connects to a PDF of his chapter 3. Note: His PhD thesis abstract is available online and in book format: Assisted Migration as a Conservation Strategy for Rapid Climate Change: Investigating Extended Photoperiod and Mycobiont Distributions of Habenaria Repens Nuttall (Orchidaceae) as a Case Study. Keel is also coauthor of a chapter on Managed Relocation in a 2012 edited volume, Plant Reintroduction in a Changing Climate: Promises and Perils.

  • "When Worlds Collide" by Douglas Fox, Conservation Magazine, Jan-March 2007 (cover story).
    Subtitle: "Climate change will shuffle the deck of plants, animals, and ecosystems in ways we've only begun to imagine."
    Content: Surveys beginnings of debate about whether to actively assist species in shifting their geographic ranges. The work of Torreya Guardians is mentioned.

  • "A Radical Step to Preserve Species: Assisted Migration" by Carl Zimmer, New York Times (Science Times), 23 January 2007 (lead story).
    Zimmer's next NYT story is 18 Sept 2014: "For Trees Under Threat, Flight May Be Best Response". EXCERPT: "Traditionally, conservation biologists have sought to protect endangered plants and animals where they live, creating refuges where species can be shielded from threats like hunting and pollution. But a refuge won't help the whitebark pine, and so now scientists are pondering a simple but radical new idea: moving the trees to where they will be more comfortable in the future. It's called assisted migration, and the debate over its feasibility comes as biologists everywhere begin to reassess their tactics and the impact of climate change on endangered species."

  • "A Framework for Debate of Assisted Migration in an Era of Climate Change" by Jason S. McLachlan, Jessica J. Hellman, and Mark W. Schwartz, Conservation Biology, April 2007, Vol 21: 297-302.
    Editor's note 2021: Because this paper has become a much-cited classic, the entire short CONCLUSION is printed here. Because this annotated links webpage is on the Torreya Guardians website, the first two paragraphs of the INTRODUCTION (which uses Florida Torreya as the example) will follow the conclusion.

    CONCLUSION: Regardless of forthcoming scientific progress, the magnitude of impending climate-driven extinctions requires immediate action. Delays in policy formulation and implementation will make the situation even more urgent. We advocate developing management strategies with the flexibility to respond to emerging insights from basic and applied research, but we cannot wait for better data. To an uncomfortable extent this war will have to be fought with "the army we have, not the army we want."
         The current literature shows that data collected for other purposes often provide useful guidance for thinking about assisted migration. Nevertheless, research specifically focused on assisted migration will be needed before science can answer questions fundamental to informed policies of assisted migration: Is there a demographic threshold that should trigger the implementation of assisted migration? What suite of species should be prioritized as candidates for translocation? How should populations be introduced to minimize adverse ecological effects?
         Questions such as these should be formulated and addressed by a broad group of scientists, managers, and policy makers. A consensus that identifies the risks and opportunities of alternative approaches to assisted migration and suggests ecologically sound best-management strategies would be a significant step toward developing a coherent policy on this issue. The alternative strategy of waiting to see what happens is an abdication of our values and responsibilities.

    INTRODUCTION: The Torreya Guardians are trying to save the Florida torreya (Torreya taxifolia Arn.) from extinction (Barlow & Martin 2004). Fewer than 1000 individuals of this coniferous tree remain within its native distribution, a 35-km stretch of the Apalachicola River, and these trees are not reproducing (Schwartz et al. 2000). Even if the Florida torreya was not declining toward extinction, the species would be at risk from climate change. Warming is projected to either significantly reduce or eliminate suitable habitat for most narrowly endemic taxa (Thomas et al. 2004; Hannah et al. 2005; Peterson et al. 2006), forcing species to colonize new terrain to survive.
         The focus of Torreya Guardians is an "assisted migration" program that would introduce seedlings to forests across the Southern Appalachians and Cumberland Plateau ( Their intent is to avert extinction by deliberately expanding the range of this endangered plant over 500 km northward. Because planting endangered plants in new environments is relatively simple as long as seeds are legally acquired and planted with landowner permission, the Torreya Guardians believe their efforts are justified. Introducing this species to regions where it has not existed for 65 million years is "[e]asy, legal, and cheap" (Barlow & Martin 2004).

    FINAL PARA OF THE INTRODUCTION: Assisted migration is a contentious issue that places different conservation objectives at odds with one another. This element of debate, together with the growing risk of biodiversity loss under climate change, means that now is the time for the conservation community to consider assisted migration. Our intent here is to highlight the problem caused by a lack of a scientifically based policy on assisted migration, suggest a spectrum of policy options, and outline a framework for moving toward a consensus on this emerging conservation dilemma.

  • "Climate Change and Moving Species: Furthering the Debate on Assisted Colonization" by Malcolm L. Hunter, 2007, Conservation Biology Vol 21: 1356-58.
    EXCERPTS: With global climate change looming large in the public psyche, the recent paper by McLachlan et al. (2007) and its popular accompaniment (Fox 2007) are timely indeed. Of course some conservation biologists will not wish to think about the prospect of actively moving species that are threatened with extinction by climate change. For them this would be almost analogous to handing out placebos in the midst of an epidemic and worse yet, these placebos may have serious unintended consequences if translocated species become invasive.
         McLachlan et al. propose framing the debate around two considerations — perception of risk and confidence in ecological understanding — that can be construed to generate an axis or continuum from scientists who would strongly support assisted colonization to those who would oppose it. I think it is useful to advance this exercise by considering three issues that can also be construed as continua: species that are more or less acceptable to translocate, sites that are more or less acceptable for receiving translocations, and projects that are more or less acceptable because of their socioeconomic ramifications and feasibility. I have used the term assisted colonization in contrast to assisted migration used by McLachlan et al. because many animal ecologists reserve the word migration for the seasonal, round-trip movements of animals (Wilcove 2007) and because the real goal of translocation goes beyond assisting dispersal to assuring successful colonization, a step that will often require extended husbandry.
         Candidate species for assisted colonization can be characterized by three features: their probability of extinction due to climate change, their vagility, and their ecological roles.... Evaluating sites that might receive translocated species brings four more issues to light.... Evaluating species and sites is clearly within the purview of biologists, but there is a third set of issues — cost, technology, and humaneness — that will require attention from both biologists and social scientists.
         The cost of translocations will vary enormously depending on the biology of the target species. Perhaps as important is the issue of who should bear these costs. Having a species-focused group such as the Torreya Guardians ( dedicate their money and time to a translocation may be more acceptable to the conservation community than if a government agency or broad-based environmental group, such as The Nature Conservancy, does so. In the latter case many will argue that efforts would be better allocated to conserving whole ecosystems and their connectivity. On the other hand, organizations with a broader mandate might evaluate assisted colonization in a more balanced and accountable way.
         . .. McLachlan et al. provide a thoughtful overview of the biological research questions raised by the prospect of assisted colonization, but they do not explicitly address social science research. For example, will people living in or near the current range of a local endemic oppose having individuals removed from the local population, and, conversely, will people living near the translocation site resist the introduction of an "exotic" species even if it is a "climatic refugee"....


  • "Coming to Terms with the Concept of Moving Species Threatened by Climate Change — A Systematic Review of the Terminology and Definitions" - by Maria H. Hallfors et al., 2014, PLOS ONE.
    EDITOR'S NOTE in 2020: This widely cited paper demonstrates that the term "assisted migration" (favored on this website by Torreya Guardians, and whose early usage is reported here by Barlow: "Assisted Migration or Assisted Colonization: What's In a Name?") had become the lead term as of 2014. Abundant usage of "assisted migration" in forestry journals began in 2011, swamping the reluctant engagement with the topic in conservation biology. By 2018, however, practicing foresters had perhaps wisely chosen to use more moderate terms for the same concept, hence: "adaptive management" and revised standards for "seed selection" and "species selection", drawing upon seeds and tree types from more southerly realms. In distinguishing forestry applications from those of conservation biology, the authors of this 2014 paper wrote,
    ... We noticed a discrepancy in the definition of the measure between the fields of conservation and forestry. Most of the forestry-related definitions emphasised a silvicultural viewpoint, which is not included in the original idea of assisted migration, which has to do with safeguarding biodiversity. Pedlar et al. [65] place forestry in the assisted migration debate by introducing the concepts forestry assisted migration and species rescue assisted migration. This is a movement in the right direction, since it distinguishes these two concepts, which are fundamentally different in their goal. Nevertheless, to avoid confusion, we suggest that other terms should be used for strategies seemingly similar to assisted migration but applied for purposes other than safeguarding biodiversity. Choosing suitable provenances in the context of agri-, silvi- or horticulture in relation to anticipated changes in climate could be called, e.g., predictive provenancing [80] to avoid confusion with assisted migration.
       ABSTRACT: Intentional moving of species threatened by climate change is actively being discussed as a conservation approach. The debate, empirical studies, and policy development, however, are impeded by an inconsistent articulation of the idea. The discrepancy is demonstrated by the varying use of terms, such as assisted migration, assisted colonisation, or managed relocation, and their multiple definitions. Since this conservation approach is novel, and may for instance lead to legislative changes, it is important to aim for terminological consistency. The objective of this study is to analyse the suitability of terms and definitions used when discussing the moving of organisms as a response to climate change. An extensive literature search and review of the material (868 scientific publications) was conducted for finding hitherto used terms (N=40) and definitions (N=75), and these were analysed for their suitability.

    Based on the findings, it is argued that an appropriate term for a conservation approach relating to aiding the movement of organisms harmed by climate change is assisted migration defined as follows: Assisted migration means safeguarding biological diversity through the translocation of representatives of a species or population harmed by climate change to an area outside the indigenous range of that unit where it would be predicted to move as climate changes, were it not for anthropogenic dispersal barriers or lack of time.

    The differences between assisted migration and other conservation translocations are also discussed. A wide adoption of the clear and distinctive term and definition provided would allow more focused research on the topic and enable consistent implementation as practitioners could have the same understanding of the concept.

    INTRODUCTION: As the effect of climate change on biodiversity is becoming more evident through, e.g., spatial changes in species' suitable areas (e.g., [1]�[4]), translocation of organisms has been proposed to avoid the loss of biodiversity and to complement current conservation strategies. The idea was, to our knowledge, first proposed by Peters and Darling in 1985 [5], and nine years later termed human-assisted dispersal [6]. Since then, numerous other terms have been applied, including assisted migration, first used by Whitlock and Milspaugh in 2001 [7], assisted colonisation first used in 2007 [8], and managed relocation in 2009 [9]. In addition, the initial proposal [5] has also been articulated in various ways. Different terms have been used to refer to similar ideas, while one term may be used to denote different ideas.... Terminological confusion may lead to poor comparison of one study with another and can seriously hamper scientific development. This, in turn, perturbs public discussion and decision-making and, thus, harms efficient application

    MATERIALS and METHODS: To quantify the discussion on the proposed conservation approach and to generate data to analyse the prevailing terminology and definitions, we conducted a literature search. We used the search query ("assisted migration" OR "assisted coloni*ation" OR "managed relocation" OR "human-aided translocation" OR "assisted translocation" AND "climate change") to search for literature published in English up until the end of 2012. These terms represented our initial understanding on which might be the most commonly used terms for the idea. We included "AND climate change" since an omission of it resulted in a large number of hits that were irrelevant to this study.... In the analysis of definitions of the measure we included only peer-reviewed articles that in their title, abstract, or keywords mention a relevant term for the general measure....


  • "Reconstructing a Deconstructed Concept: Policy Tools for Implementing Assisted Migration for Species and Ecosystem Management" - by Roxane Sansilvestre et al., 2015, Environmental Science and Policy. EDITOR'S NOTE: This important paper distinguishes the Precautionary Principle, which restrains assisted migration actions (owing to hypothetical risks of invasiveness), from the Prevention Principle, which in this case means prevention of extinction or prevention of loss of ecosystem services.

    EXCERPTS: "Despite the fierce debate that AM [assisted migration] has recently produced between opposing actors who see more risks than benefits in AM initiatives and those seeking to act in the face of climate change threats, AM could be nevertheless seen simply as an extension of the practices of translocation and reintroduction of endangered species. In fact, the distinction between translocations and AM is becoming increasingly artificial because climate change makes parts of the historic ranges of many species unsuitable as reintroduction recipient sites.

  • "The inclusion of AM as an explicit climate adaptation option in environmental policies will involve integrating clearly climate change constraints in regulations and by consequence allowing for increased flexibility, while improving at the same time the management of associated risks. This means that the risks of invasiveness, for example, would be considered not more important than the risks of extinction, so regulations could open windows to experimental translocations under controlled semi-natural environments. Here, the complexity is that policy-makers should implement regulations for two-fold precautionary actions, for extinction risks and AM risks. Probable extinctions could be avoided by facilitating appropriate management actions even if risky, and management risks should be decreased by a responsible, reactive and reasonable biodiversity management.
        "Thus, experimentation must remain a first essential step to be able to measure the real extent of the risks involved. Concerning the risk of genetic pollution, management guidelines must consider integrating new ecological and genetic interactions because of the translocations. Even if genetic pollution could damage ecosystems it could also represent an opportunity for adaptation. Policy-makers and managers must accept that some degree of maladaptation could be the first step before natural selection adjusts populations to the new environmental conditions
        "Degraded forests could be used as an experimental opportunity for AM by bringing new genetic material from lower latitudes and/or altitudes to reinforce local populations. This type of forest restored through AM would be managed for optimality in biomass production or carbon sequestration while other better conserved areas would be managed for biodiversity conservation. In turn, people using plants for restoring different habitats can follow the experimental approach example from the forestry community and set up seed certification schemes based on networks of reciprocal transplant tests to understand the functional limits of common species used in restoration."

  • Why we disagree about assisted migration: Ethical implications of a key debate regarding the future of Canada's forests, by I. Aubin, C.M. Garbe, S. Colombo, C.R. Drever, D.W. McKenney, C. Messier, J. Pedlar, M.A. Saner, L. Venier, A.M. Wellstead, R. Winder, E. Witten and C. Ste-Marie, in The Forestry Chronicle, Nov/Dec 2011.
    EXCERPTS: ... Numerous timber species native to Canada have been planted in Europe, including Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), Sitka spruce (Picea sitchensis [Bong.] Car- ri�re) and Lodgepole pine (Pinus contorta Dougl. ex Loud.). In comparison, planting of exotic tree species for industrial forestry purposes in Canada has not extended much beyond limited plantings of Norway spruce (Picea abies [L.] Karst.), Siberian larch (Larix sibirica Ledeb.) and Scots pine (Pinus sylvestris L.). So how does assisted migration differ from historic human-mediated species introductions? At least two important distinctions can be made. First, modern-day species movements are carried out under increased scrutiny and regulation; interested parties are often highly attuned to the potentially devastating impacts of introduced invasive species on natural ecosystems. Second, assisted migration is being proposed to reduce the impacts of human-induced climate change, an unprecedented situation in human history that brings with it entirely new environmental, societal and ethical challenges.
         .... As with many issues surrounding climate change, assisted migration is a complex topic that encompasses scientific, social, policy and economic viewpoints, for which different stakeholders have their own complex and multi-dimensional objectives, metrics and definitions.... The current scientific debate on assisted migration appears stalled between proponents who feel compelled to override natural processes and help nature adapt to human-induced change, and detractors who feel that nature should be left alone and all efforts directed towards reducing human impacts. Therefore, the debate has moved beyond a strict scientific discussion into the arena of beliefs, values, visions of the future, and subjective perceptions of risk and desirable outcomes. These elements underpin our individual moral judgments about what nature is and where we fit within it and thus are a critical dimension in any position regarding assisted migration.
         ... We list the three main objectives of assisted migration as found in the literature and discuss the different types of movements associated with each: (1) Preventing the extinction of species, (2) Enabling or conserving market-based goods (e.g., timber), (3) Enabling or conserving ecosystem processes and services.
         Preventing the extinction of species ... is the prevailing objective found in the literature, whereby species of conservation concern are moved to locations expected to be climatically suitable based on projections of future climate (e.g., Carroll et al. 2009, McLane and Aitken 2011). In most cases, this involves moving individuals of a given species beyond its historical range limits (i.e., assisted long-distance migration; Ste-Marie et al. 2011). If, however, the motivation is to conserve a target species by maintaining or improving its genetic diversity, a selected population may be moved inside the species' range (i.e., assisted population migration; Ste-Marie et al. 2011).

    Potential Consequences - The Ecology of Action vs. Non-Action. Many similarities are shared between the potential ecological consequences of climate change and those of assisted migration (Table 1). These similarities illustrate the contradictory outcomes that assisted migration introduces into the decision-making process. As assisted migration is primarily intended to emulate or accelerate the process of species migration, one of the main ecological consequences of climate change, assisted migration also has the potential to create negative consequences similar to those of climate change. For instance, a prevailing objective of assisted migration is to prevent species extinction via the translocation of a selected species into a new environment. However, if a translocated species flourishes in its new environment, it could induce unintended additional stress to the local community, causing reduced abundance or even extirpation of some native species at the recipient location (see Box 1 for a more detailed example). In this section, we discuss the primary potential ecological consequences of climate change, which can also be considered reasons for assisted migration. We follow this by presenting the potential negative consequences of assisted migration as identified by opponents. We finally highlight uncertainties that limit our capacity to adequately assess the potential risks and benefits of assisted migration.... One's view of the relationship between humans and the natural world, the sense of duty to intervene, and beliefs about nature's sensitivity to anthropogenic change are all determining factors that influence perceptions of assisted migration and one's willingness to act on it.

    The Ethics of the Problem. ... Ecocentrists are likely to consider assisted migration as a diverted effort; "...a techno-fix restricted to treating the symptom of biodiversity loss, implying that no fundamental change in human activities is required..." (Fazey and Fischer 2009). From an ecocentric perspective, climate change interventions should be restricted to a strong reduction of human impact on nature (i.e., reduction of greenhouse gas emissions and other anthropogenic stressors). This position focus on climate change mitigation and view adaptation initiatives, such as assisted migration, as "giving up" on the problem. However, in some cases, ecocentrists might consider assisted migration for the intrinsic value of a species (e.g., the Torreya Guardians) or consider assisted migration with the aim of preserving key ecosystem processes such as carbon sequestration. Nevertheless, they are likely to be sceptical about the capacity of assisted migration to reach this goal, the objectives of preserving ecosystem processes by assisted migration being far from well-understood or studied.

    Exploration of Two Perspectives on Assisted Migration. Currently in Canada, two disciplines are directly involved in assisted migration issues — conservation and forestry. While we found a large amount of published material on this topic in the conservation literature, very little was found outlining the forestry perspective. However, it is the forestry sector that is currently initiating assisted migration in Canada, with a few provinces modifying seed transfer rules to allow large-scale assisted migration to proceed (Pedlar et al. 2011). We are currently aware of only one assisted migration initiative in Canada that is aimed at species of conservation concern; a research trial testing the establishment of the Whitebark pine (Pinus albicaulis Engelm.) north of the species' range (McLane and Aitken 2011).

    Concluding Remarks: Societal Responses or How to Agree on Assisted Migration. To facilitate discussion, a clear definition of the objectives and metrics of a proposed assisted migration initiative is needed. To date, the conservation community has focused on assisted migration as a means to mitigate species extinction, while the forestry community has focused on maintaining or increasing tree productivity. These two goals involve different types of movements, each with unique risks and benefits. Maintaining a distinction between these different types of assisted migration (and attendant risks and benefits) may help clarify opinions on the topic. However, risk assessment is unlikely to produce a consensus on assisted migration considering the uncertainties remaining around this complex issue. Also, it is important to outline that even an apparent absence of risk would not be sufficient to justify an action; underlying values, motives, principles and goals matter in decision-making (Sandler 2009). In other words, many important questions related to assisted migration cannot be answered by simple risk assessments.... We need a discussion of what the subject of the assessment of risk should be; we also have to discuss the ethical guideposts we use when we have to cope with significant uncertainties: the anthropocentric and ecocentric positions or the attitudes towards intervention and technology. But maybe more importantly we should simply start the discussion by clearly identifying the goals and underlying values for different assisted migration actions and then search for common ground.

  • Scientists, Managers, and Assisted Colonization: Four contrasting perspectives entangle science and policy, by Mark W. Neff and Brendon M. H. Larson, 2014, Biological Conservation
    "Here, we treat scientific opinion of this conservation controversy as a subject of empirical social research in order to provide a richer understanding of the terms of the debate. . . The debate over assisted colonization has largely been framed by academic conservation scientists, so the views of other stakeholders remain underrepresented. To begin to redress this lacuna, we examine the views of the managers who would enact assisted colonization and evaluate its consequences on the ground. There is reason to suspect that managers' views will differ from those of scientists because their direct engagement with conservation practice makes them more intimately familiar with constraints to the application of ecological theory in conservation decision-making."

    HIGHLIGHTS (posted by authors): (1) We use Q method [blend of quantitative and qualitative] to identify axes of dissent regarding assisted colonization amongst scientists and managers; (2) Four groups emerged with distinct ideas about assisted colonization; (3) Disagreements centered on non-technical aspects of the problem; (4) Assisted colonization is a trans-scientific and wicked problem; (5) Lack of shared values may preclude successful implementation of assisted colonization.

    POPULAR SUMMARY BY NEFF: "Using Q method, a technique that blends aspects of quantitative and qualitative social science research, Brendon Larson and I examined the scientific controversy surrounding proposals to move species to new areas as a climate change adaptation strategy. Some conservation biologists see assisted colonization, as the proposal is called, as a necessary evil; to others it is akin to apostasy. Our research systematically evaluates the scientific, policy strategic, and value-based considerations that underlie ongoing disputes that have filled the pages of recent issues of conservation biology and forestry journals. Research such as this exposes where the protagonists in current debates are talking past one another based on different technical understandings, as well as elements of the dispute that are fundamentally about differing values. This is a first step to facilitating nuanced discussion of the value disputes, a pre-requisite for progress toward a resolution."

    Editor's note: What follows are extracts from the narrative descriptions of the FOUR DISTINCT PERSPECTIVES that emerged from the survey:

    ECOLOGICAL INTERVENTIONIST: The Ecological Interventionists accepted significant human management of 'nature,' believing conventional conservation strategies to be necessary for the conservation of biodiversity, but not sufficient in an era of climate change, thus necessitating options such as assisted colonization. These respondents did not perceive assisted colonization to be a radical transformation of natural ecosystems, but rather a necessary response to anthropogenic climate change and an extension of natural processes: "Species have been moving around throughout geological time, mostly under the influence of climate change. It is a very anthropocentric and short-term view to believe that all species should remain exactly where they were perceived to be over the past few hundred years." We do not, according to this logic, have the luxury of conducting "a vast research program before assisted colonization can begin." "There is no time!'" one participant responded. Others emphasized that assisted colonization is already occurring. Another suggested that while "more research is always needed, [awaiting a vast research program] creates a situation where we do nothing but throw a bit of money towards monitoring as species and communities slide into functional extinction."
         The Ecological Interventionists were less concerned than their peers by the idea that citizen groups with appropriate expertise might participate in assisted colonization, but still believed in the importance of following approved and reviewed plans. One participant reported, "I view humans as part of nature, and therefore human interests as part and parcel of our interests in sustaining ecosystem productivity and stability." Further indicating some tension about the role of science in assisted colonization decision-making, a manager wrote that we need structured decision-making methods because scientists tend to resort to a biased "natural is best" ideology.

    NATIVIST TECHNOCRATS: The Nativist Technocrats are committed to saving species from potential extinction, but prefer to do so by minimizing human influence on nature rather than by intervening in ecosystems. The 'Technocrat� portion of the title for this group reflects their strong rejection of movement of species by expert citizens; they believe that scientists should retain decision-making authority and professionals should conduct conservation work. Whereas the other groups felt that assisted colonization had a role to play, the Nativist Technocrats rejected it, not least because of concerns about introducing diseases or invasive species. One scientist asked, "Do we keep moving species further and further poleward or uphill as the climate warms? Until we run out of hill or latitude? If global warming is not mitigated it will be catastrophic for ecosystems and humanity. Assisted colonization is a hopeless strategy for dealing with climate change and may provide the illusion that mitigation is not necessary."

    INTERVENTIONIST TECHNOCRATS: In contrast to the Nativist Technocrats, the Interventionist Technocrats were amenable to assisted colonization as an important and necessary conservation tool. They were technocratic insofar as they strongly disagreed with basing ecological practice on people's preferences. One clarified that these decisions "should be based on science" and another that "bias play[s] too important [a] part of human make up" to rely on people's preferences." They were the only group to disagree that we require "a framework for debates about subjective values surrounding species conservation" and strongly felt that citizen groups with appropriate expertise should not be allowed to move species. They also held the perspective, unique amongst the sampling pool, that endangered species laws are overly restrictive and thus need to be changed to successfully manage ecosystems in the face of climate change.

    RELUCTANT INTERVENTIONISTS: The Reluctant Interventionists were similar to the Ecological Interventionists, but we retained it as a distinct factor because of its unique perspectives on two issues. First, as the name indicates, the Reluctant Interventionists were far more cautious about implementing assisted colonization. Compared to Ecological Interventionists, they were more concerned about potential negative implications of introduced species and less pessimistic about the possibility of maintaining viable populations of native species under future climatic conditions. They did not easily embrace the idea of moving species, and none were optimistic that it will prove to be a panacea. Second, in contrast to the Ecological Interventionists who were neutral on the idea, this group emphatically rejected the statement that well-intentioned and informed citizen groups should be able to undertake assisted colonization activities without government approval and expressed comparative openness to ethical rejections of assisted colonization. In general, this group felt more strongly than the other groups that public values must be considered in assisted colonization decision-making.
         Of the four perspectives, the Reluctant Interventionists most strongly believed that ecosystems will change and species will go extinct regardless of whether we enact assisted colonization. They concluded that the risks of acting should be weighed against those of not acting, with one scientist elaborating that "I don't think there are perfect solutions nor perfect answers, so this approach [weighing risks] represents the best way forward." Despite the significant risks they identify, these respondents did not conclude that we need more research before utilizing assisted colonization, a sentiment shared with the Ecological Interventionists. They noted both that land managers are already doing things that could be considered assisted colonization and that waiting for definitive results would be detrimental.

  • A productive role for science in assisted colonization policy, by Mark W. Neff and Katherine Carroll, 2016, WIREs Climate Change. Advance, unedited pdf. Key section heads include: (1) Assisted Colonization is controversial because it forces uncomfortable questions; (2) More scientific humility may ensure the utilization of science; (3) The world is too diverse and complex to justify broad conclusions about the impacts of species movements; (4) Additional scientific knowledge does not dispel controversy based in value disagreement; (5) Potential paths forward.

  • Making the transition to the third era of natural resources management, by Nathan L. Stephenson, 2015, The George Wright Forum
    EDITOR'S NOTE: This is an ideal paper for probing the psychological anguish that accompanies the pragmatic shift in conservation paradigms forced by rapid climate change. The author has worked in Sequoia and Kings Canyon National Park for 35 years, and he wrote this essay as a contribution to the National Park Service Centennial in 2016.

    EXCERPTS: ... We are entering the third era of National Park Service (NPS) natural resources management — an era defined by rapid and unprecedented global changes. This third era promises to overturn not only some of our most fundamental assumptions about parks and protected areas, but also many of the ideals we currently hold dear. A common initial reaction to the diverse challenges of this transition is to feel overwhelmed and adrift; I have certainly had such feelings myself. But these feelings carry the risk of reducing our effectiveness as resource stewards right when we can least afford to be less effective: during a transition that is demanding us to be particularly clear-headed and far-seeing. Here I briefly examine some of the challenges of this new era, focusing on those that can most often elicit feelings of discouragement. When we examine the challenges individually, they begin to lose some of their ability to cast gloom — especially when we consider them in the light of lessons from an earlier fundamental transition in NPS natural resources management, beginning a half-century ago. [Here he is referring to the 1963 issuance of The Leopold Report; a section head is titled, "Letting Go of Leopold."] ... Recovery from this despair was gradual, with no flipping of light switches. Rather than abrupt epiphanies, I started to slowly piece together some possible new visions of the future of natural resources management in national parks. I eventually came to accept the loss of some of the ideals of the Leopold era, and began replacing them with new ideals that were better aligned to an era of rapid global changes.
         .. Based on my own experience and my reading of Revisiting Leopold I offer the following thoughts about what does and does not fall within a practical concept of ecological integrity. Ecological integrity does not demand that species be found in the same locations, or in the same abundances, as they were in the past. In the face of rapid global changes, species will move. Some will increase in abundance, and some will decline in abundance. Additionally, ecological integrity does not demand that "natural" communities (combinations of species) be maintained. One of the great lessons of ecology is that most species behave individualistically, responding to environmental changes by leaving some of their neighboring species behind and then reassembling in new combinations. But ecological integrity does include, to the extent possible, maintenance of regional native biodiversity. Even though native species may not occur at the same locations or in the same abundances as they did in the past, they are still present within the broader region. Some species may migrate northward out of a park and onto adjacent lands, while others migrate into the park from the south (perhaps even by assisted migration). The net result is that the broader region in which the park is embedded maintains most of its native biodiversity. As parts of broader landscapes, parks will continue to play a critical role in maintaining native biodiversity.
         ... Deciding to intervene. The Leopold era has been characterized by a tendency to rely, when possible, on natural processes to shape ecosystems. Accordingly, among NPS natural resource managers there is now often a strong, and appropriate, reluctance to intervene in ecosystems. But if, as suggested by Revisiting Leopold, ecological integrity is to become our new mooring in the era of rapid global changes, we can expect increasing impetus to intervene. The thought that human intervention in parks will only increase is quite discomfiting for many people. I usually hear three classes of argument against intervention: legal, ethical, and unintended consequences.
         ... To be clear, the very real risk of unintended consequences means that intervention should never be taken lightly. Additionally, as we enter the third era we are likely to consider unfamiliar forms of intervention — like assisted species migration — that could carry novel risks. Intervention remains a last resort that should be approached with great caution and forethought. But good reasons to intervene seem sure to increase in the current era of rapid and unprecedented global changes.
         ... Howard Shellhammer (one of the fire ecologists, then of San Jose State University) has told me of a particularly important ecological epiphany. When the researchers returned to the sites of the first experimental burns, they were greeted with carpets of giant sequoia seedlings — in an abundance they had never seen before, anywhere. The tight link between fire and profuse giant sequoia regeneration was made immediately clear. Small-scale experiments can make the abstract real, quickly propelling us to greater understanding. Just as small experiments helped usher in the Leopold era, they can help us make the transition to the post-Leopold era. For example, we could potentially learn much from small, carefully conceived assisted migration experiments. Assisted migration experiments could initially be limited to those that could easily be undone, such as with tree seedlings (if needed, the trees could be removed well before they reach reproductive age). Any assisted migration experiment would be at least as much a social science experiment as an ecological experiment. How do NPS employees react to such proposals at the park, regional, and national levels? Are there policy roadblocks? How do the press and public react? At worst, planning for such experiments would help make the abstract real, and thus could open critical discussions within and between NPS and the public. Even if the main lesson is that large parts of the public are not comfortable with assisted migrations in national parks, this is valuable information.
         ... To start answering our questions about the interplay of science and values, we will likely need to start small, and to get started sooner rather than later....
         Conclusion: It is normal to feel overwhelmed, at least initially, at the prospect of managing national parks and their natural resources in an era of rapid and unprecedented global changes. At a personal level, many of us need to grieve the passing of the Leopold era and the loss of some of its ideals, and then become secure in knowing that the broad outlines of a new vision are beginning to emerge. Indeed, each of us can contribute to the evolution of this new vision. We do not need to figure everything out at once; we can start with small experimental steps, learning as we go.

    See also a 2017 popular article on Stephenson's "existential" perspective on climate tragedy in the national park he works in here: "For the National Parks, a Reckoning", by Madeline Ostrander, Undark Magazine.

  • What risks matter? Public views about assisted migration and other climate-adaptive reforestation strategies, by Guillaume Peterson St-Laurent et al., Climatic Change, 5 November 2018.
    EDITOR'S NOTE: While this paper presents results of public values (via interviews) solely within British Columbia, the introduction and citations offer excellent background and key citations on the whole public values literature that has accumulated re the debate about "assisted migration", especially within the forestry context. Key image:

    EXCERPT: ... The observed differences in public views about the two AM strategies being considered by BC's government are notable. On the one hand, the high proportion of respondents who supported AM within natural range suggests that a large majority of BC's public is willing to see AM implemented in BC forests, as long as it abides by species' historical ranges. On the other hand, lower levels of support for AM outside of natural range indicate that the movement of species to other regions represents a contentious element that is, in the eyes of the public, somewhat comparable to the use of exotic species or GMOs. The relative lack of distinction between AM outside of natural range and long-range intercontinental species introductions observed here is consistent with previous research that identifies this issue as a barrier to public consensus in the assisted migration debate (Hewitt et al. 2011).
         In part, public perceptions of risk of AM outside of natural range are also consistent with expert assessments that similarly note increased ecological risks with spatial distance (Mueller and Hellmann 2008). Many of the risks associated with AM outside of natural range do not necessarily apply to AM within natural range (e.g., no chance of creating exotic invasive species; Hewitt et al. 2011). On the other hand, other experts argue that limiting AM to within range movements risks failing to adapt to expected future climates (Pedlar et al. 2012; Winder et al. 2011). Despite relatively low levels of support for AM outside of native range, this strategy was supported in principle by more than half of respondents. However, the majority (69%) believe that more research is needed before AM outside of natural range can be implemented (Fig. 3), thereby confirming the general sense that current uncertainties make its acceptance extremely challenging. The possibility that uncertainties can be reduced through further research (Aitken and Whitlock 2013; Vitt et al. 2010) opens the door to a conceivable decline in public opposition, if and when conclusions demonstrate that the benefits of AM outside of natural range outweigh the risks.

  • "Congruence between future distribution models and empirical data for an iconic species at Joshua Tree National Park" - by Lynn C. Sweet et al., June 2019, Ecosphere
    1 LONG PARA MENTIONS "ASSISTED MIGRATION": "Because assisted migration is a contentious issue, especially in a national park, our goal here was to inform management with the most robust available predictions, focusing on areas where the species occurs already. Given the known limitations of SDMs with regard to biotic interactions and other problems (Guisan and Thuiller 2005), validated in situ refugia provide a higher level of confidence regarding providing the essential resources for species and their commensal associates. Currently unoccupied, entirely new habitat cannot provide that same confidence. We assumed that the dispersal abilities of this species, small mammals being the likely dispersal vector (Vander Wall et al. 2006), are somewhat limited. That limited ability to track a rapidly changing climate, together with a long time to reproductive maturity and the timescale reflected in these end-of-century models, indicates threats to persistence of Joshua trees may worsen, unless the buffering abilities of climate refugia are sufficient to sustain populations. Therefore, we focused on areas of refugia for the species, occurring toward the leading edge of the current species' distribution within the park (relevant to in situ conservation efforts), rather than the entirety of future suitable habitat (areas relevant to assisted migration)...."
  • "Public trust and knowledge in the context of emerging climate-adaptive forestry policies" - by Guillame Peterson St-Laurent et al., 15 July 2019, Journal of Environmental Management
    ABSTRACT EXCERPT: ... We use the example of genomics-based assisted migration (within and outside of natural range) in British Columbia's (BC) forests to examine the relative roles of and interactions between trust in different forestry actors and knowledge of forestry in shaping public support for this new and potentially controversial management alternative. Our results, based on an online survey, reveal low public trust in governments and the forest industry combined with low levels of public knowledge about forest management. We find that individuals who are more trusting of decision-makers and other important forestry actors hold higher levels of support for assisted migration. Higher levels of forestry knowledge are linked with support for assisted migration within native range, whereas no knowledge effect is observed for assisted migration outside of native range. We discuss the implications of these observations and provide recommendations to more fully engage with the challenges of low levels of trust and knowledge in this context.

    Editor's note: In the Sci-Hub full text link, the term "assisted migration" appears 60 times in this article.

  • Should We Move the Whitebark Pine? Assisted Migration, Ethics and Global Environmental Change - by Clare Palmer and Brendon M.H. Larson, 2014, Environmental Values
    Editor's note: This paper excels in exploring the range of values from the deep-ecology "intrinsic value" of a species and its "wildness" to human-centered aesthetic values and humans prioritizing the suffering of individuals of "sentient" species over the extinction of a non-sentient species.

    ABSTRACT: Some species face extinction if they are unable to keep pace with climate change. Yet proposals to assist threatened species' poleward or uphill migration ('assisted migration') have caused significant controversy among conservationists, not least because assisted migration seems to threaten some values, even as it protects others. To date, however, analysis of ethical and value questions about assisted migration has largely remained abstract, removed from the ultimately pragmatic decision about whether or not to move a particular species. This paper uses the case study of the whitebark pine, a keystone species of sub-alpine habitats in western North America, to consider how particular cases of assisted migration may be ethically approached. After taking into account the value of species, wildness, place, ecosystems, culture and sentient animals, we conclude that, on balance, there appear to be good reasons to move the whitebark pine.

    EXCERPTS: ... The assisted migration of rust-resistant strains of whitebark pine may be the only way to preserve the species for the future. If we think that a species has some kind of intrinsic value or moral status, this is a presumptive reason in favour of moving it. This reason might be defeated if the whitebark pine was likely to be invasive in its new location, and to threaten native species, but this is extremely unlikely to happen. Indeed, for around sixty years, until relocated whitebark pine starts setting significant numbers of cones, it will remain exactly where we planted it. Even then, it will only propagate with a healthy nutcracker [bird] population in situ. Invasiveness is thus not a plausible reason to ressist relocation. In addition, whitebark pines, even before they start to set seeds that may be a useful source for high-altitude animals and birds, could provide ecosystem services such as retaining soil moisture, modifying soil temperatures, slowing the progression of snowmelt and helping to moderate flooding at lower elevations...

    The landscapes into which the whitebark pine would be relocated are not going to remain as they are. The species existing there will also be moving upward and poleward. New species will move in. Novel ecosystems will form (see Hobbs et al., 2013). Narratives of place will have to change, and human influence will extend across the changing landscape anyway. The relocation of the whitebark pine would not be the intrusion of an alien into a long-established and unchanging ecosystem, but a new member of a novel ecosystem with some potentially useful functions. ... Those who argue that species have moral status might deepen these narratives in terms of 'restitution' to species, such as the whitebark pine, that have been forced out of other locations by human activities. For while it's ethically difficult to make an argument that restitution or reparation can be directly owed to non-humans (with the possible exception of sentient animals), it may be possible to defend the view that the assisted migration of threatened species, where humans are responsible for the threat, is a kind of symbolic reparation.

    To conclude: we are not arguing here for anything as strong as a duty to relocate the whitebark pine. We do, however, consider that there are good reasons to do so, and few very strong ethical objections. Our claim is that if rust-resistant strains of whitebark pine can be clearly identified, then depending upon the outcome of economic- and feasibility-studies, and consultation at particular sites, there are likely to be places where the relocation of whitebark pine is ethically desirable... We have sought to be comprehensive in our taxonomy and analysis of values, partly as a model for future studies that must similarly attend to pertinent socio-ecological complexity, to include both biological nuance (e.g., the association here between whitebark pine and the Clark's Nutcracker) and social importance (e.g., the cultural values of the whitebark pine). We hope that this analysis of the particular case of the whitebark pine will help to provide the basis for future (and better) studies and applications of assisted migration.

    • September 2014 - "Time for Trees to Pack Their Trunks?", by Greg Breining, Ensia Magazine.
    EXCERPTS: ... When it comes to assisted migration to adapt to climate change, caution has generally trumped action. "Most places in the world are doing research but they're very reluctant to move into practice," says Sally Aitken. "We sold people so well on the 'local is best' that it's a big change to all of a sudden say, 'Well you might want to get your seed from somewhere else.'"... "The crux of it is that species are at risk because of climate change," says Dov Sax, deputy director with the Institute for the Study of Environment and Society at Brown University and member of a scientific group that studied assisted migration
        In some cases, the aim is to save a species with nowhere to go, stranded by elevation or manmade obstacles. In other cases, the concern is less for individual species than for the overall well-being of ecosystems. In northeastern Minnesota, for example, white spruce, paper birch and balsam fir may all but disappear in a warming climate. They will surely exist in profusion farther north. But can other tree species expand northward quickly enough to take their place? ... It may sound like a can't-lose. But in reality, assisted migration of trees is controversial — risky, some scientists say. For example, TNC offered to plant Michigan white pine on state and federal land in northeastern Minnesota, but both the U.S. Forest Service and state Department of Natural Resources declined, so the trees were planted on county land instead. "They are still, and rightly so, taking a conservative approach to moving things around," says Meredith Cornett.
        ... Some scientists and conservationists warn that mixing species will degrade "ecosystem integrity." But as Dov Sax points out, perhaps a fifth of the plant species in North America already hail from somewhere else. And the notion of a "balanced" ecosystem doesn't have much support in scientific evidence. "What we think of as ecosystems are transient — very few of the associations of species that we see now that make up an ecosystem would have been together at most points in time in the past," says Sax. "What we get is that maybe communities will be together for a few thousand years." Novel ecosystems — a hodgepodge of natives and exotics — can function, but how much worse or how much better than native assemblages is still a puzzle. "That's the kind of thing we don�t have a handle on," Sax says.
        ...When it comes to assisted migration to adapt to climate change, caution has generally trumped action. "Most places in the world are doing research but they're very reluctant to move into practice," says Aitken. "We sold people so well on the 'local is best' that it's a big change to all of a sudden say, 'Well you might want to get your seed from somewhere else.'"
        In Europe "most conservationists are quite conservative (what's in a name?) when it comes to introducing or translocating species," Sebastiaan Van der Veken, director of the natural area Regionaal Landschap Kleine en Grote Nete in Belgium, wrote in an email. "Even reintroduction of recently disappeared species or short-distance translocation is highly discussed. Most scientists in Europe think (or hope) creating robust networks and corridors will make it possible for species to migrate themselves. They even fear that putting assisted migration on the agenda will restrain policy makers from investing in these ecological networks 'because we can simply move species around when necessary.'"
        Meanwhile, as scientists debate, there's evidence that ambitious gardeners and commercial nurseries are stealing the march. Commercial plant nurseries are raising, selling and introducing hundreds of native forest plants far beyond their natural ranges — in effect pushing the northern limits of these trees, shrubs and wildflowers on average more than 600 miles, according to a study by Van der Veken. Not surprisingly, however, there is a bias toward pretty, popular and economically valuable species. "So it would be wrong to rely on these nurseries and gardeners alone to solve the biodiversity problem induced by climate change," Van der Veken wrote. "Scientists have an important role in making a framework for assisted migration, including screening of endangered species, translocation risk analysis and post-migration monitoring." Other scientists concur that the willy-nilly experimentation in the garden or backyard is unsuited to remaking something as long-lived and self-sustaining as a native forest.
  • "Under pressure: Conservation choices and the threat of species extinction" - by Robin Gretory et al., May 2021, Climatic Change
    EXCERPTS: Shifts in species ranges and viability introduced by climate change are creating difficult challenges for scientists and citizens. In many cases, the seriousness of threats to endangered species is forcing policy makers and resource managers to consider novel species protection strategies, either to complement or replace existing conservation approaches. This paper seeks to deepen understanding of public views on a range of conventional and novel management initiatives designed to protect species under the threat of extinction, based on results from an online survey conducted in the USA and Canada.... Results generally support the conclusion that, so long as a clear rationale is provided, there exists surprisingly widespread support for the adoption of novel management approaches to save threatened or endangered species even if this requires more intensive genetic and transformational interventions that are costly or ethically challenging.... Such novel climate-adaptive options are not without controversy, due to the ethical issues and ecological risks to which they give rise. For instance, assisted migration involves concerns regarding the transgression of natural boundaries (Aubin et al. 2011; Hancock and Gallagher 2014; Peterson St-Laurent et al. 2018) and may contribute to the introduction of invasive species, pests, or diseases (Dumroese et al. 2015; Park and Talbot 2012; Pedlar et al. 2012). Objective setting by triage also raises moral issues in terms of deciding which species are conserved, how these decisions are made, and by whom (Bottrill et al. 2008; Knight et al. 2019). Because of the risks and values-based thresholds inherent in these more interventionist management responses, segments of the public as well as experts may prefer to rely on status quo or business-as-usual conservation strategies, at times favouring non-interventionist policies that step back and let nature take its course (Hagerman and Satterfield 2014).
    "Responding to climate change in forest management: two decades of recommendations" - by Shannon M. Hagerman and Ricardo Pelai, October 2018, Frontiers in Ecology and Environment
    EXCERPTS OF "ASSISTED MIGRATION" (the term or its cognates appears 4 times in the paper and twice in the references): ... Considering the pace of institutional change that characterizes many resource management contexts, it seems likely that amended rules and legislation to enable potential transformative, unconventional practices like assisted migration (Klenk 2015) will unfold slowly and may be controversial (Figure 1). This potential for dispute relates to the often-overlooked role of values and worldviews in shaping preferences for transformative policies and management actions (Moore et al. 2014; Andrachuk and Armitage 2015). Put simply, new policies may be rejected outright for values-based reasons (Baron and Spranca 1997; Hagerman and Satterfield 2013), such as the position that humans should (or should not) intervene in nature. We there- fore strongly agree with Andrachuk and Armitage (2015), who similarly asserted that values should be taken into account when evaluating potential pathways for transformation.... The analysis presented here provides a systematically derived synthesis of two decades of recommendations for forest management in response to climate change. We offer an empirical basis for future comparisons of recommendations through time, as well as a reference for comparisons between scientific and practitioner perspectives....

  • "Expert views on biodiversity conservation in an era of climate change" - by Shannon Hagerman et al., February 2010, Global Environmental Change
    EXCERPTS (featuring "assisted migration"): Conservation scientists have responded with a range of adaptive conservation strategies. These include proposals for dynamic protected areas (Bengtsson et al., 2003; Rayfield et al., 2008) assisted migration (McLachlan et al., 2007; HoeghGuldberg et al., 2008; Richardson et al., 2009), and most prominently, the expansion of linked networks of static protected areas (e.g. Hannah et al., 2002; Hannah, 2008).... We pay particular attention to the interacting roles of (i) the history of debate about new policy proposals, (ii) the state of the science including uncertainty, (iii) the role of values and beliefs and (iv) policy windows. Below, we detail why these particular variables matter in this problem context and with respect to the purpose of this paper.
         All interviewees expressed the view that a paradigm shift in conservation practice was required to adapt to the impacts of climate change.... Assisted migration the deliberate translocation of an imperiled species from one location to another where it has not existed in recent history, is a notable relative exception (e.g. McLachlan et al., 2007; Richardson et al., 2009).
         ... Overall, eight respondents initially expressed opposition to assisted migration interventions (six affiliated with NGO, one government and one academic). However, over the course of discussion, all but one respondent noted that interventions such as assisted migration would be necessary given the impacts of climate change. The tension surrounding discussions both about assisted migration and triage principles for management and objective setting arguably reflect different perspectives on 'nature' and the role of humans within/outside of 'it'. On the one hand, the statement above by Expert 17 reflects the view that true 'nature' is something 'out there', and separate from human influence. By this framing, all human manipulation is 'intervention', seen as unnatural and potentially unethical. On the other hand, the statements of Experts 2 and 13 above reflect the perspective that nature is a co-produced, integral and linked component of society. Viewed through the lens of linked SESs, so-called 'interventions' such as assisted migration can be viewed as part of the evolution of management and changing means and objectives through time (however undesirable this may seem and noting the need for great caution in potential implementation). Combined, these responses reveal how different perspectives on nature can shape expressed preferences for management, which have the potential to influence policy design and implementation.
  • April 2010 - "The Value of Species and the Ethical Foundations of Assisted Colonization", by Ronald Sandler, in Conservation Biology.
    "... Many species are imperiled by the accelerated rate ofclimate change, often in combination with other anthropogenic stressors, and frequently anthropogenic barriers (e.g., urban and agricultural) prevent them from coping by shifting their geographical ranges (e.g., Hulme 2005; Parmesan 2006; Williams et al. 2007). Advocates of assisted colonization (or assisted migration) argue that helping species over these barriers is justified because it keeps them from going extinct, thereby preserving their value (e.g., Barlow & Martin 2004/2005; McLachlan et al. 2007; Hoegh-Guldberg et al. 2008). Therefore, the case for assisted colonization depends fundamentally on claims, both explicit and implicit, about the value of species. A complete discussion of assisted colonization needs to include assessment of these claims.... The paradigmatic cases of and candidates for assisted colonization discussed in the professional and popular literatures indicate. These cases include relocating the Quino checkerspot butterfly (Euphydryas editha quino) to higher elevations (e.g., Zimmer 2007; Hoegh-Guldberg et al. 2008; Marris 2008), the Florida torreya (Torreya taxifolia) to North Carolina (e.g., Barlow & Martin 2004/2005; Schwartz 2004/2005; Fox 2007), and the narrow-faced kangaroo rat (Dipodomys venustus) north of San Francisco (Berdik 2008). In each case, the aim is to prevent the species from going extinct, not to improve the ecological conditions of the recipient system. The ecological value of the species is not the basis for, and does not justify, the assisted colonization."

    ABSTRACT: Discourse around assisted colonization focuses on the ecological risks, costs, and uncertainties associated with the practice, as well as on its technical feasibility and alternative approaches to it. Nevertheless, the ethical underpinnings of the case for assisted colonization are claims about the value of species. A complete discussion of assisted colonization needs to include assessment of these claims. For each type of value that species are thought to possess it is necessary to determine whether it is plausible that species possess the type of value and, if so, to what extent their possessing it justifies assisted colonization. I conducted such an assessment for each of the predominant types of value ascribed to species: ecological, instrumental (including option value), existence, and intrinsic value (including interest-based, objective, and valuer-dependent intrinsic value). The vast majority of species, including several that have been proposed as candidates for assisted colonization, have much less value than is often presumed. Moreover, with respect to some types of value, assisted colonization would not fully preserve the value of the target species even if it were to keep the target species in existence. Therefore, the case for assisted colonization is significantly weaker and more qualified than its advocates often suppose. There may be exceptional species for which assisted colonization is well justified�and for this reason, case-by-case assessment is necessary — but in general the burden of justification generated by the ecological risks associated with assisted colonization is not met by the value potentially preserved by assisted colonization. This suggests that assisted colonization ought to have, at most, a very minor role in the portfolio of ecosystem management practices, even as it pertains to species conservation under conditions of rapid climate change.

    END OF VALUES SECTION (for assisted migration scholarly links)

  • "Agency launches long-term spruce, aspen treatment plan by Dennis Webb, The Daily Sentinel (Grand Junction, Colorado), 6 August 2016.
    EXCERPTS: Responding to habitat shifts resulting from climate change will be one of the considerations for the Grand Mesa, Uncompahgre and Gunnison national forests as the Forest Service embarks on a new forest treatment project over the next eight to 12 years. Its new Spruce Beetle Epidemic and Aspen Decline Management Response project is a response to about 223,000 acres where spruce have died from beetle infestation on the forests, and 229,000 acres that have been affected by what's called Sudden Aspen Decline, over a decade.
         The Forest Service expects mortality in spruce stands "to continue at relatively high levels for several years to come," according to the final environmental impact statement for the project. In 2009 the detection of new areas of aspen decline dropped considerably, but stands already affected continue to decline, and the Forest Service expects the aspen and spruce problems to be exacerbated in the future by climate change.
         While the new forest treatment plan is intended to also address other goals like reducing safety hazards such as falling trees and increased wildfire danger, improving forest resiliency is a key goal. That includes trying to make the forest resilient in the face of a changing climate. "In the climate change world, that's called adaptation measures — basically trying to adapt the forest to a changing climate," said Jim Worrall, a Forest Service forest pathologist who helped do the climate modeling. He said quite a few outcomes of the management response project "could help adapt the forest to a warmer and potentially drier climate."
         Worrall said where logging of beetle-killed spruce occurs, that could provide an opportunity for regenerating those acres with more aspen, or other trees more tolerant of an expected hotter, drier climate, such as Douglas fir, ponderosa pine and blue spruce. "I think at first it's going to be baby steps because people are a little bit cautious, and reasonably so, about completely changing a (forest) cover type," he said. Where there's spruce-fir forest, it might be crazy to start planting pinon-juniper now, even if models say it would be good pinon-juniper habitat by the end of the century, he said.

  • Also by Dennis Webb, 6 August 2016, "Cycle of decline: Estimate portends big changes in makeup of forests".
         EXCERPTS: Lovers of the local high country could find a recent projection of a warming world's impacts on area forests to be chilling. By 2060, according to a U.S. Forest Service estimate, almost all of the Uncompahgre Plateau would no longer be able to sustain growth of new aspen and spruce, meaning that the plateau could be virtually aspen- and spruce-free by century's end after the remaining trees die. On the southern and eastern fringes of Grand Mesa, aspen also could see sizable losses of suitable habitat by 2060, with spruce habitat largely slipping into a threatened category across the mesa, meaning the future climate isn't favorable to sustaining it.
         The modeling used by the Forest Service found that 52 percent of current aspen distribution across the forests would be in the lost habitat category by 2060, and 42 percent in the threatened category, "meaning it is conceivable that 94 (percent) of current aspen distribution may not continue into the next century," the Forest Service says in its final environmental impact statement for the project, released earlier this year. Aspen habitat generally would be lost at low elevations, especially on south-facing slopes, with the western West Elks also sharing in that habitat loss. Some of that habitat loss could be offset by newly emerging habitat at higher elevations. But Samantha Staley, a Forest Service planner, says while the climate may shift to support the species at a higher elevation, that doesn't mean that other ecological components necessary to support the species will be present. Some higher elevations may not be suitable thanks to things such as poor soil conditions or rocky scree slopes. The model projects a 22 percent loss of current spruce distribution, and that 58 percent of distribution will become threatened, meaning that 80 percent of current distribution may not continue into the next century.
         The model is based on an assumption of a continuing warming trend on the forests. The statement says temperatures are expected to rise 5.4 to 7 degrees by 2040-60. Higher temperatures could foster more spruce beetle outbreaks, further stress trees because of increased drought and result in more damage from wildfire. "I think what those maps show is stunning,"Zukoski said. "I think those kind of maps are extremely helpful because they permit people to see in their areas, places that they care about in their backyards, what the world's going to be like for their kids and grandkids, and for themselves if they live long enough. I think giving people that picture over that longer term really helps them understand how dramatic the impacts of climate change could be if we don't work darn hard to get a handle on it."
         Meanwhile, a 2006 model created by researchers led by Gerald Rehfeldt, who worked at the Forest Service's Moscow Forestry Sciences Laboratory in Idaho before retiring, projected a 47 percent drop in suitable spruce habitat in the western United States in the decade around 2060, and a 72 percent loss by 2090. The Forest Service statement says that for the forests, that model was rebuilt using local data, more "topographical predictors," newer global climate models and carbon scenarios, and higher-resolution climate data. Its resulting projections are an average from three climate models and three greenhouse gas emission scenarios. "These are models, which necessarily include some amount of error," Staley said. She said it's based on the best available information today, and the Forest Service understands the science will be a lot better in a decade. "We have to look at it as it's not the gospel, but it's the best available scientific information that we have today about where vegetation may be headed in the future," Staley said.
         Jim Worrall, a forest pathologist with the Forest Service�s Rocky Mountain Region 2, which includes Colorado, said Rehfeldt worked with him and others to localize his methods, and they developed a model for 13 tree species in southwest Colorado, including spruce and aspen. Worrall said one of the biggest uncertainties pertains to the climate models, because there are so many models and carbon scenarios to choose from. He said the forest-habitat predictions the Forest Service came up with concern him and he hopes they're wrong, but they're the best idea researchers now have of what the future holds. "It's really a very objective process. There's really no subjectivity in the model development," he said. Interpreting the results to make them simple and easy to digest can be a little subjective, he said. "But we've been pretty conservative in that," he said, adding that the predictions are based on what the models are telling researchers, and those models are built on a lot of data.
         Staley said the agency is compelled to use that science in its planning and efforts to manage sustainably into the future, and current research acknowledges that warming will result in shifting of not just animals but trees in terms of habitat. "The environment is changing and that's why we're using as much information as we can to make the best decisions," she said. Forests are always changing, thanks to factors such as insect infestation and wildfire, and cycles such as aspen thriving first in disturbed areas and later being succeeded by other types of trees. But now the Forest Service is learning more about how that's happening in the context of "pretty rapid climate change," and what the forest may look like in that context, Staley said.
         While every generation sees a slightly different version of a forest, future forests may be ones that people have never seen locally, she said. Rather than a mid-elevation forest shifting back and forth from aspen to spruce, it may shift to oakbrush. "And that's a new shift," she said. Oakbrush and mixed-mountain shrubs cover about a quarter of the Uncompahgre Plateau now.
         [Jim Worrall] said of the modeling's findings, "I think we need to plan for the worst and hope for the best, is what I suggest. But most likely even if the models are a little off, we're going to be looking at very different conditions in the future for our children and our children's children than we have now."

  • "The assisted migration of western larch in British Columbia: A signal of institutional change in forestry in Canada? by Nicole L. Klenk and Brendon M.H. Larson, Global Environmental Change 2014.
    EXCERPTS: Based on 46 interviews with policy actors across Canada, our results suggest that the deployment of the first assisted migration policy in Canada successfully avoided the controversy surrounding the idea in the scientific community by changing the scientific discourse associated with best forest management practices. The shift from an ecological discourse to a genetics discourse over forest policy in British Columbia signals what we might expect in future forest adaptation policy development in Canada.
        Clearly, a genetics characterization of forests looks back to the distant past for guidance in future 'climate change fitness of species'. This represents a major conceptual shift, which significantly affects the temporal and spatial scales on which forest management planning occurs. This shift can be characterized, furthermore, by the deployment of new normative goals for forest management: rather than trying to recreate current forest composition and functions, the values and norms guiding forest management from a genetics perspective seek to accelerate forest transition to the future, to a 'climate resilient' state. This normative shift has real material consequences, such as enabling the movement of western larch 1000 km north of its current distribution, sidestepping the issue of its ecological appropriateness in the recipient ecological community, because from a 'climate fitness' perspective, western larch may eventually migrate to northern BC.
        Thus given the genetical frame structuring the AM policy coordinative discourse, we argue that there is a major shift in the cognitive and normative content of ideas at the program level. However, when we analyzed the communicative discourse on western larch AM policy, we found that concerted efforts were taken by policy developers to downplay the significance of this program change in their communication to the public. To begin, educational and training outreach activities stressed the low risk associated with population range expansion, as the following interviewee explains: "We are very open and inclusive in talking about AM. I talk about the risk of action and inaction and more importantly the difference between the various forms of AM. We are very clear that we are not testing or interested in exotic translocations."
        To sum up, our analysis suggests that policy analysts, forest geneticists and policy implementers in the BC Tree Improvement Branch characterized forests so as to highlight and diffuse an evolutionary theory of forest ecosystems that is tied to a new set of norms and values associated with a humanistic philosophy that are highly controversial in the conservation community—yet which, in turn, are signals of major institutional change in forest policy in BC. . .  Our results suggest that the deployment of the first AM policy in Canada has successfully avoided the philosophical debates on AM in the conservation scientific community by changing the scientific discourse associated with best forest management practices (i.e., from an ecological point of view to a genetics point of view) and this discursive shift may signal what we might expect in future forest adaptation policy development in Canada.

    Editor's note: See also Nicole L. Klenk, 2015, "The Development of Assisted Migration Policy in Canada: An Analysis of the Politics of Composing Future Forests", published in Land Use Policy. For a superb example of Canadian foresters utilizing the best communication skills in reported news stories, see the 14 June 2015 "Canadian scientists help trees adapt to changing climate". Here is the lead quote by researcher Sally Aitken, "Trees are adapted to historical climate and the climate's moving out from under them. We're using genomics to generate answers more quickly than they can." Here is her closing quote: "We have changed things to the point where we really have to foster the future of the environment and the forest. I think it would be very foolish and irresponsible to say, 'Let nature take care of itself.'" As well, see Aitken quoted in 29 January 2014 news story: "New genes for old forests as Canada warms": "So my research is focused on the best way to better match trees with new and future climates, to assist the movement of that genetic material through reforestation." Aitken is also quoted here (for Whitebark Pine, 18 September 2014, NYT): "For Trees Under Threat, Flight May Be Best Response".

    See also; "Opinions on strategies for forest adaptation to future climate conditions in western Canada: Surveys of the general public and leaders of forest-dependent communities", 2014, Reem Hajjar et al., Canadian Journal of Forest Research.

  • REVIEW ARTICLE IN FORESTRY ADAPTIVE MANAGEMENT 2019: "Adaptation strategies and approaches for forested watersheds", 2019, by P. Danielle Shannon et al. [all 8 authors are associated with Northern Institute of Applied Climate Science] in Michigan, Climate Services, February 2019.
    Editor's note: This 2019 review paper lays out the adaptive management process developed by NIACS over the years and reports examples of two user-groups in Massachusetts and Minnesota, only one of which (Knife River adaptation demonstration in Minnesota) chose to use elements of "assisted migration" as a management tool. Ricciardi and Simberloff 2009 is cited multiple times for its cautionary perspective, "Assisted Colonization Is Not a Viable Conservation Tool." It is unusual for a forestry paper to give this degree of credence to a perspective grounded not in traditional forestry but in conservation biology. On the plus side of using research to support actual and pragmatic user decisions, the NIACS approach in advising landowners on forestry climate adaptation is grounded in assisting management discussions on climate risk, management values and goals, and site-specific tactics — without staff or advisors making any recommendations along the way. This summary of what the group has been doing over the years is highly recommended. Pages 6-7 expressly deal with assisted migration as one possible tactic for climate adaptation.

    EXCERPTS: ... The overarching goal of this work is to help individuals and organizations within a diverse management community clearly articulate their decisions and how they have intentionally considered climate change, risk, and adaptation in their management.... Two major challenges in the practice of climate adaptation are (1) translating broad adaptation concepts (Millar et al., 2007) to specific, tangible actions (Swanston et al., 2016), and (2) clearly and explicitly identifying the adaptation intent of an on-the-ground action. We de- veloped an adaptive management process and step-by-step Adaptation Workbook in 2012 (Swanston and Janowiak, 2012; Swanston et al., 2016) that helps practitioners identify adaptation actions that address perceived climate threats and opportunities in pursuance of their stated management objectives. We also developed a series of adaptation menus that help people link their actions to broader adaptation stra- tegies that align with their values and objectives, generally define success, and explicitly identify intent (Swanston et al., 2016). Each menu addresses a different resource area, using relevant and appro- priate terms, strategies, approaches, and example tactics. Although the menu concepts focus on adaptation to climate change, the ideas are rooted in fundamental principles of natural resources management (Creed et al., 2011) and may also provide co-benefits to various conservation efforts and greenhouse gas mitigation goals. Critically, the menus are not guidelines and do not make recommendations. They instead represent numerous approaches to resource management that are often complementary, but always chosen by the user as they deem appropriate.... Importantly, the Adaptation Workbook and menus do not compel or influence natural resource managers to change their ecosystems or adopt new practices; instead they help mangers make intentional, climate-informed decisions best suited to their objectives, constraints, and perception of climate risks and opportunities.
         ... Strategy 4: Facilitate forest ecosystem adjustments through species transitions Approach 4.1: Favor or restore native species that are expected to be adapted to future conditions. Approach 4.2: Establish or encourage new mixes of native species. Approach 4.3: Disfavor species that are distinctly maladapted. Approach 4.4: Introduce species that are expected to be adapted to future conditions. Approach 4.5: Move at-risk species to locations that are expected to provide habitat.

  • "What is Novel About Novel Ecosystems: Managing Change in an Ever-Changing World", 2015, by Amy Truitt et al, Environmental Management
    Editor's note: This 2015 paper is quoted at length because it places "assisted migration" within a tri-fold management regime which the future will necessarily bring to ecological restoration and conservation biology.

    EXCERPTS: While over the past several hundred years most landscapes have been altered by anthropogenic activities, and in many cases outright habitat destruction, the terminologydescribing the resulting ecosystems is inconsistent and inadequate for effective cross-sectoral management. Due to the dynamic nature of ecosystems and the varied disciplines that have evolved in the Anthropocene to study them, it has proven challenging to find a universal language that defines 'novel' ecosystems (e.g., Milton 2003; Hobbs et al.2013;Morse et al.2014; see Table1). Equally challenging is the development of a common set of metrics to quantify ecosystem changes and the functional impacts resulting from those changes (Murcia et al.2014). Neutral, unambiguous, and consistent terminology with a framework for categorizing novel ecosystems is needed to classify, describe, and manage these systems. Such classification can facilitate decision-making in a landscape of diverse management objectives and variable social perceptions around novel systems (but see Murcia et al. 2014).
         Priorities for and approaches to managing novel ecosystems vary based on perspective of the scientists, managers, and policy-makers along the anthropocentric�biocentric continuum. Practitioners with a biocentric perspective are more concerned with impacts that novel ecosystems have on biodiversity, community composition, and ecosystem function, while those with an anthropocentric perspective may be more interested in how novel ecosystems will affect ecosystem services on which humans depend. Management approaches to novel ecosystems range from strategies that actively promote the ability of novel ecosystems to achieve conservation goals (Zedler et al.2012), to active prevention of novel ecosystems (Stromberg et al.2009). These approaches range from accepting irreversible landscape alterations and promoting and accounting for ecosystem services provided by novel assemblages (Melo et al.2013) to active prevention of native species and ecosystem loss (Willis et al.2010; Lindenmayer et al.2008) or land restoration to prioritize ecosystem functions and processes in certain novel ecosystem scenarios (Hobbs et al.2009). On some sites, assisted migration, such as purposeful ymoving species to more climate suitable habitat (Richardson et al.2009) has been recommended. Some practitioners suggest that novel ecosystems should be recognized as achieving conservation goals and remain where they arise, rather than be managed (Hobbs et al.2006;2011; Martinet al.2012). Others suggest eliminating the term 'novel ecosystems' as it could be a hindrance to ecologically sound restoration efforts (see Murcia et al.2014). Acknowledging the diverse perspectives may facilitate compromise and development of mutually acceptable management approaches. The term itself may be useful in delineating to the public and policy-makers the far-reach-ing effects of anthropogenic activities on proximal and remote ecosystems (e.g., Blight and Ainley 2008; Holt-grieve et al.2011), which may facilitate greater consensus on appropriate management strategies.
         Here we ask whether novel ecosystems are, in fact novel, or whether these systems are a manifestation of ongoing evolutionary change in ecosystem and species assemblages. Given the many definitions of novel ecosystems, we present previous and current definitions, offer a working definition for use in management decision-making, and differentiate the frameworks surrounding each to organize possible management approaches to novel ecosystems. Finally, we propose a categorization scheme and framework (Figs.1,2) for managing novel ecosystems now and in the future.
         We introduce a framework for identifying how to manage novel ecosystems with three alternative directives to address the spectrum of challenges posed by these ecosystems. The directives include managing against, tolerating, and managing for novel ecosystems and can be directly tied to management objectives (Fig.2). We provide examples and discuss the social, economic, and ecological advantages and disadvantages of each.
         There is a threshold in some affected ecosystems at which point either managing against or tolerating is no longer an option (Fig.1). Although this alternative is less common and may be more controversial, we expect the need to manage for novel ecosystems and the services they have evolved to provide will become more prevalent in the future under changing climatic conditions and increased globalization. Where species have been lost or have severely declined and restoration has been unsuccessful, or where land use change has been intensive, managers may find that managing for novel ecosystems provides the only or best alternative. . . Other examples of managing for novel ecosystems include the plethora of introduced plant species that have become important in the agricultural sector; assisted migration of more climate-suitable tree species to managed forests (Gray et al.2010; Duveneck and Scheller 2014); managing non-native species assemblages in parks (e.g., Underwood et al.2004); non-native species used for recreational purposes (e.g., Crawford and Muir 2008; Britton et al.2011) and non-native species for conservation (Schlaepfer et al.2010; but see Vitule et al.2012for rebuttal).

  • "The Fight to Unmuzzle Canada's Scientists" by Stephen Buranyi, Motherboard 27 August 2015
    EXTRACTS: Dr. Phil Burton's work was also far outside what he thought the government might consider hot button. Dr. Burton, a professor at the University of Northern British Columbia, had previously spent 20 years with the Canadian Forest Service studying boreal forests in northern Canada. He recalls getting permission from Ottawa to attend a conference, but his permission came with a paradoxical request: "The conference was a series on disturbance dynamics in boreal forests, and the theme that year was climate change. I was told not to talk about climate change or forestry impacts. Well that's the whole point of the conference!" he said. . . "I work with government scientists every day, literally every single day, and they've just had their legs completely cut out from under them," said Alana Westwood, a graduate student in biology at Dalhousie University.
        The Liberal Party of Canada has indicated it's interested in staking its claim early as the party of science. In May, Liberal MPs introduced a motion to "un-muzzle" Canadian scientists and introduce a parliamentary science officer, and a month later Liberal Leader Justin Trudeau announced that if elected he would review some of the legislative changes to environmental acts under Harper. The Liberal motion was largely symbolic; the Conservative majority sunk it fast. But it was a start, and the campaign promises remain on record.
        Editor's note: A few months after this report was published, the Liberal Party did become the majority party, and Justin Trudeau did oust Stephen Harper from the office of Prime Minister. The muzzles are gone!

  • "Conservation Biology: The End of the Wild" by Emma Marris, Nature 12 January 2011, 469:150-52
    "Climate change means that national parks of the future won't look like the parks of the past. So what should they look like? . . . [National Park Service director Jonathan] Jarvis has suggested the possibility of moving species outside their native ranges to give them a better chance of surviving — just not right away. "The big point here is that we are willing to face these questions," he says. "We are not afraid to talk about them."

    SEE ALSO an Dec 2010 online interview with NPS Director Jonathan Jarvis on climate change and park management, including "assisted migration".

  • "Defining Migration" chapter of Brian Keel's PhD thesis.
    Brian Keel intentionally coined the term "assisted migration." This short chapter will be useful for those engaged in considering whether "assisted migration" or "assisted colonization" is the best term for the kinds of conservation actions now beginning to be considered. Editor's note: The historical sequence of controversy over terminology can be accessed here: "Assisted Migration or Assisted Colonization: What's in a Name?"

  • "Assisted Colonization: CBC Radio Interview"
    A terrific AUDIO exploration of the controversy, which aired 24 July 2008. Part 1 is the supportive side, via an interview with Prof. Camille Parmesan. Part 2 is an interview with an invasive species researcher that is very critical of the idea. Part 3 is a not-to-be-missed radio spoof of the idea.

  • "Tending to Our Rambunctious Garden" Q&A with journalist Emma Marris, OnEarth 28 September 2011
    Emma Marris's 2011 book, Rambunctious Garden, has "Assisted Migration" as the topic and title for chapter 5. The Q&A linked above is an excellent short introduction to the reach of this book in highlighting the shifting norms and values in conservation biology and land management today. Assisted migration advocate Connie Barlow posted a positive review of the book on Amazon: "Rewilding, Assisted Migration, Ecological Restoration, and More". There's also an excellent dot-Earth video interview of Marris on youtube.

  • "The Age of Man Is Not a Disaster" - Op-ed by Emma Marris, Peter Kareiva, Erle C Ellis, New York Times 7 December 2011
    EXCERPT: "We can accept the reality of humanity's reshaping of the environment without giving up in despair. We can, and we should, consider actively moving species at risk of extinction from climate change."

  • "Guardian Angels" article by Janet Marinelli, Audubon Magazine, May/June 2010.
    In-depth exploration of "the biggest controversy in contemporary conservation science." Engagingly written for both a popular and professional audience, journalist Marinelli draws from her interviews with leading scientists, horticulturalists, and activists to present the core arguments for and against assisted migration. A site visit to an endangered plant breeding facility (the Atlanta Botanical Garden) is paired in the article with Marinelli's eye-witness description of "eco-vigilante" action, when the loose-knit citizens group Torreya Guardians intentionally planted into forested landscapes of mountainous North Carolina 31 seedlings of the highly endangered Florida Torreya — an assisted migration of some 400 miles northward of historically known native habitat.

  • "Taking Wildness in Hand: Rescuing Species" article by Michelle Nijhuis, Orion Magazine, May/June 2008.
    A lengthy and elegant feature article that explores the human side of the controversy over assisted migration, with Torreya taxifolia providing the focal point, pro and con, and with actions by the citizen group Torreya Guardians stirring the brew. Comments page accessible through the foregoing link to Orion magazine.

  • 2009 book highlights ASSISTED MIGRATION controversy, Heatstroke: Nature in an Age of Global Warming, by Anthony Barnosky (Island Press)
    Publisher's press release excerpt: Unfortunately, both assisted migration and Pleistocene rewilding would lead to managed ecosystems — the antithesis of wilderness. Just as we manage fisheries to preserve an important food source, we will have to give up some wildness in order to preserve species. "We can't protect all three faces of nature — ecosystem services, like clean water and fisheries; species diversity; and the feeling of wilderness — without somehow separating those three different concepts of nature and working with each one of them differently," [the author] says. "All can be complementary, but you have to do different things for each one. I think there are people who are quite happy to settle for one or two of those, but my personal philosophy and feeling is that we can have all three faces of nature." [The author] foresees two types of preserves, for example: species preserves to protect a species or assemblages of species, but requiring heavy management; and wildland preserves that retain ecological interactions without the influence of humans — the feel of wilderness — but which will see changing species and even extinctions.

        The SUNY College of Environmental Science and Forestry launched in April 2014 Move It?, an online questionnaire that scores the suitability of user-defined species (candidate taxa) for assisted colonization. Questions are divided into three main categories, following Hoegh-Guldberg et al. (2008): (1) need for assisted colonization, (2) technical feasibility of assisted colonization, and (3) biological/ socioeconomical costs versus benefits of assisted colonization.

    Move It? is also a growing database of user-submitted scores, which can then be used to compare candidate taxa and guide decisions about the use of assisted colonization in practice. Although primarily developed in the context of climate change, Move It? can be used to evaluate any proposal to translocate organisms outside their current range. Take the Survey!

    Award-winning animated video excerpts the allegorical tale by French author Jean Giono, 1953.

    This is the mythic story to inspire all of us — conservation biologists, forest managers, and involved citizens — to pull ourselves out of despair over the looming impacts of climate change and get on with the great work of planting (and moving!) trees.

  • Wikipedia entry
  • Video (in full) on youtube
  • DVD via Amazon
  • "The true meaning of life is to plant trees,
    under whose shade you do not expect to sit."
    — Nelson Henderson


  • "Commercial trade of federally listed threatened and endangered plants in the United States" (abstract) by Patrick D. Shirey et al., Conservation Letters Sept/Oct 2013, pp. 300-316.
    Note: This paper clearly establishes the legality of non-commercial translocations ("assisted migration", "assisted colonization") of endangered plant species in the USA. The voluntary efforts of citizen-naturalists in Torreya Guardians (assisting the northward movement of Torreya taxifolia) are used as a key example of such legal practices.

    EXCERPTS: "a listed plant could be purchased in one state and then transported to another state without violating the ESA, so long as the plant was taken from and planted on property not under Federal jurisdiction, such as private property. Furthermore, the ESA does not prohibit an individual from giving listed plants as a gift to someone in another state so long as a change in plant ownership is not in the pursuit of gain or profit." . . . In the United States, the structure of the Endangered Species Act, coupled with inadequate funding for endangered plant conservation, has encouraged citizens to undertake plant conservation, especially for charismatic plants threatened by climate change. For example, the Torreya Guardians have obtained plants and seeds of Florida torreya (Torreya taxifolia), and moved seedlings and saplings to the southern Appalachian Mountains, outside of the species' historic range (McLachlan et al. 2007; . . In contrast to accepted ex situ conservation practices (Haskins & Keel 2012), the Torreya Guardians established private experimental populations on the property of cooperative landowners to help preserve the species outside of its historic range because of its decline, lack of federal funding, and the availability of privately owned and commercially available plants and seeds. . . Finally, under U.S. federal law, citizens who move a listed plant are not constrained by the same assessment process as the federal government — their actions are legal under the ESA without a review of their plans. MORE EXCERPTS available in PDF. See also "Scientific American blog" on this topic (July 2013).

    Note: Because the Shirey et al. paper established the legality of Torreya Guardian actions "rewilding" an endangered conifer tree (Torreya taxifolia) far north of its climate-stressed "critical habitat," activist Connie Barlow recorded in November 2013 a 75-minute VIDEO BLOG (right), posted on Youtube, to summarize the group's learnings to date.

    Note: To go directly in the video to the importance of the Shirey et al. paper, click here, or click on the "Show more" link below the Youtube caption and see the full table of contents of the video, hotlinked by time codes.


  • "Regulate Trade in Rare Plants" by Patrick D. Shirey and Gary A. Lamberti, Nature 27 January 2011
    A groundbreaking "Comment" paper in one of the top science journals combines data analysis of 753 threatened or endangered PLANTS in the USA with policy and legal analysis of the as-yet largely unregulated trade in seeds and seedlings cultivated in private gardens and nurseries outside of the official native habitat. A very readable and thought-provoking exposition of pros and cons of business as usual, now that climate change is motivating conservationists (individually and in groups outside of government) to consider whether the imperiled plant species that they love might benefit from, or even require, their assistance ("assisted migration") — given that governmentally agencies are still hesitant to (and in some cases, prohibited from) expanding locations for conservation programs beyond so-called native range. The work of Torreya Guardians is highlighted, including a 2010 revision in the official ESA management plan for Torreya taxifolia, directing plan managers to attempt to coordinate activities with Torreya Guardians, where possible. The authors conclude: "Although the redistribution of plant species around the world is nothing new, the ease with which people can now obtain and transfer specimens is unprecedented. This, combined with a growing interest in assisted colonization, makes it more important than ever for federal and local governments to wrest control of illegal Internet trade, develop a policy for hybrids and ensure that genetic diversity is considered when propagating plants. 3 pages in PDF for purchase online.

    News articles on this paper: in Science Daily; Los Angeles Times.

    2012 poster by Shirey et al., 2012 Ecological Society of America's Emerging Issues Conference:

  • "Advising Noah: A Legal Analysis of Assisted Migration", by Julie Lurman Joly and Nell Fuller, 2009, Environmental Law Reporter
    ABSTRACT: Climate change will likely lead to dramatic transformations of habitats critical to many species. One proposed solution to this problem is assisted migration. No federal agency has yet developed any rules specifically regarding assisted migration in response to climate change. However, the existing laws, regulations, and policies do provide guidance that would affect any federally sponsored or permitted assisted migration program. This Article examines those laws, regulations, and policies currently in place that may challenge or facilitate assisted migration programs. Given this legal structure, we find that assisted migration is a legal option on most federal lands under certain circumstances. Federal programs examined are: National Park Service Lands, National Wildlife Refuge System, Multiple Use Lands, National Forests, BLM Lands, Alaska National Interest Lands, Wilderness Areas, Military Lands; also, policies on Endangered Species and Invasive Species.

    EXCERPTS: Assisted migration is simply the action of picking up and moving certain individuals or populations of species that either cannot or will not be able to migrate on their own in response to the rapidly changing climatic conditions expected over the next several decades.... Assisted migration efforts may also include the less invasive method of creating new migratory corridors through which species could migrate independently.... To a large extent, the legal viability of such a program will depend on where the species are moved to, which species they are, and who will do and/or fund the moving. We will address each of these issues in turn.

    EXCERPTS "FEDERALLY THREATENED AND ENDANGERED SPECIES": When a species being considered for assisted migration is listed as endangered or threatened under the ESA, many additional legal considerations arise. Unless permitted, picking up an endangered species and removing it from its home range is certainly a "take" within the meaning of Section 9 of the ESA and could "jeopardize the continued existence" of the species within the meaning of Section 7. However, both of these concerns may be overcome if the FWS can be convinced that the species will ultimately benefit from this drastic action. Assisted migration programs involving any federal agency that may affect any federally listed species will require a consultation with the FWS under Section 7 of the ESA. There is precedent for the FWS to initiate or approve similar actions. For instance, in 1986, all of the remaining wild condors were removed from the wild and bred in captivity. The results of this project have been the ultimate release of the raised chicks, slow rehabilitation of that population, and drastically improved understanding of condor biology. Assisted migration efforts could be treated similarly. The DOI has "broad power to conserve ... species." Furthermore, the ESA contains an affirmative obligation to use "all methods and procedures which are necessary to bring any [listed] species to the point at which the measures provided in this [act] are no longer necessary." Assisted migration could certainly fall within that rubric.... It is likely that in the future, assisted migration proponents could make the argument that global climate change has irrevocably altered or destroyed the primary habitat of the species with which they are working. While assisted migration of listed species is fraught with legal complications, their status renders them uniquely poised to be assisted migration beneficiaries.

    EXCERPTS "INVASIVE SPECIES": As many scientists have already suggested, assisted migration could potentially lead to a host of problems. No one knows when a threatened species will become a noxious invader upon being relocated. Species could become invasive and overwhelm the ecosystem into which they are introduced. A good example of this phenomenon is the black locust tree, which is native to the Appalachian Mountain region. [The tree] handily escaped groves that were planted on farmland further north. From New York to Wisconsin, colonies of black locust are pushing aside native plants — in some cases, rare endemic communities. Worse yet, this is happening right where you'd want to move the tree — several hundred kilometers north of its current distribution, where climate models predict it will thrive in 100 years. It is therefore a very real possibility that assisted migration efforts could lead to relocated species becoming invasive and outcompeting native plant or animal communities. It is also possible, however, that relocated species will pose no threat to the ecosystem into which they are introduced. We have been faced with the problem of exotic invasive species for over 100 years and have developed a large network of laws and policies to avoid problems. These laws may make relocating species as part of an assisted migration program much more complicated.

    EXCERPTS "CONCLUSION": Scientists, policymakers, and land managers may have to come to a new understanding in the coming years of what is a native versus non-native species. Already the term "neo-native" is coming into use to define a species that was not historically part of an ecosystem but, because of shifting climate patterns, may now be considered native. Such a new understanding will likely eventually result in new agency policies. Until that happens, the existing legal structure and case law are all that can guide us. Given this legal structure, as we have defined and interpreted it, we find that assisted migration is a legal option on most federal lands under certain circumstances. All federal agencies have legal obstacles in place that could hinder assisted migration efforts, but no agency has an outright prohibition. The NPS is the most conservative regarding the possibility of assisted migration, due to its focus on natural focus and native species. The other agencies seem to have greater legal flexibilities to attempt assisted migration efforts.... Therefore, while future legal and policy changes are likely to further facilitate assisted migration, it is a tool that is currently legally available to all federal agencies. Understanding the legal realities will enhance the possibility of assisted migration efforts actually being implemented and effecting on-the-ground species conservation.

    "Biodiversity on the Brink: The Role of 'Assisted Migration' in Managing Endangered Species Threatened with Rising Seas", by Jaclyn Lopez, 2015, Harvard Environmental Law Review.

    Extract: However, a plain reading of the ESA reveals the Service has ample authority to help species thrive in new, climate-changed environments through active or passive assisted migration.... Furthermore, there are many examples of successful experimental populations, and the International Union for Conservation of Nature has stated that assisted migration may not be more risky than reintroduction and that ecological risks may be effectively mitigated through proper planning. Two studies found that a majority of scholarly articles addressing assisted migration support its use and that it is the fourth most-cited climate adaptation strategy. This Article follows suit and argues the Service has a responsibility under the Endangered Species Act to use passive and active assisted migration as a means by which to buy species the time and space they need to adapt.

    "Endangered Species Act to the Rescue? Climate Change Mitigation and Adaptation Under the ESA", by Olivia Bensinger, 2017, NYU Environmental Law Journal.

    EXCERPT: Importantly in the era of climate change, the definition of critical habitat also allows the FWS to designate "target land areas for future migrations." ... While the original intent of the ESA is to preserve species in their original habitat, and while translocation might, on first glance, look like a "take," there may soon be a time when there is no other choice. Under Section 10(j) of the ESA, "[t]he Secretary may authorize the release . . . of any population . . . of an endangered species or a threatened species outside the current range of such species if the Secretary determines that such release will further the conservation of such species." This Section allows the Secretary to designate experimental populations to test how translocation might affect a species or ecosystem before authorizing the practice for a wide swath of species. FWS "[r]egulations interpreting this provision allow for the use of habitat outside a species' historic range when the 'primary habitat of the species has been unsuitably and irreversibly altered or destroyed.'" ... The ESA may have been written in 1973, but it has what it takes to protect species from the ecological problems of the twenty-first century. This requires only that we read the ESA, and act pursuant to it, in light of our changing world.

  • U.S. Fish & Wildlife Service "Internal Discussion Draft: Rising to the Urgent Challenges of a Changing Climate: Strategic Plan for Responding to Accelerating Climate Change in the 21st Century". Draft of 12 December 2008.
    "We will review, identify, and work to revise all elements of the Service's legal, policy, and regulatory framework necessary to support effective adaptive responses to changing climate. We will place particular focus on developing necessary new policies (e.g., assisted colonization) and needed revision of existing policies (e.g., what constitutes native, invasive, or exotic species?)." p. 15 "Novel conservation and recovery actions, such as assisted colonization, will be developed and implemented to protect acutely climate-vulnerable species." (p. 16)

  • "Climate Change Science Compendium 2009" by United Nations Environment Program (UNEP). September 2009
    Massive new report that goes beyond the usual IPCC report to make clear how the likely adverse effects of climate change are now thought to be much greater than even the IPCC reported. The section on "Management" contains a subsection on "Assisted Colonization" (p. 46 of the report; p. 4 of the PDF download), that includes these statements: "The reality of a rapidly changing climate has caught many natural-resource managers and policy-makers unprepared. Large-scale translocations might now be needed. Consequently, the conservation community needs to move beyond the preservation or restoration of species and ecosystems in place as the correct approach." and "Assisted colonization will always carry some risk, but these risks must be weighed against those of extinction and ecosystem loss. Already some regions of the Earth such as the Arctic are experiencing high levels of warming. Many others will experience unprecedented heat within the next 100 years, as well as altered precipitation and ocean acidity. The future for many species and ecosystems is so bleak that assisted colonization might be their best chance. These management decisions will require careful thought and will need to be backed up by detailed scientific understanding if they are to succeed."

  • "Species Conservation, Rapid Environmental Change, and Ecological Ethics" by Ben A. Minteer, The Nature Education Knowledge Project 2012
    EXCERPT: "Rapid, large-scale environmental changes are forcing conservationists to consider innovative and often controversial tactics for protecting species in this century, tactics that raise significant ethical and value-laden questions. Given what we already know about changes in species' ranges and abundances in the face of global climate change, it is inevitable that conservation in the post-preservationist era will require more interventionist conservation policies, leading to debates regarding risks, benefits, and likely success of novel practices such as managed relocation."

    See also Minteer's "Restoring the Narrative of American Environmentalism", January 2013, Restoration Ecology.

  • VIDEO: Assisted Migration and Invasive Species: Exploring an Ethical Dilemma" by Jay Odenbaugh, 2013, at U.S. Forest Service conference on assisted migration (38 min)
    VIDEO: (summary) "According to many, we are subject to two duties. First, it is morally wrong for humans to cause a species to go extinct. Second, it is morally wrong to introduce a species into an area in which it is not native. Unfortunately, human-induced climate change will cause species to go extinct unless we relocate those species to areas outside their native range. Thus, we are either causing species to go extinct or creating exotic species both of which are morally wrong. In this talk, I consider ways of dealing with the environmental dilemma."

  • "Move it or lose it? The ecological ethics of relocating species under climate change" by Ben Minteer and James Collins, Ecological Applications October 2010
    Lead author Ben Minteer is an environmental ethicist, and this paper is a strong and compelling piece of well-supported advocacy in favor of "managed relocation" (aka "assisted migration). The final paragraph reads: "If we value wild species and wish to bequeath a significant fraction of global biodiversity to future generations, radical strategies like managed relocation may well be our last best chance. Although risky, such bold efforts to preemptively move threatened species to new environments may offer the only hope to keep them from moving into museums and zoos—and haunting our ecological conscience." 4 pages in PDF.

  • "Future Human Intervention in Ecosystems and the Critical Role for Evolutionary Biology" by Jessica J. Hellmann and M.E. Pfrender, Conservation Biology December 2011
    EXCERPT: "We expect that considerable philosophical and conceptual change will occur within conservation biology over the next 25 years. If we acknowledge that the human population is growing and that the rapid pace of global change, including climate change, will continue, then we need to begin managing systems that are constantly changing — we can no longer look to the past for guidance on how an ecosystem is supposed to be."

    VIDEO ABOVE LEFT: Alejandro Camacho 2011: Redefining Nature through Assisted Migration (Natural Resources Law and Ethics Under Climate Change; 21 minutes)

    29:19 Begins • 31:21 Torreya example • 32:42 "Why do it, and why is this controversial? The existing literature focuses on whether assisted migration can be done — what I call, questions of scientific viability or legality. But I argue that the concerns with it, at their root, are deeply normative. They're really ethical. Assisted migration challenges deeply entrenched ideas about what the purposes are of natural resource law and natural resources management. But I argue that it is these principles and the legal framework that require rethinking." • 40:11 "We need to reinvent resource management to better reflect a dynamic world … "Natural resources management was not designed with climate change in mind." • 47:35 "I argue that climate change necessitates managing for the future." • 51:19 "I think assisted migration illustrates how resource management is not exclusively a scientific or legal inquiry."

    VIDEO ABOVE RIGHT: Alejandro Camacho 2012: Why Federal Climate Change Legislation Shouldn't Stop States from Innovating in Adaptation Efforts (29 minutes)

    00:01 Begins • 01:24 "My claim is that the law in the United States is not well suited to cultivate successful adaptation because it's not designed to foster learning." • 02:12 "U.S. law is not well suited to foster adaptation because it relies on (in fact, promotes) a very static view of nature and natural systems." • 04:45 "Climate change adaptation in particular is problematic because determining what are suitable adaptations is largely affected by the extent of mitigation … And we don't know that … So knowing what adaptation strategies to adopt, to restore certain mangroves, when we don't actually know if 50 to 100 years from now, whether all that work is wasted, is really problematic." • 06:21 "Scientists are really being challenged to reconsider long-held assumptions and long-held methodologies they've relied on. Regulators and managers are being asked to prepare for problems that they haven't ever faced before." • 06:54 "The most important strategies for effective adaptation, therefore, are those that help reduce uncertainty and that promote learning by managers and stakeholders in particular. [He cites 2 problems in the US] (1) Agencies are really slow to adapt to new information or changed circumstances. They aren't required to adjust their strategies over time … They don't gather information as to the effectiveness of their strategies; so the consequences are weak accountability. (2) Natural resources management in the U.S. is very fragmented, with at best weak coordination. It's not designed with climate change in mind. … It also hinders the capacity for learning between agencies." • 11:18 "Natural resources law in the United States is badly fitted for addressing the effects of climate change because of its goal, because of its objectives … grounded in a preservationist or restorationist baseline, a historical baseline . . . shielding nature from active human intervention … minimizing non-native and protecting native … Climate change reveals the limits of both of these versions of preservationism." • 15:23 "There is little ethical foundation for arresting the evolution of pre-existing ecosystems … Some of the reserves that have been set aside may actually become inhospitable to the very resources that they were created to protect." • 16:08 "Finally, climate change really pits these two different types of preservation — wildness preservation and historical preservation — against each other. Climate change makes it impossible to do both. You can't keep things the way they are and also leave them alone." • 22:02 "By not requiring agencies to monitor, to revisit, to adjust their decisions, to learn, this makes agencies less accountable to the public." • 25:15 "What climate change makes clear is that ecology and natural resource management should not be left solely to an expert: an economist, an ecologist. These are democratic decisions." • 29:00 Q&A starts

    See also print versions of these papers:

    2011: Alejandro Camacho's 2011, "A Learning Collaboratory: Improving Federal Climate Change Adaptation Planning"

    2010: "Why Federal Climate Change Legislation Shouldn't Stop States From Innovating in Adaptation Efforts"

    2013 VIDEO by Camacho: "The Law and Ethics of Assisted Migration" (48 min)

    Note: Serious students of assisted migration or, more broadly, the need for profound professional and public reconsideration of ecological norms in a time of rapid climate change will find it important to read the 86-page (freely downloadable) paper by Camacho, quotations from which follow:

  • "Assisted Migration: Redefining Nature and Natural Resource Law Under Climate Change", by Alejandro E. Camacho, 2010, in Yale Journal on Regulation, vol 27, pp 171-255.
    [86-pages in PDF freely downloadable] Argues for the necessity of assisted migration, owing to ongoing and projected climate change, and suggests changes in the U.S. ESA and regulatory policies for making this possible. Boldly addresses ethical concerns and the need for public discussion in the context of how assisted migration is a leading-edge issue that reveals the scope to which ecological preservation, restoration, and management will need to be thoroughly in light of the new awareness of significant climate change. Key quotations:

    Page 189: "Paradoxically, as detailed in the following subsections, under existing law it may often be more difficult for federal agencies to engage in assisted migration than it is for private parties."

    Page 243: "Assisted migration illustrates how climate change compels a reassessment of three key features of modern American natural resource governance. First, assisted migration demonstrates how climate change inevitably compels a reassessment away from baseline goals that seek to preserve or restore historical or existing conditions to a focus on maximizing desirable future conditions, although the particular formulation of such a goal for natural resource management is very much unresolved. Second, while making clear that biotic interactions will change considerably with or without direct human involvement, climate change necessarily reshapes the primary unit to target for management away from individual species or even assemblages of species toward ecological processes. Yet again, concretely steering resource management toward such a focus remains elusive. Third, the swiftness of climate change demonstrates that distinctions previously made in natural resource policy between native and exotic, or between natural and introduced, are overly simplistic and anchored in the flawed notion that the world is inert. Public resource management must explore new management standards for determining what ecological conditions are desirable or acceptable. Each of these necessitates substantial further public discussions to ascertain the future of public natural resource policy — and thus the prospects for assisted migration."

    page 244: "The conflict over assisted migration shows that the goal of preserving or restoring resources to a historic baseline that currently dominates natural resource policy will be increasingly difficult if not impossible to sustain. More than ever, modern anthropogenic climate change emphasizes the necessity of actively managing for the future. Yet the particular shape of such an objective is far from clear. As such, climate change necessitates extensive public discussions and ultimately legislative guidance regarding what is valuable and important to the public about natural resources such as endangered species and existing biotic communities."

    page 245: "Similarly, natural resource management must be transformed away from a primary focus on preserving or restoring historical biotic assemblages. With significant alterations in climatic conditions anticipated for many ecosystems, preservation and restoration goals will be increasingly unsustainable. Accordingly, statutes like the National Park Service Organic Act and Wilderness Act that primarily seek to preserve historical conditions will need to be reconceived away from a strict fidelity to the past toward a greater focus on promoting desirable future conditions in light of climatic changes."

    Page 251: "Lastly, assisted migration demonstrates the flaw in relying on absolute dichotomies such as native/exotic and natural/artificial as core features of managing biological systems under global climate change. Though such complete dualism has the advantage of simplicity, it is neither accurate nor helpful in deliberations over how to manage and choose among resources as ecological systems change with climatic conditions. Dedicating substantial resources to preserving and restoring a particular biological unit because it existed at one point in time in an ecosystem makes little sense if climatic conditions make the landscape inhospitable to that unit. Similarly, what is the ethical or scientific justification for prohibiting or removing any organism simply because it never existed in a particular location, especially if that organism is now well‐matched with the location due to changes in climatic conditions?"

    Page 253: "Though this Article provides a preliminary framework for assessing both when to allow and how to manage experimentation with assisted migration, it more importantly explains how climate change reveals a host of value questions that remain unexplored in natural resource law and policy. The resolution of these questions will shape not only determinations regarding the acceptability of assisted migration, but more broadly the future of natural resource management."

    Page 255: "In summary, a regulatory framework that fosters open and transparent access, debate, and deliberation can promote agency accountability to democratic representatives and the general public, and more informed public deliberation and action with regard to the management tradeoffs that must be made in devising goals and sandards for natural resource management. Though developing such institutions and processes will be far from easy, such a pursuit unquestionably should be the focus of natural resource law in a world of rapid climate change. The prior account of a pristine and untouched nature may be nearing its end. However, the opportunity to help foster biotic and human communities that truly integrate humanity's collective self-interest in resource conservation and duties of stewardship has really just begun."

    SEE ALSO: "Assisted Migration: A Viable Conservation Strategy to Preserve the Biodiversity of Threatened Island Nations?", by Jessica Wentz, 2011, Columbia Law School Working Paper.

  • "Reframing the Debate Over Assisted Colonization" by Joshua J. Lawler and Julian D. Olen, Frontiers in Ecology 24 March 2011
    EXCERPT: "In light of the difficulty in weighing the consequences of action versus inaction [re assisted colonization], we conclude that focusing the debate on this issue is counterproductive. In fact, we would argue that, given the magnitude of change that is likely to occur in many receiving ecosystems, there is little use in worrying about the effects of introducing one particular species. This is not to say that we should aban- don efforts to assess potential impacts to the receiving ecosystems. However, it does suggest that we consider the amount of change forecast for that ecosystem before conducting detailed experiments on a system that may not exist in the future."

  • "Hope in the Age of Man" by Emma Marris, Peter Kareiva, Joseph Mascaro, and Erle C. Ellis, New York Times 7 December 2011
    EXCERPT: "We can accept the reality of humanity's reshaping of the environment without giving up in despair. We can, and we should, consider actively moving species at risk of extinction from climate change. We can design ecosystems to maintain wildlife, filter water and sequester carbon. We can restore once magnificent ecosystems like Yellowstone and the Gulf of Mexico to new glories — but glories that still contain a heavy hand of man. We can fight sprawl and mindless development even as we cherish the exuberant nature that can increasingly be found in our own cities, from native gardens to green roofs. And we can do this even as we continue to fight for international agreements on limiting the greenhouses gases that are warming the planet. The Anthropocene does not represent the failure of environmentalism. It is the stage on which a new, more positive and forward-looking environmentalism can be built. This is the Earth we have created, and we have a duty, as a species, to protect it and manage it with love and intelligence. It is not ruined. It is beautiful still, and can be even more beautiful, if we work together and care for it."<

    EDITOR'S NOTE: For an opposing viewpoint, see "Conservation in the Anthropocene" by Tim Caro et al., Conservation Biology 2011.

  • VIDEO: Native Peoples Consider Assisted Migration of Plants (2012)

    Beginning at 10:18 into this United Nations video (featuring indigenous awareness of climate change around the world), mention is made of how native peoples in the USA are already looking a hundred or more miles south in order "to see what plants are similar to the plants that are thriving today, because those plants may no longer thrive on their reservation tomorrow. They are looking to see what relatives they may be able to move, to assist, from other places."

  • "Review of science-based assessments of species vulnerability: Contributions to decision-making for assisted migration" by Tannis Beardmore and Richard Winder, 2011, The Forestry Chronicle - The following tools (for assessing potential for assisted migration) are discussed in relation to their use in Canada: (1) the NatureServe Climate Change Vulnerability Index; (2) the System for Assessing Vulnerability of Species to Climate Change (SAVS); (3) the Forest Tree Genetic Risk Assessment; (4) the Index for Predicting Tree Species Vulnerability; (5) ecological standards developed for the assisted migration of Torreya taxifolia; and (6) the Seeds of Success Program.
    EXCERPT: "This example [Torreya Guardians] of assisted migration has raised the issue of authorization and oversight as the official federal recovery plan does not identify assisted migration as a conservation strategy for Florida Torreya. The momentum that this group has created resulted in the U.S. Fish and Wildlife Service considering whether assisted migration is an appropriate strategy for this species (U.S. Fish and Wildlife Service 2010). It is yet to be seen if official plans will include a more thorough assessment of the ecological impacts of assisted migration, or more extensive monitoring programs. Nonetheless, this is a very interesting example of how a grassroots organization can propel assisted migration into the forefront, causing a governmental agency to consider the use of this strategy."
  • "Assisted Migration: Adapting forest management to a changing climate", by Susan March Leech, Pedro Lara Almuedo, and Greg O'Neil, 2011, BC Journal of Ecosystems and Management
    In this paper, we discuss one forest management option — assisted migration — as a climate change adaptation strategy. We begin by providing context: an explanation of how rapidly our climate is predicted to change, how rapid climate change may impact ecosystems, and the body of evidence suggesting that it will be difficult for trees to keep up with predicted changes in climate over the coming decades. We then discuss assisted migration as one forest management option for dealing with climate change, describe perceived risks and benefits of different forms of assisted migration, and identify knowledge gaps, current research, and policy changes needed to implement assisted migration in British Columbia. Finally, we provide links to resources and additional information on this important topic.

  • "Why We Disagree about Assisted Migration: Ethical Implications of a Key Debate Regarding the Future of Canada's Forests" by I. Aubin et al., 2011, The Forestry Chronicle - "Although human-mediated movements are not a recent phenomenon, assisted migration has lately been the source of debate, in particular within conservation biology circles. In this paper, we outline the major perspectives that help define differing views on assisted migration and shed some light on the ethical roots of the debate in the context of Canadian forests."

  • OPINION: "Assisted colonization is not a viable conservation strategy", by Anthony Ricciardi and Daniel Simberloff, 2008, Trends in Ecology and Evolution Editor's note: This paper has often been cited as representative of arguments against assisted colonization.
    Strong argument against assisted migration in top ecological journal:

    EXCERPT: "Until we develop more accurate and general methods of predicting the impact of introduced species, cost-benefit analyses will be dangerously misleading. It is not yet possible to quantify the probability that a given species will go extinct because of climate change, or that a translocated species will harm one or more native species in a recipient community. To compare two such illusory numbers would lead to a false sense of scientific certainty. . . . Given this lack of predictive power, assisted colonization is tantamount to ecological roulette and should probably be rejected as a sound conservation strategy by the precautionary principle. Despite initial intentions to use such a strategy only as a 'tool of last resort,' there could be growing pressure to move species long before their populations begin to decline and their densities become low, because these conditions reduce the success of translocation [1]. We are concerned that increasing consideration of assisted colonization will promote unauthorized introductions of species by well-intentioned individuals, impede efforts to preserve habitat and, ultimately, create more conservation problems than it solves. In attempting to facilitate the persistence of threatened species, it is crucial to develop methods to increase the effectiveness of existing conservation measures (e.g. captive breeding, local population enhancement, habitat restoration) and, above all, mitigate human-induced stressors such as climate change; but there are many reasons to be skeptical about future conservation schemes that rely upon large-scale species translocation."

    EXCERPT PERTAINING TO TORREYA GUARDIANS: "... A recent position paper by the Ecological Society of Australia supports assisted colonization as a management response to climate change ( Other organizations could follow, driven by desperation in the face of anticipated species loss. Indeed, some scientists have claimed that rejecting assisted colonization will 'greatly increase the threat of climate-driven extinction' [4]. At least one private group has already taken matters into its own hands: the 'Torreya Guardians' (http:// are planting seeds and seedlings across the eastern USA to expand the range of an endangered conifer, Torreya taxifolia, whose modern distribution is confined to the Florida panhandle. These events signal the emergence among some conservationists of a new philosophy regarding species introductions that is at odds with the traditional objective of preservation...."

    2009 LETTER CRITIQUING Ricciardi and Simberloff (above): "Assisted colonization: Evaluating contrasting management actions (and values) in the face of uncertainty", by Martin A. Schlaepfer et al., 2009, Trends in Ecology and Evolution.
    EXCERPTS OF THE 3 CRITICISMS: "First, the probability of translocated organisms causing significant damage to native species might be overstated... Second, there is a need to weigh the risks of assisted colonization versus the risk of extinction using more traditional conservation practices.... We suspect that if a species were under imminent threat of extinction, could not migrate to suitable habitat, was unlikely to cause ecological harm and benefited from broad public support, few would argue against assisted colonization.... Third, risk assessments need to be evaluated and debated in a framework that recognizes that different stakeholders might place a premium on different outcomes. Even among conservation biologists, there appear to be divergent value systems that influence conservation targets and management tactics. Ricciardi and Simberloff appear to place a premium on protecting species in their native habitat, whereas proponents of assisted colonization are willing to translocate species to prevent their extinction even though in some cases this could result in adverse effects.... There is a need for a framework that integrates both biological information and socioeconomic data, and allows for debates regarding more subjective values surrounding species conservation. Hoegh-Guldberg et al. [6] proposed a relatively simple framework based on three categories: the need of a taxon (how imperiled is it?), technical feasibility (can it be translocated?) and suitability (do biological, social and economic benefits outweigh costs?)."
    2009 LETTER CRITIQUING Ricciardi and Simberloff (above): "Managed relocation: a nuanced evaluation is needed", by Dov F. Sax et al., 2009, Trends in Ecology and Evolution.
    EXCERPTS OF CRITIQUE: "Managed relocation (aka 'assisted colonization' and 'assisted migration' [1,2]) aims to save species from the effects of climate change by purposefully transporting them to areas where they have not previously occurred, but where they are expected to survive as temperatures increase. In a recent Opinion article in TREE [3], Ricciardi and Simberloff suggest that 'assisted colonization is tantamount to ecological roulette and should probably be rejected as a sound conservation strategy by the precautionary principle.' We disagree for three primary reasons. First, the precautionary principle is not a stand-alone reason to rule out managed relocation. It states that 'Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.' In the context of managed relocation, 'precaution' cuts both ways, as a motivation to avoid relocations that might cause unwanted harm and as a motivation to act before a species is driven extinct by climate change. Second, we know more about the impacts of species invasions than Ricciardi and Simberloff suggest, particularly with respect to species extinction. For instance, extinctions facilitated by exotic species occur primarily on islands (>90%) as opposed to continents [4]. Also, extinctions are generally caused by predation as opposed to competition; there are no documented cases to our knowledge where competition from exotic species has been the sole causal factor for the extinction of any native species [4].... Third, because extinctions are permanent and irreversible, using managed relocation to reduce extinctions at the cost of changing the composition and functioning of ecosystems is a tradeoff that some managers might be willing to make. This will be particularly true if most changes that result from relocations are small, and if those that are large are not necessarily detrimental. In considering these tradeoffs it is important to recognize that 'most invasions appear to have only minor impacts' [3] and that these impacts are not necessarily detrimental... Ultimately, the risk of species extinctions from climate change is too large to summarily discount managed relocation without first carefully evaluating its benefits and dangers in a nuanced way. Beginning this process now will better position us to make informed decisions in the years ahead, as threats of climate-mediated species extinctions become more common.
    2009 LETTER CRITIQUING Ricciardi and Simberloff (above): "Assisted migration: Part of an integrated conservation strategy", by Pati Vitt, Kayri Havens, and Ove Hoegh-Guldberg., 2009, Trends in Ecology and Evolution.
    EXCERPTS OF CRITIQUE: As part of a group of conservation biologists working to develop a framework for the appropriate use of assisted migration, we read with great interest the recent Opinion article in TREE by Ricciardi and Simberloff. Although we agree with several of their points, we believe that assisted migration could become an important part of integrated conservation strategies.... There is no 'one size fits all' strategy for assisted migration; each case requires independent consideration. We envisage assisted migration as having a role that mimics the natural dispersal of some species across landscapes, tracking the leading edge of their shifting bioclimatic envelopes, and it should be undertaken only if a species is not capable of natural migration, plastic response or adaptation in situ. Enhancing traditional conservation strategies will probably improve the rate of species survival in the absence of more extreme intervention and we recommend this as the first course of action.... Many species that are likely to be considered have already had populations restored within their native range or have been grown in botanic gardens and other cultivated settings both in and outside of their native range.... We also assert that, rather than paying 'little attention to the evolutionary context,' we embody a deep commitment to ensure that long-standing products of successful evolutionary lineages have a chance to persevere and continue their adaptive pathways. We recognize that assisted migration can be a 'slippery slope' and have also heard assertions that moving species around the globe represents their best chance for long-term survival. We adamantly reject this premise, and call for continued discussion within the conservation community to further define assisted migration and to distinguish it clearly from biological homogenization.
    2009 LETTER CRITIQUING Ricciardi and Simberloff (above): "The precautionary principle in managed relocation is misguided advice" by Mark W. Schwartz, Jessica J. Hellmann, and Jason S. McLachlan, Trends in Ecology and Evolution 2009
    EXCERPTS of CRITIQUE: "... The three of us have written and worked on the issue of managed relocation, and we differ in our concern about, and hope for, managed relocation as a conservation tool. One of us (M.W.S.) disagreed with Torreya Guardians (in 2005 and today) that the Florida torreya (Torreya taxifolia) should be translocated beyond its current range boundary. Despite this, the Torreya Guardians moved a federally listed endangered plant over 600 km without a single state or federal permit; and they were completely within their legal rights to do so. This action raises an important point: although managed relocation has potential risks and some ecologists might disagree with it in principle, it must be scientifically evaluated. Although it is possible that research will show that managed relocation should not be used, it should become an 'ecological bandwagon' because we do not want large-scale translocations to occur in a void of science policy. Rejecting strategies such as managed relocation based on the assertion that risk uncertainty is irreducible is equivalent to putting one's head in the sand.
          ...The precautionary principle has been historically useful in guiding conservation management, but global environmental change presents a different sort of problem. There are real risks of harm to biodiversity through inaction as well as action. The only way forward to confront unprecedented problems such as global anthropogenic climate change is careful risk analysis, including an honest evaluation of uncertainty and potential harm, along with broad public debate beyond the technical expertise of scientists and managers. We must engage in careful study of ethical, legal and biological issues surrounding the idea of managed relocation even if the ultimate conclusion is that it is the wrong approach to managing a difficult problem."
    NOTE: The September 2009 issue of Trends in Ecology and Evolution contains a total of 6 short papers or opinion pieces on the issue of assisted migration.

  • "Assisted Colonization Under the U.S. Endangered Species Act" by biologists Patrick D. Shirey and Gary A. Lamberti, in Conservation Letters, February 2010 3(1): 45-52 [full text in PDF online free access] ♦ Editor's note: This paper is an excellent summary of the ecological science, the law, the regulatory options, and the actions through 2009. It is clearly written from an objective position, neither pro nor con.
    "The paper represents a call to arms or a call to caution, depending on your perspective," says Gary Lamberti, the chair of the Department of Biological Sciences who is Shirey's advisor and co-author of the article. "When we're thinking about moving organisms around because of climate change or other environmental factors, we need to think about the legal framework that will enable or not enable us to do that. What Patrick did with his analysis was encourage policy makers and legal scholars to examine the statutes before we reach a crisis point." (quotation drawn from the author's online announcement of the paper). Here are several important legal conclusions made in the paper:
        "Current agency regulations impede alternative strategies such as assisted colonization for endangered animals, but do not impede assisted colonization of endangered plants." (p. 3) "On its surface, the statutory language of the ESA appears to provide the legal framework for allowing assisted colonization of endangered populations to new habitats primarily under Section 10(j), the experimental population provision" (p. 3) "In 1982 additions to the ESA, Congress sought to restrict the use of the experimental population provision as a means of removing protection from species and thus imposed procedural limits. Those limits, however, did not restrict the power of the agency to release species into suitable areas without considering historical distribution. The USFWS can authorize release outside the current range if 'release will further the conservation of such species' (citation). However, in promulgating regulations to implement the experimental population provisions, the USFWS added a geographic restriction in 1984 that prohibits an experimental population from being introduced outside the historic range, 'absent a finding. . . in the extreme case that the primary habitat of the species has been unsuitably and irreversibly altered or destroyed' (citation) (p. 5)
         "Perhaps the most successful case of assisted colonization of a plant listed under the ESA is the Virginia roundleaf birch (Betula uber). The first translocation of roundleaf birch occurred after the species was rediscovered in 1975 as a population of 41 trees (59 FR 59173). After the round-leaf birch was listed in 1978, the USFWS encouraged its distribution to conservation organizations and individuals (59 FR 59173). Despite protection of its habitat by agencies and landowners, the natural population of round-leaf birch declined to eight trees in 2003 ( However, because assisted colonization established 20 populations on U.S. Forest Service land, the USFWS reclassified roundleaf birch from endangered to threatened in 1994 (59 FR 59173)." (p. 6)
         "Regulatory restrictions placed on assisted colonization might be lesser obstacles to overcome than political and scientific resistance. Political opposition can include concern over costs of managing populations, resistance of landowners and local governments to introducing endangered species, and concern over species invasiveness. The threat of invasive species, in particular, raises legitimate scientific concern about assisted colonization." (p. 6) "Assisted colonization could be a viable management option to offset the human-caused and inseparable problems of habitat fragmentation and rapid climate change." (p. 7)

    EXCERPTS PERTAINING TO TORREYA TAXIFOLIA: "... The endangered Florida torreya (Torreya taxifolia) provides an example of a species moved without the application of Section 10(j). The conifer has been planted in the southern Appalachian Mountains by some members of the Torreya Guardians ( because habitat in the Florida panhandle no longer supports a viable population (McLachlan et al. 2007; Ricciardi & Simberloff 2009). The ESA does not restrict individuals from planting these trees outside of their native range if the seeds are acquired legally...."

    To see what is going on in Europe on this topic, see pp 42-43 of Convention on the Conservation of European Wildlife and Natural Habitats: Standing Committee Report of November 2009.

  • "Naturalness and Beyond: Protected Area Stewardship in an Era of Global Environmental Change", by David N. Cole and 15 other coauthors, 2008, in The George Wright Society Forum 25:36-56.
    Highly useful integrative paper geared for managers of natural lands that examines the need for new philosophical and practical perspectives on management of parks and wilderness areas today, especially given rapid climate change. "Assisted migration" is discussed in this report, but in the much wider context, thus making this paper a key reading for background perspective as well as precise philosophical and management options that supplement the criterion of "natural" with more precise understandings of "historical fidelity," biodiversity conservation," "resilience," and "ecological integrity."

  • "Don't Judge Species on Their Origins" comment by Mark Davis et al., Nature, 9 June 2011.
    Excerpt: "Today's management approaches must recognize that the natural systems of the past are changing forever thanks to drivers such as climate change, nitrogen eutrophication, increased urbanization and other land-use changes. It is time for scientists, land managers and policy-makers to ditch this preoccupation with the native v. non-native dichotomy and embrace more dynamic and pragmatic approaches to the conservation and management of species — approaches better suited to our fast-changing planet.

  • "Climate Change Turns Conservationists into Triage Doctors" CBC News (Canada). 30 November 2009
    Survey of a shift in conservationists attitudes: "The point is not to think outside the box, but to recognize that the box itself has moved and, in the 21st century, will continue to move more and more rapidly," University of Colorado ecologist Timothy Seastedt and his colleagues write in the journal Frontiers in Ecology and the Environment. Seastedt and others argue land managers must focus on ecosystem diversity to give plants and animals the best chance to adapt to the change scientists say is coming: The more diversified a system, the more resilient. Trying to return ecosystems to some historic or natural state is no longer possible, they say. "To be honest, the combination of climate and atmospheric chemistries we're experiencing now — you can't find any historical match," Seastedt says.


  • Interactive MAP of city-to-city climate shift projections (for urban ecologists and street tree planting decisions). Samples of maps:


       Note: The above MAPS and left are linked from:

    "New climate study matches cities to their future selves", which is a 2019 news report of this technical paper:

    "Contemporary climatic analogs for 540 North American urban areas in the late 21st century", Matthew C. Fitzpatrick and Robert R. Dunn, 2019, Nature Communications.

        • A September 2014 4-page article, "Have Tree, Will Travel" is a superb way to grasp the paleoecological foundation that undergirds projects for which poleward "assisted migration" on the continent of origin is becoming standard practice in this century of rapid climate change. The author, park planner Kevan Williams, weaves the science and policy viewpoints into three sequential narratives:
        (1) a futile recent Nature Conservancy project of attempting to "rewild" a native camellia, Franklinia alatamaha, southward to its "native" (actually, peak-glacial) habitat in southern Georgia from its cultivated (rescue) domain near Philadelphia.
        (2) the ongoing (and thus far successful) attempt by citizen naturalists to work around the Endangered Species Act and thus on their own initiative move a critically endangered Florida conifer, Torreya taxifolia (photo left), from its peak glacial refuge in northern Florida into the southern Appalachians and points farther north.
        (3) the disaster looming large for even common forest trees, as climate shifts rapidly, along with the role that massive projects of assisted migration, on the one hand, and urban forest landscaping, on the other, could play in helping species move north.

    "Cities as hot stepping stones for tree migration", by Qiyao Han et al., Urban Sustainability, 27 May 2021.

        ABSTRACT: Cities around the world are promoting tree-planting initiatives to mitigate climate change. The potential of such efforts to assist tree migration has often been overlooked. Due to the urban heat island effect, cities could provide suitable climates for the establishment of outlier populations, serving as propagule sources for poleward tree migration.

    EXCERPT: As a response to recent climate warming, cities such as Philadelphia, Chicago, and London (Ontario, Canada) have already begun planting more southerly tree species on urban parks, streets, as well as other municipal lands. However, the potential of urban tree planting to assist species migration in a wider landscape has often been overlooked. Due to the urban heat island effect, cities are experiencing a preview of future climates for nearby rural areas, potentially offering a climatic condition suitable for the persistence of outlier populations at higher latitudes than their native ranges. The outlier populations in cities could serve as propagule sources for species' poleward migration under climate change. Moreover, since trees can cool their environment, planting trees in cities can slow the rate of warming, which in turn allows them to grow for decades to reach reproductive maturity for further expansion. Here, we discuss the potential of urban tree plantings to assist the poleward migration of forest trees in temperate and boreal regions. Emphasis is placed on the unique climatic condition that cities could provide for the establishment, growth, and expansion of outlier populations.
        ... The stress induced by rapid climate warming will be exacerbated by the negative effect of extreme weather events (e.g., heat waves, drought, floods, and storms), which constrain the establishment and spread of tree species. The consequent decoupling between climate shifts and species migrations may result in species extinction, as happened to a species of spruce, Picea critchfieldii, in eastern North America after the Last Glacial Maximum.
         Despite the pessimistic predictions, empirical studies of postglacial recolonization indicate that trees in boreal and temperate regions may not necessarily lag behind climate change, as species migration can be facilitated by the persistence of outlier populations in advance of their main ranges. Rapid range shifts of boreal and temperate trees occurred following the retreat of ice sheets after the last glacial period. Molecular evidence suggests that such range shifts were achieved by local dispersal from small, isolated populations occupying high-latitude microrefugia, where climates were favourable for their persistence outside of main ranges during the glacial period. A well-documented example is ice-free refugia in northern Scandinavia, which supported the survival and expansion of conifer trees after the Last Glacial Maximum. Recent models have also highlighted the favourable effects of outlier populations on poleward range shifts. The role of outlier populations in the past may have an analogy under future climate change, as outlier populations not only can occur naturally as relicts of past climates but also could result from anthropogenic planting. Even a small number of trees planted far beyond their native range limit can be sufficient to establish naturalized populations.
         URBAN HEAT ISLANDS AS STEPPING STONES. Cities are already ahead of their surroundings in terms of climate warming, therefore potentially offering suitable climate conditions for the establishment of outlier populations (Fig. 1). Urban areas tend to have higher temperatures than their surrounding rural areas as if a warmer city air lies in a "sea" of cooler rural air. This phenomenon has been commonly observed and investigated around the world, known as the urban heat island effect. Generally, the urban heat island effect is an "inadvertent" modification of local climates during urbanization.... In Baltimore, for example, urban-rural differences in air temperature are similar to projected climate changes over the next 50-100 years.... Planting outlier populations in urban heat islands is expected to provide a substantial head start on poleward range shifts.... It is, therefore, possible to shorten or even eliminate migration lags in tree species by planting outlier populations in cities.... An investigation of 357 European plant species showed that 73% of them have been moved into nurseries and gardens hundreds or even thousands of kilometres north of their natural range limits. In the eastern United States, southern species planted in northern urban areas as ornamental plants are expected to speed the process of tree migration to a rate of 1 km per year.... The process of range expansion can be supported by urban green spaces, such as private gardens, agricultural islands, roadside hedges, and copses. These man-made landscapes could work as a series of habitat islands that provide stop- over points, food, and shelters for the movement of seed dispersal agents (such as crows, jays, and nutcrackers) from urban to rural areas.
         USING CITIES AS STEPPING STONES: Establishing outlier populations in cities can be regarded as a form of assisted migration (also called managed relocation or assisted colonization), which refers to the intentional translocation of species and populations outside their historic ranges to facilitate their range shifts under climate change. Here, cities are perceived as 'hot' stepping stones for poleward migration, whilst species' future distributions are viewed as moving targets, which can be achieved by successively establishing outlier populations in cities along latitudinal gradients (Fig. 2). The 'climate analogues' approach developed by CCAFS50 can help identify cities that have similar climatic conditions with those of species' native ranges at lower latitudes. Besides, the outlier populations established in cities can provide additional nursery capacity for assisted migration in local and regional spheres. For example, public parks and botanic gardens could serve as nurseries to test and accommodate translocated seeds and seedlings, providing a future supply of trees for efforts of assisted migration in nearby rural areas. Such efforts also avoid some problems associated with planting species outside their native ranges: not only because cities could provide them with extensive horticultural expertise, regular care, and record-keeping, but also because cities could offer real-world laboratories for ecologists, foresters, and managers to monitor and minimize the invasiveness of translocated species in their new environments, as well as their potential for creating pest problems, before the implementation of large-scale tree plantings..
         It should be noted urban tree plantings that aim to assist tree migration will be able to reduce losses of ecosystem services in urban environments due to climate change. Trees are a vital part of urban ecosystems. Maintaining and enhancing the long-term health of trees is essential for urban forests so that they can continue to provide ecosystem services, such as climate regulation, air purification, and carbon sequestration. The rate of recent climate change has exceeded the capacity of some native trees in urban environments to adapt, leading to increased mortality and susceptibility to fungal disease, insects, and other pathogens. One example is the native trees in the city of Bellevue, Washington, including western red cedar, western hemlock, and Douglas fir, which are experiencing a higher mortality rate due to drought stress. Efforts of assisted migration in urban areas can help establish new and better-adapted urban forests that support the sustainability of urban ecosystems.... Gardeners need to think beyond beauty when selecting species and more on the potential of horticulture to serve as a route of assisted migration.

  • "Climate change to Philly trees: It's not 1910 anymore" (news article) by Carolyn Beeler, 23 January 2015. Surveys Philadelphia and Chicago urban trees and parks managers who have already begun planting more southerly tree species on municipal lands. Joan Blaustein, head of urban forestry and ecosystem management at the Philadelphia Parks Department, is quoted: "We need to anticipate what the conditions are going to be 100 years from now, rather than trying to restore to 100 years ago." Beeler writes, "In the fall, the city will plant non-native trees suited to warmer climates, including the Southern chestnut oak and bald cypress, and plant some species native to Pennsylvania that are currently at the northern end of their range, such as the Southern red oak and red mulberry. . . In five years, Blaustein hopes the early results of her experimental test plots will give her an idea of which new trees to plant city-wide." 2019 NEWS UPDATE: "Some of Pennsylvania�s iconic tree species might not survive climate change", by Frank Kummer, Philadelphia Inquirer.

  • "Vancouver trees might not survive climate change", 29 February 2016, by Michael Mui, in 24 Hours Vancouver. Key quote: "[Bill] Stephen said that about 40 years from now, it's predicted the Metro Vancouver's climate would be much like northern California today." Editor's note: That news article is based on the newly released lengthy report: "Urban Forest Climate Adaptation Framework for Metro Vancouver: Tree Species Selection, Planting, and Management", February 2016, submitted to Metro Vancouver (Canada), by Diamond Head Consulting. Note: This is a long pdf. Advance to page 27, where this report begins as an attachment. See excerpts below.

    EXCERPTS: As a regional government, Metro Vancouver has an interest in increasing the resilience of the urban forest to climate change and maximizing the benefits from urban forests in the region. This project was initiated in response to concern that the region's existing urban forest may not be well suited to the changing climate and, if so, the need for practical guidance on how to adapt the urban forest. Healthy urban forests mitigate climate change and can help people and organisms adapt to the changing climate, playing a large role the region's ongoing livability. (p. 31) . . . Trees are a keystone structure of urban ecosystems [6]. Maintaining and enhancing the health and resilience of trees is essential for urban forests to continue producing beneficial services. (p. 32) . . . Tree populations in western North America [already] lag behind their optimal climate niche by approximately 130 km in latitude or 60 m in elevation (p. 49). . . The annual average temperature in Metro Vancouver is projected to warm by about 3�C over the next 40 years (p. 50). . . The longer growing season expected under climate change may expand the diversity of trees that can be planted in Metro Vancouver (p. 53). . . Fewer frosts and milder winters will enable some new tree species to successfully overwinter in Metro Vancouver. It is expected that the dominant extreme minimum temperature zones for the region will shift from USDA Hardiness Zone 7-8, to Zones 8-9. Longer growing seasons may also increase the growth and productivity of some tree species given adequate soil moisture and nutrient availability. However, responses are likely to be species specific due to differing developmental cues related to temperature and photoperiod. Regional evidence for how tree species will respond to a lengthened growing season is limited. Models generally agree that there will be fewer frost days, milder winters and a longer growing season (p. 57). . . Metro Vancouver has developed a "Design Guidebook" to assist people in designing tree plantings that maximize the climate adaptation benefits of urban forests. The guidebook provides the context for selecting an appropriate species across a wide range of tree planting opportunities (p. 60). The pace of climate change may exceed the capacity of native trees to adapt and there may be justification to influence the direction and timing of adaptation through assisted migration of better adapted tree species and seed sources. For native trees, seed provenance choice will be an important consideration because trees are already lagging behind their optimal climate niche. Further research is required to understand how assisted migration may be of relevance to managing native forests within an urban forestry context, and within the context of biotic nativeness in our region (p. 61). Metro Vancouver's heat days are projected to change from an average of 2 days per year to approximately 28 days per year in the 2080s. This represents a change from an average of heat zone 2 to an average of zone 4 or zone 5 at the upper range of variability (p.62).

  • Garden Plants Get a Head Start on Climate Change, by Sebastiann Van der Veken et al., May 2008, in Frontiers in Ecology and the Environmnent.
    ABSTRACT: Conservation biologists are concerned that climate change will cause widespread extinctions because limited capacity for migration could compromise species' ability to adjust to geographic shifts in habitat condition. However, commercial plant nurseries may provide a head start for northward range shifts among some plant species. To investigate this possibility, we compared the natural ranges of 357 native European plant species with their commercial ranges, based on 246 plant nurseries throughout Europe. In 73% of native species, commercial northern range limits exceeded natural northern range limits, with a mean difference of approx. 1,000 km. With migration rates of 0.1 to 5 km per year required for geographic ranges to track climate change over the next century, we expect nurseries and gardens to provide a substantial head start on such migration for many native plants. While conservation biologists actively debate whether we should intentionally provide "assisted migration", it is clear that we have already done so for a large number of species.

    MORE EXTRACTS: Here, we investigate the potential for commercial nurseries to provide a head start for northward range shifts of native European plant species in the face of ongoing climate change, and address the question: to what degree have we already inadvertently assisted plant migration.... l. 2006). Thus, extending range limits through horticulture, as demonstrated here, may have a profound impact on the northward movement of the range boundary within which plants grow without direct human assistance. In some cases, this may allow extinction to be averted.... Of the 534 ornamental species sold in Britain during the 19th century and examined by Dehnen-Schmutz et al. (2007), 27% were subsequently found growing outside of cultivation, and 30% of these had established populations, clearly demonstrating the potential for horticultural plants to spread into non-cultivated habitats (see Sullivan et al.2005).

  • California Redwoods and Sequoias Thrive in Pacific NW Cities - multi-part VIDEO series by Connie Barlow on youtube, 2017.
       From Portland OR to Seattle WA and northward, Coast Redwoods and Giant Sequoias planted a century or more ago (and still being planted) as urban landscaping demonstrate that the climate hundreds of miles northward of their historically native range is already adequately warm for these California endemics to thrive. The first episode in this video series documents a gone-wild area in the urban landscape north of Seattle where an old redwood tree is now surrounded by offspring of various ages — all with no human assistance. The species has therefore "naturalized" but is not otherwise invasive. Other episodes document the two species thriving as street trees and in urban parks.

  • Tennessee Trees Moved to London Ontario? (news article) by Spencer Van Dyk, 23 December 2015, in The London Free Press (Canada), title: "London's urban foresters are laying the groundwork to test tree species now found in warmer climates". EXCERPTS:
       If rising global temperatures and Mother Nature have their way, pecan trees could be growing in London in 100 years or so. If urban foresters at city hall have their way, some trees indigenous to Tennessee, more than 1,000 kilometres to the south, will be rooted here a lot sooner than that. They want extra money in the 2016 budget from council for a project that would diversify the kinds of trees that grow in London, bringing in ones more suited to a warmer climate. It's a process called assisted migration.
         "Species that can survive in Tennessee today might be able to survive our future climate," said Sara Rowland, an urban forestry planner for the city. The first step would be more testing in 2016 by planting seeds in test plots from species that don't grow here now.
         . . . Assisted migration accomplishes what would otherwise take generations. If the city imports trees from 1,000 km south, London's trees could be moved north to somewhere like Thunder Bay, Rowland said.

    2019 UPDATE ASSISTED MIGRATION IN ONTARIO: " Trees for a changing climate: Program introduces southern trees to Ontario", by Kathleen Saylors, 24 September 2019, Woodstock Sentinel Review.

    EXCERPTS: The Upper Thames River Conservation Authority and the Forest Gene Conservation Association, an organization that collects and protects tree seeds for the future, are launching a new test project in Oxford. The premise is simple: it takes tree seedlings from warmer climates and plants them side by side with local trees of the same species.... Officially, it's called assisted tree migration — something that happens naturally but, in this case, isn't happening fast enough to help trees survive climate change. "We are picking seeds from places already adapted to the 2050 (climate)," said Spearing. "In these trees, the genetics already know hot, dry summers. We have to artificially assist and move them or we risk not having good stock for the future." To test the theory in Ingersoll, the groups are using bur oak trees, which are found locally, as well as in Tennessee and Pennsylvania, two warmer climates where the trees are already accustomed to a short growing season and hot, dry summers.

  • This is a job for garden superheroes! (news article) by Tom Atwell, 7 October 2018, in Maine Gardener section of Press Herald. Tagline: Gardeners who sign on for assisted migration could save plant species from extinction.
    EXCERPTS: Gardeners who push the zones — planting U.S.-native plants that should be too tender to survive where the gardeners live — may play a key role in saving plant species from extinction. With climate change, many plants are likely to need saving.
         We are in the midst of the sixth mass extinction in the history of the Earth, Jesse Bellemare, an associate professor of biological sciences at Smith College in Northampton, Massachusetts, reminded the audience in a lecture at Coastal Maine Botanical Gardens late last month . Previous mass extinctions were caused by such things as asteroids and volcanoes. But humans are to blame for this one. Editor's note: Do an internal "Find" on this webpage to locate the many instances in which Bellemare is published and quoted.
         ... The warming of the earth is moving horticultural zones — the places where specific plants can grow and survive — northward (on this side of the Equator) by about 400 meters a year, Bellemare said, the equivalent of a quarter of a mile. The U.S. Department of Agriculture first issued Plant Hardiness Zone maps in 1960. In 2015, the USDA adjusted its 1990 Plant Hardiness Zone map, but Bellemare's research leads me to believe it may need more adjusting.
         Plants can't simply follow that quarter-mile-a-year movement, Bellemare said. Take plants like trillium and bloodroot — seeds are transported by ants. The ants move them only a few feet per year — not even close to keeping up.
         Geological history provides no hope, either. After the last glaciers killed all plants in the northeastern United States, the region was again populated by plants. But it took centuries — they moved north at a rate of about six meters a year, Bellemare said. That translates to 600 meters a century, nowhere near the 400 meters a year that climate change is moving the zones.
         Consider the white pine — the official state tree of Maine. If winds or birds moved the seeds 400 meters in a year — possible but not likely — it still would take many years for the white pine seedling that sprouted to get mature enough to produce seeds of its own. So the movement of white pines would still be much less than 400 meters annually.
         So, how can gardeners help plants keep apace? By participating in something called assisted migration. Some botanists are recommending transplanting plant species to save them. The poster child for this practice is Torreya taxifolia, or Florida nutmeg, a tree that is native to the Florida panhandle and is now threatened there. Some people want to move it north to save it. Others oppose the idea because it could result in introducing an invasive species to an area where the plant doesn't naturally exist.
         The debate is continuing — but the debate might not matter. "Might horticulture already be serving as a route of unplanned assisted migration?" Bellemare asked. And being a research botanist, he and some associates conducted a study to find out. They studied the umbrella magnolia, Magnolia tripetala; its native range is in the Gulf Coast, spreading up to southern Pennsylvania.
         The tree has been in the horticultural trade since the 1700s. In fact, it was offered for sale by John and William Bartram — nurserymen whose illustrious clients included Benjamin Franklin, George Washington and Thomas Jefferson. In 1822, a catalog from a company in Long Island, New York, shows the magnolia selling for 50 cents a tree, and it came to New England in mid- 1800s — including to the home of poet Emily Dickinson in Amherst, Massachusetts, where some large specimens still grow.
         ... It might seem surprising that such a tree could survive and grow beautifully in western Massachusetts, a long way from its native range and where temperatures can get pretty cold. It can survive, but it can't reproduce unless the conditions are right. And the conditions are becoming right.
         Bellemare and his assistants searched areas around where the umbrella magnolia had been planted at homes and found several stands of umbrella magnolia with healthy seedlings and a few trees mature enough to produce seeds themselves. Taking cores from the escaped trees, the researchers found that most of the relatively old ones date from 1989 to 1993, at which point the climate had grown warm enough for seeds from the trees in people's yards to reproduce naturally.
         Bellemare then went to the southern edge of the umbrella magnolia�s original native range, and found that the tree is struggling. Big plants were ailing. Many small plants were sprouting from the dying trees� roots — much as happens with chestnuts in the Northeast — which will produce a tree, sure, but he found no new trees sprouting from seed, an indication the species was neither thriving nor expanding.
         So the entire viable habitat for the tree is moving north. The question now is whether accidental assisted migration is a good thing. "We have to ask, 'Is this plant invasive or weedy, or is it something like a climate refugee?'" Bellemare said.
         Assisted migration has its potential downsides. The plants that are likely to benefit are the attractive ones, with big flowers and showy foliage, because that is what people often look for when they buy for their home gardens. The less attractive plants — which still may be critical to support wildlife — could be left behind, resulting in an overall low diversity of plants.
         According to Bellemare, the possibility of these climate refugee plants becoming invasive is low. He cited the New England Wildflower Society's survey of plants in New England in 2011, which found 376 U.S. (but not New England) natives that are in our fields and forests. Fewer than 10 of these are listed in the Invasive Plant Atlas of New England as invasive or potentially invasive. Plants from other continents have a much higher chance of becoming invasive than those from North America, Bellemare said.
         All of this information means gardeners have more than ever to think about when they choose plants. We�ve been thinking about how the plant will look and if it fits our garden conditions for as long as we've gardened. We�ve been thinking about how plants we choose will improve the local ecosystem for a few years. On top of these, we now have to decide if we want to take part in assisted migration.



    The tools and approaches developed in the urban project are designed to be applied to any urban, suburban, or other developed area in the Midwest and Northeast. The Chicago Wilderness region was chosen as a pilot area to test these ideas, with the intention of applying lessons learned to other metropolitan regions and municipalities in the future.

       EXCERPTS: Over the past century, the Chicago Wilderness region has warmed by about 1 degree F on average and has had a significant increase in precipitation, especially during the summer (3-inch increase). Mean annual temperature is projected to increase by 2.3 to 8.2 degrees F by the end of the 21st century, with temperature increases across all seasons. Rises in temperature may lead to a shift of one to two hardiness zones and two to four heat zones. Species distribution modeling for native species suggests that suitable habitat may decrease for 11 primarily northern species, and increase or become newly suitable for 40 species.
        Greater financial investments may be required in the short term to maintain the urban forest so it can continue to provide benefits to the community, such as clean air, reduced heat island effects, and stormwater management, in the long term. At the same time, confronting the challenge of climate change also presents opportunities for managers and other decisionmakers to protect their investments by planning ahead, building resilient landscapes, expanding their volunteer base...
        Of the 134 tree species modeled in DISTRIB, 70 were of interest to the Chicago Wilderness region because they are currently present or expected to gain suitable habitat in the area. Projected changes in potential suitable habitat for these 70 species are compared to present values for the years 2070 through 2099 in Table 3. Species were categorized based on whether the results from the two climate-emissions scenarios projected an increase, decrease, or no change in suitable habitat compared to current conditions, or if the model results were mixed. Further, some tree species that are currently not present in the assessment area were identified as having potential suitable habitat in the future under one or both scenarios [see table left].
        Projected changes in habitat suitability for native species in this study do not always align with those published in the Tree Atlas (discussed earlier), which could be for a number of reasons. First, these modeling efforts rely on different downscaled climate datasets as inputs to the models. Second, they use different modeling approaches with different underlying model structure and climate parameters. Third, the tree data are from a different source for each model: Tree Atlas relies on FIA data from natural environments, whereas this study relied on survey data from cultivated settings. This discrepancy does not mean that either or both of these model projections are wrong, but rather that modeling habitat suitability in urban environments is complex and may depend on site-specific situations and the degree to which a site is developed.

    EXCERPTS cont: We developed modifying factor scores for all 120 species listed as occurring in the Chicago area according to the recent Regional Tree Census (Nowak et al. 2013). In addition, we included other species that are being considered on planting lists for the City of Chicago and the Chicago Region Trees Initiative, bringing the total number of species evaluated to 179. For species present only in a cultivated setting, we generated only one score. Native species, even if not currently used in cultivated settings, were given scores for both planted and naturally occurring settings. Scores were then converted to categories of high, medium, and low adaptive capacity (Tables 6-11). See Appendix 6 for specific modifying factor scores and subscores for each species and a description of the two numerical scoring systems.
        EXOTIC INVASIVES: A modeling study suggests that warmer temperatures could aid the spread of kudzu across Illinois by the end of the century (Bradley et al. 2010). Although the risk to the Chicago area was projected to be low, the urban heat island effect was not accounted for in this study. Another study examined the potential future distribution of kudzu for the year 2035 using trends in observed climate data; results also suggest that kudzu will move northward but will still be south of Chicago (Jarnevich and Stohlgren 2009). Chinese and European privet are invasive flowering shrubs that crowd out native species and form dense thickets. Model projections suggest that the risk of privet invasion into the Chicago Wilderness region may be similar to that of kudzu by the end of the century (Bradley et al. 2010).
        PATHOGENS: Milder winters could be beneficial for the emerald ash borer, which is already causing extensive damage to ash trees across the area (Venette and Abrahamson 2010). Drought stress, which could occur later in the growing season, may make trees susceptible to attacks by boring insects such as bronze birch borer and two-lined chestnut borer and to diseases such as Botryosphaeria canker. Oak wilt, a high-mortality disease of oaks in the region, benefits from cool, moist conditions for transmission and hot, dry conditions for disease progression. Thus, wetter springs followed by hot dry summers could make oak wilt a larger problem in the Chicago Wilderness region in the coming decades. A changing climate is also likely to increase the susceptibility of tree species to pests and diseases that are not currently a problem in the Chicago Wilderness region. High spring precipitation has been associated with severe outbreaks of bur oak blight in Iowa, which could put Chicago-area bur oaks at risk if springs become wetter (Harrington et al. 2012). Milder winter temperatures could allow southern pine beetle to migrate northward (Ungerer et al. 1999). Beech bark disease and thousand cankers disease may benefit from warmer winter temperatures (Kasson and Livingston 2012, Luna et al. 2013). However, the risk for some diseases may be reduced under a changing climate. Climate conditions are currently only marginal for sudden oak death in the Chicago Wilderness region (Kluza et al. 2007, Venette and Cohen 2006), and models suggest that conditions may become less suitable in the future (Venette 2009). Additional pests and diseases may invade for reasons other than climate change. The northern distribution of Asian longhorned beetle does not appear to be driven by winter temperatures, and this pest has already been found in Chicago (Antipin and Dilley 2004, Roden et al. 2009).

       UC Research Finds That Inland California Trees Will Not Persist In 2099 Climate, Sierra Sun Times, 4 August 2018.

    EXCERPTS: Many common street trees now growing in the interior of California are unlikely to persist in the warmer climate expected in 2099, according to research published in the July 2018 issue of the journal Urban Forestry & Urban Greening. "Urban foresters in inland cities of California should begin reconsidering their palettes of common street trees to prepare for warmer conditions expected in 2099 due to climate change," said the study's co-author, Igor Lacan.
         "Our research shows that some trees now lining the streets of cities like Fresno, Stockton and Ukiah are likely to perform poorly in 2099," Lacan said. "Those cities need to look at the conditions — and trees — now found in El Centro, Barstow and Fresno respectively." To reach these conclusions, Lacan and co-author, professor Joe McBride of UC Berkeley, used space-for-time substitution. They compared the most common street tree species in cities representing each of the 16 California climate zones with trees in cities that currently have climates that approximate the expected warmer conditions in the 16 cities 80 years from now.
         Lacan said he and McBride were surprised to find that coastal cities and their warm equivalents contain most of the same common urban tree species, while the warm equivalents of inland cities seemed to lack most and, in some cases, all of the common trees there today. "It's really a sharp distinction," Lacan said. "Perhaps they were lucky, but coastal cities are better positioned for the climate of 2099 than the inland cities."

  • "Species Migration Shaping Ecosystems of the Future" by Ruby Russell, 14 October 2014, Deutsche Welle
    KEY POINT: Those of us in the northern hemisphere may need to assist the poleward migration of today's even common species, but the biggest problem resides in the Southern Hemisphere — where terrestrial species may ultimately run out of southern latitude lands, owing to the shape and locations of the continents.

    CONCLUDING EXCERPT: "Looking at all life-forms, it is trees that move the slowest. The majority of trees cannot keep pace with climate change," Torreya Guardians' founder Connie Barlow says, adding that the Florida torreya's seeds are too large to be carried by the wind or most animals. Assisted migration is controversial, but Barlow and others argue that on a continental landmass like Europe or North America, terrestrial species have shifted back and forth with climatic change over the millennia, so that what seem like 'new' species combinations have actually existed in the past.
         What is unprecedented is the rate at which climate change is now happening. Chris Thomas says this means defending current species combinations may not always be the best approach. "If all our biological communities are going to change anyway, why should we not think about including within those biological communities — even if it requires us to intervene — some of those species which are truly endangered?" asks Thomas. He says some may not think this is very natural. But, then neither is current climate change, he points out.

  • "Assessing the potential for urban trees to facilitate forest tree migration in the eastern United States" by C.W. Woodall et al., 2010, Forestry Ecology and Management - helpful charts showing large urban areas of northeastern USA that have tree species in plentiful plantings north of their native range (e.g., Sweet Gum (Liquidambar) planted in New York City is 2 degrees latitude farther north; Southern Live Oak and Water Oak planted in Boston are 8 degrees and 5 degrees, respectively, farther north). Caveat: Ability of those individuals to actively move seed into surrounding wild forests is low; thus suburban plantings and outward plantings by landscapers will be more important to facilitate assisted migration in pace with climate change.

  • "As World Warms, How Do We Decide When a Plant is Native?" by Janet Marinelli, 2016, in Yale Environment 360. This excellent journalistic piece puts a recent botanical paper in the wider context of climate change and assisted migration. Lead author Jesse Bellemare is quoted in the article; his original paper (which features the USA understory tree Umbrella Magnolia), "Horticultural escape and naturalization of Magnolia tripetala in western Massachusetts: Biogeographic context and possible relationship to recent climate change", is excerpted in the Magnolia section of this webpage. Marinelli's article highlights the role of horticultural gardens in (inadvertently) facilitating long-distance assisted migration of otherwise slow-to-migrate native plant species. Her final paragraph:
    "While scientists grapple with the implications of escaped magnolias, there is poetic justice that a plant from the Dickinson homestead has sparked the discussion. Although the view of enduring wilderness championed by Thoreau and John Muir came to dominate conservation thinking, Emily Dickinson, who perceived the beauty and destructive capacity of nature all around her, may be the more appropriate literary icon for an age of climate disruption."


  • How the Parks of Tomorrow Will Be Different, by Michelle Nijhuis, National Geographic Magazine, December 2016

    EXCERPTS: Tagline: America's most special places will always be beautiful, but a warming climate forces us to accept that they can't be frozen in time.
         ... When Nate Stephenson was six years old, his parents fitted him with boots and a hand-built wooden pack frame and took him backpacking in Kings Canyon National Park. For most of the 53 years since, Stephenson has been hiking the ancient forests of the Sierra Nevada....Now he's a research ecologist there, studying how the park's forests are changing. While park managers are often consumed by immediate crises, researchers like Stephenson have the flexibility — and the responsibility — to contemplate the more distant future. In the 1990s this long view became deeply disturbing to him. He had always assumed that the sequoia and foxtail pine stands surrounding him would last far longer than he would, but when he considered the possible effects of rising temperatures and extended drought, he wasn't so sure — he could see the "vignette of primitive America" dissolving into an inaccessible past. The realization threw him into a funk that lasted years.
         At Sequoia, Stephenson wants park managers to consider planting sequoia seedlings in a higher, cooler part of the park — to see how the seedlings fare, and also how the public would respond to experimenting with the icons. "We have to start trying things," he says.
         "I was a firm believer in the mission of the Park Service," Stephenson remembers, "and suddenly I saw that the mission we had was not going to be the same as the mission of the future. We could no longer use the past as a target for restoration"; we were entering an era where that was not only impossible, but might even be undesirable."
         Stephenson began what he calls a "road show," giving presentations to Park Service colleagues about the need for a new mission. Somewhat mischievously, he proposed a thought experiment: What if Sequoia National Park became too hot and dry for its eponymous trees? Should park managers, who are supposed to leave wild nature alone, irrigate sequoias to save them? Should they start planting sequoia seedlings in cooler, wetter climes, even outside park boundaries? Should they do both — or neither?
         ... At Sequoia National Park, Stephenson wants park managers to consider planting sequoia seedlings in a higher, cooler part of the park — to see how the seedlings fare, and also how the public would respond to experimenting with the icons. "We have to start trying things," he says.

  • The broad footprint of climate change from genes to biomes to people, by Brett R. Scheffers, Science, 11 November 2016.
    EDITOR'S NOTE: Science is a top science journal in the world. In the excerpts below, it is now indisputable that climate is changing already far too fast for many species to keep pace with, absent human-assisted migration.
         EXCERPTS: In addition to reducing greenhouse gases, climate action and policy must therefore focus equally on strategies that safeguard biodiversity and ecosystems... Atmospheric concentrations of greenhouse gases from burning fossil fuels and de-forestation are approaching levels that have not been detected in the past 20 million years... We present examples of case studies of observed impacts across terrestrial and aquatic biomes and find evidence that climate change is now affecting most biological and ecological processes on Earth — spanning genetics, organismal physiology and life-history, population distributions and dynamics, community structure, and ecosystem functioning... Changes in species ranges have altered or created new hybridization zones across the planet. For example, in North America, hybrid zones between black-capped (Poecile atricapillus) and Carolina chickadees (P. carolinensis) are shifting in response to warmer winter temperatures, and because the southern flying squirrel (Glaucomys volans) has expanded its range northward in eastern North America, it is now hybridizing with the northern flying squirrel (G. sabrinus)... One of the most rapid responses observed for marine, freshwater, and terrestrial species is a shift in their distributions to track optimal habitat conditions. Across land and aquatic ecosystems, species have expanded their leading (cold limit) edge by 19.7 km per decade, with marine species expanding by 72 km per decade compared with 6 km per decade in terrestrial species... Several native insect species from North America, with no prior records of severe infestation, have recently emerged as severe pathogens of forest resources because of changes in population dynamics. These include the Aspen leaf miner (Phyllocnistis populiella), the leafblotch miner (Micrurapteryx salicifoliella), and the Janet's looper (Nepytia janetae), which have decimated millions of hectares of aspen, willows, and spruce-fir forests since the early 1990s. Known pests such as mountain and southern pine beetles (Dendroctonus frontalis and D. ponderosae, respectively) and spruce beetles (D. rufipennis) have recently expanded their distribution and infestation intensity on commercially important pine and spruce trees. These outbreaks may increase in the future because hundreds of plant pest and pathogen species have shifted their distributions 2 to 3.5 km year poleward since the 1960s.

  • Tree die-offs soaring, bringing fire danger and exacerbating water problems, news report, Orange County Register, 19 November 2016.
    EDITOR'S NOTE: Although this article makes no mention of assisted migration, the shocking escalation in tree deaths in California calls out for the need to normalize assisted migration as a first-order climate adaptation approach — now.

    EXCERPTS: Agriculture Secretary Tom Vilsack and Forest Service officials are seriously hampered not only by short-term budgets passed by Congress but also a broken budget for the Forest Service that sees an increasing amount of resources going to firefighting while less is invested in restoration and forest health, Vilsack said in a statement. Most of the 102 million dead trees are within 10 counties in the southern and central Sierra Nevada region. The Forest Service also identified increasing tree mortality in the northern part of the state, including Siskiyou, Modoc, Plumas and Lassen counties. This year, California had a record-setting wildfire season, with the Blue Cut fire alone scorching over 30,000 acres, mostly in the San Bernardino National Forest, and triggering the evacuation of 80,000 people, the statement said. As the state enters the sixth year of drought, water-starved trees have lost their ability to fight off bark beetles and disease, Cameron Barrows said. This is compounded by the rapid warming of winter temperatures, caused by global warming, which would turn the winter season into a continuation of their breeding season, he said. Cold winters would kill or at least slow the growth of tree enemies like the bark beetle and bacteria. Now their numbers can multiply significantly in their normally dormant season, Barrows said.

  • Climate Change Hits Turkey's Richest Highland, by Daniel J. Pierce, Daily Sabah, 9 November 2016.
    EXCERPTS: The people living in the highland villages of Kozak, located in the Aegean province of Izmir, enjoyed the highest per capita income in Turkey until eight years ago, when climate change hit their pine nut production. Nowadays, the villagers either make a meager living by working in stone quarries or mines. The villages are situated among dense pine forests, known by locals as the "green sea" and used to produce up to 2,000 tons of pine nuts, about 10 percent of global production... Many experts had investigated the reasons why the dramatic drop in pine nut production, Camgul said, adding, "At first everyone focused on bugs or fungus. At the end, the Izmir Forestry Department concluded that the cause was climate change."

  • Prehistoric Trees Could 'Future-Proof' Forests Against Climate Change, by Daniel J. Pierce, Motherboard, 24 October 2016.
    Explores the climate adaptation forestry work on British Columbia's Cortes Island by part-time resident (and "landscape artist") Oliver Kellhammer, who has been restoring a clearcut property he purchased with "formerly native trees", including Sequoia, Metasequoia, Redwood, and Cunninghamia.
         EXCERPTS: "We've been experimenting with growing trees [on Cortes] that have been extinct here for 50 million years and are still found in other parts of the world," Kellhammer told me. "It's an experiment to gauge whether the redwood, say, could be a replacement for the red cedar." Kellhammer had been planting Eocene trees in his garden on the island since 2002. In 2008, he got the chance to scale the project up when his friend, botanist Rupert Sheldrake, along with a co-operative of Cortesians, purchased a 60-acre clear-cut on the island. Kellhammer pitched the idea to Sheldrake, as he explained it to me: "Here we have an opportunity, Rupert, of a barren piece of land that's been terribly abused. Can we try to restore the land in a way that speaks to the future and to future climatic conditions?" Sheldrake was on board with the idea and agreed to bankroll the reforestation, according to Kellhammer. "Yes, we are playing God," he told me. "But we've already played God. The human species has changed the climate. I'm in the 'You broke it, you fix it' school, and we're trying to fix it." According to Kellhammer, the intention of this project was to start a conversation about how far we are willing to go to help forests adapt. "Do we let giant swaths of the landscape die [because of] things like the pine beetle? I thought that by starting this project, people would start asking what the appropriate response should be." While some people feel inclined to let the forests migrate on their own in response to the changing climate, we are on pace to see 50 million years' worth of planetary warming in about a century. Forests don't move that quickly. I mean the trees aren't just going to jump on people's cars and hitchhike up to B.C.," Kellhammer said. "It would take thousands of years." "We can't just sit back and hope it all works out. It's not working out," Kellhammer said. "I think we need to be moving species from more southerly latitudes to higher latitudes if we want them to survive." Seeing these strange trees grow on Cortes is a powerful reminder of just how much the climate has already changed. But it's also a reason to be hopeful. "The best candidates are the coast redwood and the giant sequoia. Those two are, hands down, very happy on Cortes Island," Kellhammer said.
         Note: See also Kellhammer's website for more detail on this paleoclimate restoration project. EXCERPT: Metasequoias in particular have done spectacularly well and a couple of my ten year-old specimens have reached over 8 metres in height. These are amazing trees — deciduous conifers long though to have been extinct and causing a sensation when they were found surviving in a remote part of China back in 1944. Yet their fossil remains are distributed throughout the Northern hemisphere, from mid latitudes right up to the high Arctic where their deciduous needles might have conferred them an advantage during the darkness of the polar winter. Work on this "Climate Change Forest" is ongoing and our hope is that the successes and failures in establishing the various tree species will yield some useful information on the future of forests under conditions of rapid global warming. Perhaps some of the trees might possess a kind of genetic memory and will once again flourish in BC's forests as they did so many aeons ago. If that is the case, the reintroduction of these Eocene survivors might prove part of a larger strategy to manage the climate cataclysm that has only just begun.

  • The State of Canada's Forests: Annual Report 2020, Natural Resources Canada.

    EDITOR'S NOTE - Canadian foresters present the importance of helping forests move poleward without ever using the standard terms in use by conservation biologists pondering whether and when to move threatened species. In the entire 88 pages, the term "assisted migration" appears only twice — and that entirely within the titles of papers in the citations section. "Assisted colonization, facilitated migration, and managed relocation" do not appear at all. One can surmise that not only is this a practical way to defuse debate, but because the emphasis is on retaining healthy forest canopy — irrespective of species identities — there is no reason to choose a term created in the context of concern about species-specific tree wellbeing.

       "...Traditionally, foresters have used local tree seed for planting seedlings, as local populations were generally thought to be best adapted to the climate conditions of the site. However, with a rapidly changing climate, these local populations may not be able to adapt quickly enough, and while well-established adult trees can often withstand increased stress, seedlings are highly vulnerable. If forest managers know which seeds and seedlings from the southern portion of the range would thrive in the changing northern conditions, they can strategically select the hardiest and best-adapted for planting."

    SEE ALSO the frightening news report of Canada's aggregate forests shifting already from carbon sink to source: "One of Canada's biggest carbon sinks is circling the drain", by Barry Saxifrage, 7 May 2021, Canada's National Observer.

  • Assisted tree migration in North America: Policy legacies, enhanced forest policy integration, and climate change adaptation, Scandinavian Journal of Forest Research, by Adam Wellstead and Michael Howlett, October 2016.
    ".... As Table 2 shows, in the case of forest management practices on both sides of the border, many forestry agencies have policy instruments, particularly comprehensive regulations, in place which are dedicated to reforestation practices and also specify which species that can be replanted. These instruments generally restrict ATM ["assisted tree migration"] activities, however. Currently, tree species reforestation regulations generally allow planting only to be carried out within an existing species range in order to improve forest productivity and health but without fundamentally affecting the tree composition of forestlands.
         In Canada only three revisions to policy calibrations have been made. In Alberta, seed transfer guidelines have extended current reforestation guidelines northward by 2 degrees latitude and upslope by 200 m (Williams and Dumroese 2013). In Quebec, Ste-Marie (2014) noted that seed transfer models that take climate change into account have been developed and are being used to determine the locations where seedlings produced from seeds grown in seed orchards can be planted for the best chances of survival and growth to maturity. British Columbia's Ministry of Forests, Lands and Natural Resource Operations also recently allowed seeds of most species in most regions to be planted 200 m higher in elevation (Ste-Marie 2014). However, these changes were not directly attributable to climate change related goals and amounted to very minor adjustments to the status quo with little impact or effect on forest policy integration across sectors or jurisdictions.
         The only significant policy change attributable to climate change to date in either the US or Canada has been the much publicized amendment of the British Columbia's 'Chief Forester's Standards for Seed Use' which were developed to enable the movement of western larch from southern to northern parts of the province in 2010 (Government of British Columbia 2010; Klenk and Larson 2014). These changes took place in concert with considerable research undertaken by the Future Forest Ecosystem Initiative (FFEI) that was established by the Province�s Chief Forester..
         ... Such reform may come from outside of ossified existing policy regimes, through various kinds of bottom-up and top-down policy leadership. An example of the former, for example, occurred in Florida recently in the actions of the Torreya Guardians group which, for nearly a decade, has taken a variety of assisted migration actions to protect the endangered Torreya taxifolia. Motivated by climate change impacts and possible extinction of this conifer species, this group of botanists and amateur enthusiasts outpaced forest services in planting seedlings 400 miles north of the torreya's current natural range to sites in the North Carolina mountains (Economist 2015). Similarly, in what could portend an important development in this area, for example, the Forest Products Association of Canada (FPAC) stated that assisted migration of tree species is an important approach to 'adapting our sustainable forest management to climate change' (FPAC 2016). Such citizen and industry-led science and advocacy may provide a vehicle for policy patching in the face of stymied top-down policy dynamics and provide an additional avenue to reform and enhanced integration in the sector."

  • IUCN SSC Guidelines for Assessing Species' Vulnerability to Climate Change, (book in pdf) edited by Wendy B. Foden and Bruce E. Young, September 2016.
    Section 2.2 offers a very useful summary of the bases and distinctions among three "Climate Change Vulnerability Assessment Approaches." The three types are: (a) Correlative approaches, (b) Trait-based approaches, and (c) Mechanistic approaches. The section then ends with discussion of various "Combination approaches" that blend two or more of the approaches. Note: Whether or not assisted migration is a management tool under consideration, "vulnerability assessment" is a crucial first step for any climate-induced adaptation strategy.

  • Rethinking legal objectives for climate-adaptive conservation, by Jan McDonald et al., Ecology and Society, 2016. Note: This lengthy article focuses on the situation in Tasmania, however, the conundrum about whether and how wilderness areas can be assisted in climate adaption applies to the USA as well:
    EXCERPT: Valuing "wildness" and in situ conservation. The prominence of the Tasmanian Wilderness World Heritage Area in the Tasmanian framework places explicit value on the importance of nature in an undisturbed state. This is also the case in the threatened species law: the first objective of the TSPA is to ensure that "native flora and fauna in Tasmania can survive, flourish and retain their potential for evolutionary development in the wild". "Wild"is defined as "an independent, unpossessed or natural state and not in an intentionally cultivated, domesticated or captive state regardless of the location or land tenure" (TSPA s3).
         International, national, and state law all emphasize the importance of in situ conservation. However, with the rapidity of climate change, coupled with habitat fragmentation, likely to undermine the capacity of some species to independently evolve and/or adapt, human intervention in the form of restoring large-scale ecological connectivity and/or assisted colonization is likely to become increasingly necessary (Braverman 2014). Terms such as "wild" and "natural" are therefore increasingly unhelpful in directing conservation outcomes under anthropogenic climate change. This is not to say that protecting areas of "wilderness" is not valuable. Rather, it may become necessary to adjust our understanding of "the wild" by accepting a higher level of human influence in the form of active conservation management, in order for some species to persist in those places. In this regard, Meine's (2015: 91) "relative wild: the degrees of wildness and human influence in any place, and the ever-changing nature of the relationship between them over time" may provide a useful terminology.

  • Managing Climate Change Refugia for Climate Adaptation , by Toni Lyn Morelli et al., PLOS one, 10 August 2016.
    Editor's note: Beginning in about 2014, there has been a push for identifying "climate refugia" as possible locales that are naturally buffered against climate changes generally expected in their broader region. This is a 15-author review paper. "Assisted migration" is referred to twice in this paper — as by 2016 there was no longer any real debate about whether assisted migration is a valid conservation tool in this century of rapidly changing climate, but rather under what conditions it would be one of the climate adaptation tools recommended. Here are the two instances of usage: (1) "One general management action could be to reconnect climate change refugia to each other and nearby non-refugia habitats so as to improve long-term access to refugial areas. This can be done passively by protecting or enhancing connectivity corridors and restoring or protecting nearby non-refugial habitats, or actively by seed banking or captive rearing for future release (i.e., assisted migration). (2) Decisions might need to be revisited if changes in physical and ecological processes degrade refugium properties, or as management goals change and the protection of other resources becomes more urgent. Depending on the situation, management actions could focus on improving resistance of refugia (e.g., habitat restoration) or strategies for assisted migration of prioritized species."

  • Assisted Migration in Normative and Scientific Context , by D.S. Maier and D. Simberloff, Journal of Agricultural and Environmental Ethics, August 2016. Editor's note: Whether one is pro, con, or variable about assisted migration, the sections of this article (prior to the Whitebark Pine case study) provide an excellent background overview, including key sources. The handling of the Whitebark Pine case study and the paper's conclusion section, however, depart from background to advocacy (against assisted migration) and often in stark rather than scalar judgment statements.
    ABSTRACT. Assisted migration (AM), an ecosystem engineering technology, is receiving increasing attention and significant support as a means to save biodiversity in a changing climate. Few substantive, or not obviously deficient, reasons have been offered for why pursuing this conservation goal via these means might be good. Some proponents of AM, including those who identify themselves as "pragmatists," even suggest there is little need for such argument. We survey the principal reasons offered for AM, as well as reasons offered for not offering reasons. As exemplified by the case for translocating whitebark pine, which may at first seem especially strong, we note the incongruence of framing the goal of AM in terms of "saving biodiversity," neglect of some crucial moral questions, marginalization of normative and scientific context when AM is cast as the lesser of two evils in a "crisis," doubtful validity and, in any case, marginal importance of arguments that AM projects ought to be undertaken, inconsistent use of scientific facts, and omission of science that counters sanguine assessments. All told — even in cases such as whitebark pine for which AM may seem most defensible — there is little reason to think that AM projects are good as means to "save biodiversity," or good as means to other goals that have accreted into arguments for these projects.

    INTRODUCTION (excerpts). Papers discussing assisted migration (hereafter, "AM") have proliferated — from virtually nil before 2007 to hundreds per year recently (Hallfors et al. 2014). Also known as "assisted colonization," "managed relocation," "species translocation," and other names, this type of project was initially proposed in a conservation context by Peters and Darling (1985, p. 715), who suggested that such projects might avoid extinction of populations or entire species facing climate change. This change, they observed, may outpace the ability of some species to sufficiently adapt in situ to new conditions — even if intensively modified for their benefit — or to migrate sufficiently far to suitable new sites. This original goal is now often characterized in terms of "biodiversity protection." However, ecosystem engineers already focused on rather different goals quickly saw AM as means to serve these, too. AM is now also proposed as means to preserve, establish, or enhance "ecosystem services." ... The econometric end of the spectrum of AM-facilitated goals is development of market-based goods, particularly in forestry (Pedlar et al. 2011), activities that differ little from longer-standing practices of establishing commercial tree plantations (Aubin et al. 2011). Back on the species conservation end of the spectrum, stripped of the requirement that the threat be specifically climate-related, similar conservation goals have long been discussed (for example, Dodd and Seigel 1991) in terms of head-starting (bolstering populations from captive-raised early-life-stage stock), relocation (moving organisms out of harms' way typically to another part of their historic range), repatriation (bolstering existing populations or reintroduction), and translocation (AM without the requirement for climate-change-induced stress).... Our focus is mainly on AM in the original, conservation sense of Peters and Darling (1985), as framed by many later proponents: "saving biodiversity" by translocating individuals of species or populations to sites beyond their historic range to stem their imminent demise because of human-induced climate change. However, thoroughness dictates attending to other goals added to arguments that start out about "conserving biodiversity." Many of our observations about the principal arguments on behalf of AM refer to the particular case of whitebark pine ("The Case for Whitebark Pine" section). That discussion is best understood with a prior understanding of the general terms of the AM debate ("The Terms of the AM Debate" section) and the fragmented normative and scientific context that frames it ("Missing and Hazy Moral and Scientific Context" section).

    THE TERMS OF THE AM DEBATE (excerpts). The last decade's plethora of concept and commentary papers on AM show it to be largely accepted as a legitimate conservation tool — even by skeptics who merely insist that AM meet certain ecological conditions (Hunter 2007; McLachlan et al. 2007; Hewitt et al. 2011). The debate saliently centers on the fact that AM targets single species rather than entire ecological communities and that it retreats from the traditional conservation approach of conserving species by maintaining the environments in which they currently thrive. However, few commentators touch on the central normative question: Is there moral warrant for rearranging the planet's biota as a response to climate change? This reticence may seem perplexing in light of ubiquitous discussions about how to decide whether to AM or not to AM. Some authors even delineate decision procedures with flow diagrams (Hoegh-Guldberg et al. 2008) or decision-tree graphs (Richardson et al. 2009), which, they allow, may sometimes compute the answer, "undertake AM." But they offer little basis for thinking that the computational inputs are normatively important and hence that a computed decision "to AM" is right in the sense of "morally warranted."
         Several errors may lead to misplaced confidence in decision procedures. One arises from the mistaken belief that we ought to choose what we would choose by following a good or even ideally rational deliberative procedure. This belief gets the normativity backwards (Parfit 2011, pp. 62-63). In fact, we ought to choose what we have most reason to choose. While we may be more likely to uncover the most important reasons and reach a correct conclusion if we deliberate in some ideally rational way, the method is not what makes it right or how we know we've got it right. Another error, correlative to the last one, arises in pervasive calls to include as many "stakeholders" as possible in deliberations ... But contrary to what these and many others apparently presume, stakeholders' views regarding some action are not importantly relevant to whether the action is morally warranted. In fact, including certain stakeholders can, and not infrequently does, lead to morally perverse decisions.... But no amount of sociological investigation into what people desire or what cultures sanction can reveal whether what is desired or sanctioned is worthy of these attitudes.
         ... Even if the population of an organism in question would assuredly perish if let be, even if it would assuredly flourish elsewhere as an evacuee, and even if the ecological changes that it brings to its new home would assuredly fall within the tolerances of some AM engineering specification, these considerations alone would not tell us whether we ought to undertake it. That determination hinges on the answers to multiple normative questions. These include, most basically, whether we ought to act to continue the existence of a population (or species) on these terms. No amount of biology alone can answer this or related normative questions.
         ... These analyses attempt to account for the likelihood of beneficial and harmful outcomes to arrive at some expected net value for an AM project, while the term "risk" is used to mean "the likelihood of some harmful effect." However, while these assessments speak of AM's harms and benefits, those proposing them hesitate to offer any reason to think that what they call the "benefits" of AM are good things, worthy of bringing about; or that certain other consequences of an organism's translocation are "harms" that we ought to avoid.
         ... Schwartz et al. (2012) bring attention to some of the legitimate "ethical challenges" of their paper's title — perhaps most usefully to moral hazards (Schwartz et al. 2012, p. 727), which most others ignore. But beyond that, they do little more than summarize the terms of the debate as it has actually played out without attending to their many deficiencies. Among those who signal awareness of the need to place AM on some firm normative footing are Minteer and Collins (2010, 2012) and Minteer (2012). Indeed, Minteer and Collins (2010, p. 1801) see themselves as pioneers of a "more dynamic and pragmatic approach to ethical analysis"... Minteer and Collins urge that we forgo any attempt to answer "in the abstract" — that is, by valid normative reasoning from credible, generally endorsable, and generally applicable moral principles — whether AM serves any worthy goal or, if it does, whether it is a morally respectable practice. This exhortation overlooks the fact that a good way to perform an act that we ought not to perform is not equivalent to performing a good act. Minteer and Collins are nonetheless likely correct to think that their pragmatic ethics melts away many of AMs complexities by focusing on "realistic options," a phrase that appears to mean "what ecosystem engineers can (rather than should) do." Assessing our capabilities is often simpler than assessing our moral permissions and obligations. Minteer and Collins are hardly alone in calling for a "pragmatic" approach to AM — either out of apparent unawareness of the importance of ensuring the moral worthiness of projects or because normative principles bearing on AM just seem too difficult to work out. Among the popular interpretations of this sentiment is the view, expressed by Hewitt et al. (2011) (above), that one should simply determine what stakeholders want.
         ... Not infrequently (as in the case of whitebark pine), "performing an ecosystem function" is offered as the account of what is good, and "conducing to ecosystem integrity" is offered as the missing reason for why it is good. But these stock answers merely pass the normative buck or raise without answering other, equally difficult questions: Why is it good that an ecosystem have certain functional properties but not others? What special goodness arises from the fact a particular organism plays a causal role in some functional property? And insofar as �"ecosystem integrity" is taken to mean "the condition of retaining certain state and functional properties," why is this sort of ecosystem stasis good? ...

    MISSING AND HAZY MORAL AND SCIENTIFIC CONTEXT. Few papers engage substantively with AM's important normative questions — even when representing that they do. Albrecht et al.'s (2013) titular promise to address "the ethics of assisted migration" devolves into "arguments" that largely consist of repeating the phrase "we argue that..." This phrase, it soon becomes evident, means "we suppose, without giving reasons for supposing, that..." In this way, they (p. 835) "argue that" species have "intrinsic value" and "argue for" rules of intrinsic value transfer — for example: "species... have intrinsic value as do, by implication, the ecosystems/habitats within which they live."
         ... The most comprehensive normative assessment of AM remains that of Sandler (2010, 2012, 2013). The most significant effort to supplement and challenge Sandler's work is the attempt by Palmer and Larson (2014) to mine the high-profile AM proposal for whitebark pine for additional normative perspective. We address the case of whitebark pine in the next section. However, even counting these best efforts, important normative questions connected with AM remain unasked; and important normative context is obscured by virtue of how questions that are asked are framed. One would be hard-pressed to find a paper on AM that does not set the context as a world in which the changing climate is devastating biodiversity. In this setting, AM is billed as an important remedy and, not infrequently, a principal means to stay a train wreck of extinctions. Yet there is little reason to think that even the most extravagant deployment of AM technology could live up to this billing and much reason to think it cannot.
         Even if all nature conservation resources on the planet — scientists, time, money — were channeled entirely into AM projects, and even if every one "succeeded" in the sense of establishing an appropriate population — not too many, not too few — in target locales, no one could credibly claim that this would affect more than a handful of species.. The false billing reflects widespread failure to take into account the true ambit of even one AM project (Dodd and Seigel 1991; Dodd 2005). The thought that AM may play a major role in "saving biodiversity" is credible only on the presumption that the bulk of the effort consists of transporting and releasing or planting organisms; then repeat for the next project. In reality, those sizable efforts may be dwarfed by preparatory investigations combined with indefinitely extended monitoring and management of the target locale for the sought-after, appropriate-sized population of translocated organism that achieves true establishment without invasiveness. Preparatory investigations could take many years; ongoing monitoring must span multiple generations of the translocated organism. For some organisms (such as whitebark pine) this might exceed the span of a biologist's career.
         ... These considerations point to considerable shrinking of AM's capacity to save species or populations. This circumstance gives rise to a moral question that has received little or no serious attention: On what morally respectable basis might the necessarily tiny contingent be selected?... no AM project (or no responsibly conducted one) can be launched by just grabbing available plants or animals from one locale and then installing them in another. The deliberative space required for planning projects with such scope, complexity, and requisite commitment is also ample space for deliberating about which species (or populations) we ought to haul aboard. We do have time to ask: how should we choose in a morally respectable way?
         AM advocates are not without answers. One is: on the basis of services they might provide to people. Of course, this response eliminates almost all species and populations, including essentially all that are rare or endangered. Another is: on the basis of how strongly public sentiment can be mobilized to back such a formidable undertaking. This answer would likely finger large, charismatic animals.... Bypassed as well would be the vast majority of organisms that are not animals — including most plants (or any that lack iconic status) and fungi, not to mention other eukaryotes that barely register in public awareness — slime molds, flagellate protozoa, foraminifera, and brown algae — and non-eukaryotes: the multitude of bacteria and archaea. If bolstering biodiversity is truly the goal, it is difficult to believe that a scientifically credible and morally respectable basis for selection is substantial contributions to the service economy or public popularity.
         There may be other answers. But the very act of pitting one species or population against others as more worthy for a place on a life raft itself raises vexing moral questions. Without being asked and answered, yet more moral context falls away. Some, such as Hewitt et al. (2011), even explicitly deny the need for "generalizable valuations of species." Another morally weighty, yet almost universally overlooked, problem concerns the legitimate scope of AM's application. If sanction for AM is conditioned on its "saving biodiversity from the effects of human-induced changes in the climate," then its warrant would not extend to species or populations destined to wink out as a consequence of other "insults," or even to climatic changes that cannot be attributed to humans. ... However, routine disregard for what is involved in meeting this epistemic requirement fits the broader pattern noted above: minimizing the investigative burden relating to AM projects, and minimizing or disregarding burdens of monitoring and management that may span generations of ecosystem engineers.
         These above-mentioned deficiencies — mischaracterizing the proposition of undertaking AM projects in normatively and scientifically important ways and leaving holes in the fabric of AM's moral and scientific context where normatively and scientifically important questions should be asked — may be symptoms of moral hazards latent in its "state of emergency" logic: (1) biodiversity is in crisis because of climate change, (2) crisis conditions force dichotomous choices between evils, and (3) because it is a crisis, we must choose the lesser evil posthaste. The principal lesser-evil dichotomy — explicit or implicit in this framing — encompasses two propositions: (a) Either we pursue AM projects or face losing many species. And (b) "saving biodiversity" via AM (according to this logic) is better — a lesser evil — than converting natural landscapes into eco-engineered ones.
         This would be a grim choice indeed. It is therefore fortunate we are not actually reduced to it. Both (a) and (b) are false as exclusive disjunctions: Regarding (a): there are choices other than pursuing AM projects to spare species and populations, if and when we have decisive reasons to do so. Most obviously, this often involves paying more serious attention to the many (above-mentioned) factors other than a changing climate that may be pushing species and populations to the brink. As for (b): it is false by virtue of embedding the false assumption (discussed above) that AM may "save biodiversity" or even play a significant role in achieving that goal. Proposition (b) is especially insidious because it rationalizes the eco-engineering of landscapes by merely and falsely posing eco-engineering projects as necessary means for avoiding a bad state of the world. In this way, it subverts unencumbered consideration of all the reasons that might make a world in which eco-engineering is allowed on this or similar pretexts a bad world indeed. Playing the crisis card also has the effect of appearing to justify short-circuiting moral deliberation and carefully considered science — in other words, suspending the customary norms and requirements of responsible action....

  • Climate refugia and migration requirements in complex landscapes , by David R. Roberts and Andreas Hamann, Ecography, 2016. Editor's note: The term "assisted migration" appears 10 times in the journal article. Excellent range projection maps for all 24 tree species are available online in the appendix.
    ABSTRACT. All of today's species have proven their ability to cope with climate change during the glacial-interglacial cycles of the Quaternary, but future migration requirements may be different regarding speed, direction, geographic barriers, and availability of nearby climate refugia. Here, we contribute a landscape-level climatic analysis of postglacial vs. projected future migration requirements for 24 common western North American tree species. Using a recently developed velocity of climate change algorithm, we quantify required migration velocities for all populations of species to track climate habitat, based on projections from general circulation models for the 2080s and the last glacial maximum, 21 000 yr ago. Specifically, we ask if nearby climate refugia exist for at least some populations within species ranges and whether the current landscape position of species imply qualitatively different migration requirements in the future compared to those during glacial-interglacial cycles. Results showed that velocities to reach the nearest climate refugia in the future still exceed the fastest reconstructed post-glacial migration requirements, but not by orders of magnitude. Regarding landscape positions, we find a low correlation among past and future migration requirements, suggesting that qualitatively different migration patterns may emerge in the future for some species. Species identified as occupying landscape positions requiring disproportionally faster migration requirements in the future include whitebark pine, pinyon pine, and coast redwood. We discuss uncertainties of our analytical approach as well as implications for human-assisted migration and conservation action to address climate change.

  • Planning for assisted colonization of plants in a warming world, by Alessandro Ferrarini et al., Scientific Reports, 27 June 2016.
    Excerpt: Results raise one main question: are assisted colonization activities worthwhile if they are only expected to be successful in the short or medium term? It is evident that a modelling approach like that proposed here can provide the basis to rigorously examine this question. It has been suggested that the success of assisted colonization activities also involves the population dispersing seeds into the surrounding countryside and producing satellite populations. Our results indicated that not only is C. foetida likely to disappear from the peripheral area in the future due to climate scenarios, but also that in the N-Apennines mountain system (Emilia-Romagna region) there will be no further suitable sites for this species. In other words, producing satellite populations in surrounding areas is unlikely for C. foetida even under current climate conditions, and it will become increasingly improbable as time goes by.

  • Ravaged Woodlands, by staff of The Economist, 9 July 2016.
    Editor's note: This lengthy article excels in presenting the scale and frightening implications of climate-induced bark beetle outbreaks and wildfires in wild forests of western North America, focusing on California. This is a superb introduction and/or review of the impact of climate change on forests and forestry for the public and experts alike. Although only a few paragraphs deals with assisted migration as a climate adaptation strategy, the article as a whole establishes the need and the difficulty in compelling terms.
        EXCERPT: Mitigating those effects would require a massive intervention to clear dead trees and plant new ones, which is currently unthinkable. Last year the U.S. Forest Service spent more than half its budget on firefighting, to the detriment of its ongoing effort to thin some 80 million acres of dangerously overgrown forest. By 2025, the service estimates that 67% of its budget will be consumed by fires. Even if the lost forest were replanted much of it would fail: because species distribution is changing as temperatures rise. Broadly speaking, a warmer, drier climate should force trees uphill and to higher latitudes; the Ponderosa pine will climb from the montane to the subalpine zones, displacing or finding refuge among white firs and lodgepole pines. Anticipating this, foresters are replanting trees at the highest elevations of their range. The effect of fire and bug-death has, in this way, created opportunity for a massive experiment in tree migration and regrowth. But it may not be a predictable, or happy, transition. Whether a species can migrate may depend as much on factors such as soil type, distance from a seed source, the pace at which it reaches reproductive maturity and the vulnerability of higher-elevation vegetation to infiltration as on temperature alone. The rate of warming will be even more important. It took the Ponderosa pine 11,000 years to migrate from New Mexico to Wyoming after the most recent Ice Age: it will not keep stride with rapid warming. A study of USFS data suggests nearly 60% of tree species are experiencing range contraction at both their northern and southern boundaries. Only 20% are making the predicted northward shift.

  • "Agency launches long-term spruce, aspen treatment plan by Dennis Webb, The Daily Sentinel (Grand Junction, Colorado), 6 August 2016.
    EXCERPTS: Responding to habitat shifts resulting from climate change will be one of the considerations for the Grand Mesa, Uncompahgre and Gunnison national forests as the Forest Service embarks on a new forest treatment project over the next eight to 12 years. Its new Spruce Beetle Epidemic and Aspen Decline Management Response project is a response to about 223,000 acres where spruce have died from beetle infestation on the forests, and 229,000 acres that have been affected by what's called Sudden Aspen Decline, over a decade.
         The Forest Service expects mortality in spruce stands "to continue at relatively high levels for several years to come," according to the final environmental impact statement for the project. In 2009 the detection of new areas of aspen decline dropped considerably, but stands already affected continue to decline, and the Forest Service expects the aspen and spruce problems to be exacerbated in the future by climate change.
         While the new forest treatment plan is intended to also address other goals like reducing safety hazards such as falling trees and increased wildfire danger, improving forest resiliency is a key goal. That includes trying to make the forest resilient in the face of a changing climate. "In the climate change world, that's called adaptation measures — basically trying to adapt the forest to a changing climate," said Jim Worrall, a Forest Service forest pathologist who helped do the climate modeling. He said quite a few outcomes of the management response project "could help adapt the forest to a warmer and potentially drier climate."
         Worrall said where logging of beetle-killed spruce occurs, that could provide an opportunity for regenerating those acres with more aspen, or other trees more tolerant of an expected hotter, drier climate, such as Douglas fir, ponderosa pine and blue spruce. "I think at first it's going to be baby steps because people are a little bit cautious, and reasonably so, about completely changing a (forest) cover type," he said. Where there's spruce-fir forest, it might be crazy to start planting pinon-juniper now, even if models say it would be good pinon-juniper habitat by the end of the century, he said.

  • Also by Dennis Webb, 6 August 2016, "Cycle of decline: Estimate portends big changes in makeup of forests".
         EXCERPTS: Lovers of the local high country could find a recent projection of a warming world's impacts on area forests to be chilling. By 2060, according to a U.S. Forest Service estimate, almost all of the Uncompahgre Plateau would no longer be able to sustain growth of new aspen and spruce, meaning that the plateau could be virtually aspen- and spruce-free by century's end after the remaining trees die. On the southern and eastern fringes of Grand Mesa, aspen also could see sizable losses of suitable habitat by 2060, with spruce habitat largely slipping into a threatened category across the mesa, meaning the future climate isn't favorable to sustaining it.
         The modeling used by the Forest Service found that 52 percent of current aspen distribution across the forests would be in the lost habitat category by 2060, and 42 percent in the threatened category, "meaning it is conceivable that 94 (percent) of current aspen distribution may not continue into the next century," the Forest Service says in its final environmental impact statement for the project, released earlier this year. Aspen habitat generally would be lost at low elevations, especially on south-facing slopes, with the western West Elks also sharing in that habitat loss. Some of that habitat loss could be offset by newly emerging habitat at higher elevations. But Samantha Staley, a Forest Service planner, says while the climate may shift to support the species at a higher elevation, that doesn't mean that other ecological components necessary to support the species will be present. Some higher elevations may not be suitable thanks to things such as poor soil conditions or rocky scree slopes. The model projects a 22 percent loss of current spruce distribution, and that 58 percent of distribution will become threatened, meaning that 80 percent of current distribution may not continue into the next century.
         The model is based on an assumption of a continuing warming trend on the forests. The statement says temperatures are expected to rise 5.4 to 7 degrees by 2040-60. Higher temperatures could foster more spruce beetle outbreaks, further stress trees because of increased drought and result in more damage from wildfire. "I think what those maps show is stunning,"Zukoski said. "I think those kind of maps are extremely helpful because they permit people to see in their areas, places that they care about in their backyards, what the world's going to be like for their kids and grandkids, and for themselves if they live long enough. I think giving people that picture over that longer term really helps them understand how dramatic the impacts of climate change could be if we don't work darn hard to get a handle on it."
         Meanwhile, a 2006 model created by researchers led by Gerald Rehfeldt, who worked at the Forest Service's Moscow Forestry Sciences Laboratory in Idaho before retiring, projected a 47 percent drop in suitable spruce habitat in the western United States in the decade around 2060, and a 72 percent loss by 2090. The Forest Service statement says that for the forests, that model was rebuilt using local data, more "topographical predictors," newer global climate models and carbon scenarios, and higher-resolution climate data. Its resulting projections are an average from three climate models and three greenhouse gas emission scenarios. "These are models, which necessarily include some amount of error," Staley said. She said it's based on the best available information today, and the Forest Service understands the science will be a lot better in a decade. "We have to look at it as it's not the gospel, but it's the best available scientific information that we have today about where vegetation may be headed in the future," Staley said.
         Jim Worrall, a forest pathologist with the Forest Service�s Rocky Mountain Region 2, which includes Colorado, said Rehfeldt worked with him and others to localize his methods, and they developed a model for 13 tree species in southwest Colorado, including spruce and aspen. Worrall said one of the biggest uncertainties pertains to the climate models, because there are so many models and carbon scenarios to choose from. He said the forest-habitat predictions the Forest Service came up with concern him and he hopes they're wrong, but they're the best idea researchers now have of what the future holds. "It's really a very objective process. There's really no subjectivity in the model development," he said. Interpreting the results to make them simple and easy to digest can be a little subjective, he said. "But we've been pretty conservative in that," he said, adding that the predictions are based on what the models are telling researchers, and those models are built on a lot of data.
         Staley said the agency is compelled to use that science in its planning and efforts to manage sustainably into the future, and current research acknowledges that warming will result in shifting of not just animals but trees in terms of habitat. "The environment is changing and that's why we're using as much information as we can to make the best decisions," she said. Forests are always changing, thanks to factors such as insect infestation and wildfire, and cycles such as aspen thriving first in disturbed areas and later being succeeded by other types of trees. But now the Forest Service is learning more about how that's happening in the context of "pretty rapid climate change," and what the forest may look like in that context, Staley said.
         While every generation sees a slightly different version of a forest, future forests may be ones that people have never seen locally, she said. Rather than a mid-elevation forest shifting back and forth from aspen to spruce, it may shift to oakbrush. "And that's a new shift," she said. Oakbrush and mixed-mountain shrubs cover about a quarter of the Uncompahgre Plateau now.
         [Jim Worrall] said of the modeling's findings, "I think we need to plan for the worst and hope for the best, is what I suggest. But most likely even if the models are a little off, we're going to be looking at very different conditions in the future for our children and our children's children than we have now."
  • "Relocating Australian tortoise sets controversial precedent" by Dyani Lewis, news report, Science, 11 August 2016.
    EXCERPTS: [final 3 paras] Even if the tortoises prove benign, as Mitchell and Kuchling anticipate, Ricciardi fears that such trials set an alarming precedent. "Other people are going to be looking at [this trial] and they're going to be saying, 'OK, what about my species?'" he says. "I wouldn't like to spin that roulette wheel very many times."
         Assisted colonization has already been used for plant species, such as Torreya taxifolia, an endangered conifer native to the Florida panhandle. Conservationists in New Zealand are also weighing the strategy to save the endangered hihi, or stitchbird (Notiomystis cincta), which faces an uncertain future if not moved to cooler climates farther south.
         But Possingham doubts the floodgates will open any time soon. "It's not open slather," he says, and scientists will judge each proposed colonization on its merits. For Possingham, who thinks assisted colonization will become a "pragmatic" conservation tool to prevent extinctions, results of the trial can't come soon enough. "Unless we try these things, we'll never learn how to do them, so the sooner the better."

  • "Secret Wollemi pine population offers hope for species' survival" by Marcus Strom, news report, Sydney Morning Herald, 26 August 2016.
    EXCERPTS: ... Now those trees hidden deep in the Blue Mountains [Australia] are under threat. One of the four stands of Wollemi pine has developed a fungal disease, likely from unauthorised hikers carrying in the Phytophthora mould."
         ... The ancient population of Wollemis is also missing middle-aged trees, which is concerning the botanists.... So in secret, Dr Zimmer, Dr Offord and their colleagues in 2012 planted a grove of trees in a second location to see how well the species coped with being moved in a process botanists call translocation. Fairfax Media was given the first access to the secret Blue Mountains site to see the young trees thriving on a steep rainforest canyon near a pristine mountain creek.
         ... But given we can grow the trees in our gardens, why save them in the wild? "It's not the same as having a wild population," Dr Zimmer said. "You wouldn't be happy just having pandas or whales in captivity. Ecological diversity is as important in the plant world as it is for animals. Humans have been responsible for so many extinctions. If we have it in our power to save a species, why shouldn't we?"
         She and her team planted 191 trees at 30 sites with varying degrees of light and moisture. Of those, 29 have died, most of these due to infection from Botryosphaeria fungi. These were mostly in damper and darker locations. Most of the others are thriving, giving botanists valuable information about the best conditions for them to grow. "They're doing much better in the higher-light sites," Dr Zimmer said. Dr Zimmer recommends future translocations should happen at sites with good light availability under protective tree canopy. She also recommends planting seedlings in future, "to account for the possibility that previously undetected genetic variation may emerge from seeds."
         Dr Offord said that with the lessons learned from the experimental site, the next step will be to establish bigger populations in national parks. She said: "Low genetic diversity might mean Wollemi pines will be less able to evolve in response to change, such as environmental change or exposure to disease. For example, we know the Wollemi pine is particularly susceptible to high temperatures." "To help the Wollemi pine in the face of predicted climate change, we will select cooler translocation sites — sites which are predicted to remain within the Wollemi pine's known temperature tolerance range [between -10 and 35 degrees] for the next 100 years."

  • "Uprooted: How climate change may kick off an artificial migration of trees" by Alessandra Potenza, news report, The Verge, 22 August 2016.
    EXCERPTS: "The problem with trees is they can migrate only very slowly," says Sally Aitken, the director of the Centre for Forest Conservation Genetics at the University of British Columbia. "They really can't move quickly enough to keep up on their own." Climate change has already altered how we approach forest management. . . Park managers will soon need to find new ways to protect trees, whether it's with assisted migration or some other solution. "A national park has generally been a system where we take a hands-off approach to management," Mark Schwartz says. "If anything, trying to restore ecosystems to some historic, pristine state." But now, park managers are struggling to find new ways to preserve the nation's forests.
         Some people are taking conservation in their own hands. Connie Barlow, a retired science writer and amateur ecologist, launched her own assisted migration program in the US. Her goal is to save Torreya trees, which only survive in northern Florida in their native range and are listed as endangered under the Endangered Species Act. In early 2000, Barlow acquired Torreya seeds and seedlings from botanical gardens and nurseries, and began planting them in private forests and yards in North Carolina. Since then, she's also planted Torreya trees in Virginia, Tennessee, Ohio, and New Hampshire, with the help of other volunteers. "Citizens need to step forward and we've shown we can do it," Barlow says. "What's undeniable now is that climate change is happening so rapidly ... that even common species are going to have to be moved by humans, intentionally."
         Some ecologists, however, are wary of her actions, and accuse her of acting too fast, without conducting the proper research. "I thought it was very premature," Schwartz says. "We have no indication yet that management will be able to save the species within its native range. It is declining toward extinction." Others support what Barlow's doing. Torreya trees are very "low risk" — their seeds don't disperse easily, so they're not likely to become invasive species, says Gray-Steinhauer at the University of Alberta. "As far as a conservation effort, it's appropriate," she says. "It's a good strategy."
         In the US, forest managers are considering a less controversial form of assisted migration that has to do with seed selection, according to Christopher Woodall, a research forester at the Forest Service. Instead of moving trees north, forest managers are selecting seeds of the same tree species that live in warmer climates and are therefore more resistant to droughts.
         Whatever strategy is used, most conservationists agree that something needs to be done. Saving trees means much more than just saving forests: it means saving the habitat where many other species live in, it means saving the roots that regulate water flow, and the mechanisms that take in carbon dioxide and create the oxygen we need to live. "Doing nothing, we lose the species," says Gray-Steinhauer. "Doing something, we take a risk but we don't know for sure. So you have to weigh out those pros and cons."

  • "Plants' native distributions do not reflect climatic tolerance" by Tierney Bocsi et al., 2016, Diversity and Distributions.
    Editor's note: A key problem for some plant species is using the bioclimatic envelope that is derived from the species' current range as the assumed matching climate for "fundamental niche" (v. the often smaller "realized niche", owing to dispersal barriers or Holocene lags in geographic range shift). This paper assesses 144 native plant species in America and found that, by counting horticultural plantings outside of native range, more than half registered significant lags in fully occupying their fundamental niche:

       "Many species would already be able to successfully establish outside of their native ranges, even before climate changes. The latter finding could support conservation strategies like managed relocation (Richardson et al., 2009), particularly for slow-growing, long-lived species like trees that might require planting well in advance of shifting climate conditions (Sax et al., 2013).

  • "How Climate Change Will Transform the National Parks' Iconic Animals and Plants", by Ker Than, Smithsonian Magazine, 8 August 2016.
    EXCERPTS: There was a time when the notion of letting prized native species die out seemed heretical. Now the agency is bracing for the possibility that some of the species under its care simply won't make it. It is also openly discussing the possibility of "assisted migration": manually relocating some animals and plants if it turns out they can't survive within the park's changing landscapes. These kinds of last-resort actions are controversial even amongst conservationists, but the NPS believes it is time to consider implementing them one day. "We don't rule out managed relocation in the future," says Patrick Gonzalez, the agency's principle climate change scientist. "But there are a lot less costly and less risky things we can try first."
         Faced with the possibility of losing one of its most iconic symbols, the park service must now consider what lengths it is willing to go to save the giant sequoias. One of its options is assisted migration, also known as managed relocation or climate translocation. Last year, NPS scientists used this technique to move bull trout in Montana's Glacier National Park. The researchers transferred trout from a lake where their numbers were dwindling—as a result of warming conditions and predation from another invasive trout species—to a higher-elevation lake that was cooler and free of predators.
         A sequoia relocation project in California would be even more ambitious. "We managed the giant sequoia forests now in such a manner that they can reproduce, but do we know whether or not that particular niche will allow those trees to mature in the future?" Jarvis says. "Is there a place in the Southern Cascades, as opposed to the Sierras, that we should be thinking about planting giant sequoias so that they'll still be around a thousand years from now? That's the way we've got to be thinking. We are in the perpetuity business here, so that's the space that we're beginning to explore."
         Christy Brigham, chief of resources management and science at Sequoia and Kings National Park, says the NPS's plans for assisted migration of giant sequoias are still purely speculative. "I would say we are at least five to ten years away from having to decide whether we need to take that step," Brigham says. "So far, a warming climate hasn't really been hurting the giant sequoias," adds Stephenson.
         Another drastic option is to transplant pikas into parks where the animals once existed but are not currently found. "Great Basin National Park is a place that looks like it could support pikas," says Tom Rodhouse, an NPS ecologist who headed the Pikas in Peril project. "But if we do that, it's controversial. These are really interesting conversations, and I think the park service is going to have many more like them in the coming decades."
         NPS director Jarvis says that if the parks are to survive another century, there is no question they will have to change. He gives the example of the iconic Joshua Tree National Park in California. "We may not be able to maintain Joshua trees in Joshua Tree National Park, but that doesn't mean that Joshua Tree National Park is somehow devalued," he says. "It will just become home to something new."

  • Making the Transition to the Third Era of Natural Resources Management by Nathan L. Stephenson, 1916, The National Park Service Centennial Essay Series
    EXCERPTS using "assisted migration": "Some species may migrate northward out of a park and onto adjacent lands, while others migrate into the park from the south (perhaps even by assisted migration). The net result is that the broader region in which the park is embedded maintains most of its native biodiversity. As parts of broader landscapes, parks will continue to play a critical role in maintaining native biodiversity...To be clear, the very real risk of unintended consequences means that intervention should never be taken lightly. Additionally, as we enter the third era we are likely to consider unfamiliar forms of intervention — like assisted species migration — that could carry novel risks."
        "Just as small experiments helped usher in the Leopold era, they can help us make the transition to the post-Leopold era. For example, we could potentially learn much from small, carefully conceived assisted migration experiments. Assisted migration experiments could initially be limited to those that could easily be undone, such as with tree seedlings (if needed, the trees could be removed well before they reach reproductive age). Any assisted migration experiment would be at least as much a social science experiment as an ecological experiment. How do NPS employees react to such proposals at the park, regional, and national levels? Are there policy roadblocks? How do the press and public react? At worst, planning for such experiments would help make the abstract real, and thus could open critical discussions within and between NPS and the public. Even if the main lesson is that large parts of the public are not comfortable with assisted migrations in national parks, this is valuable information."
        "It is normal to feel overwhelmed, at least initially, at the prospect of managing national parks and their natural resources in an era of rapid and unprecedented global changes. At a per- sonal level, many of us need to grieve the passing of the Leopold era and the loss of some of its ideals, and then become secure in knowing that the broad outlines of a new vision are beginning to emerge. Indeed, each of us can contribute to the evolution of this new vision. We do not need to figure everything out at once; we can start with small experimental steps, learning as we go."

  • "Climbers Are Scaling The World's Tallest Trees In An Effort To Save Them", by Dominique Mosbergen, Huffington Post, 7 September 2016.
    EXCERPTS: Assisted migration, or the process of moving plants to new habitats, is a contentious topic among scientists. Some believe that "playing God" in this way could have negative consequences to fragile ecosystems. Others, however, are adamant that such efforts are necessary to save species at risk of extinction due to climate change and other human impacts. Archangel and the Eden Project both fall firmly in this second camp. The two groups are now working together to bring "living archives" of trees to other countries worldwide. They hope to bring their propagation efforts to all seven continents in the coming years. China, Canada and Australia are among the countries to be tackled next.

  • "Species on the Move International Conference", University of Tasmania, February 2016. Presentations by three plenary speakers are directly relevant to assisted migration, as follows:

  • "The Role of Decision Science in Assisted Colonisation"

    by Hugh Possingham

    February 2016

    VIDEO (13 minutes)


  • "A Global Overview of Species Range Changes and an Example of Climate Resilience in a Climate Vulnerable Species"

    by Camille Parmesan

    February 2016



  • "How Fast Is Earth Changing?"

    by Will Steffen

    March 2016

    VIDEO (8 minutes)

  • 2017

  • Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems, by Anthony D. Barnosky et al., Science, 10 February 2017.
    EDITOR'S NOTE: excerpted below are the paragraphs that deal with managed relocation and the overall context that is forcing a shift in "conservation paradigms."

    EXCERPTS: The paleobiological approach can further improve species distribution models by incorporating information on trait-environment connections and/or persistent associations of taxa�that is, groups of two or more taxa that co-occur in fossil localities distributed widely through time and space. Current models rely primarily on climatic parameters alone to estimate niche space. Such paleontologically enhanced species distribution models can also be helpful in informing efforts to relocate species into suitable environments, ranging from managed relocation experiments that aim to save threatened species to choosing which trees to plant in urban and suburban landscaping in order to jump-start dispersal in anticipation of future climatic conditions.
         Rather than attempting to hold ecosystems to an idealized conception of the past, as has been the prevailing conservation paradigm until recently, maintaining vibrant ecosystems for the future now requires new approaches that use both historical and novel conservation landscapes, enhance adaptive capacity for ecosystems and organisms, facilitate connectedness, and manage ecosystems for functional integrity rather than focusing entirely on particular species. Scientific break-throughs needed to underpin such a paradigm shift are emerging at the intersection of ecology and paleobiology, revealing (i) which species and ecosystems will need human intervention to persist; (ii) how to foster population connectivity that anticipates rapidly changing climate and land use; (iii) functional attributes that characterize ecosystems through thousands to millions of years, irrespective of the species that are involved; and (iv) the range of compositional and functional variation that ecosystems have exhibited over their long histories.
         Conservation success will also increasingly hinge on choosing among different, sometimes mutually exclusive approaches to best achieve three conceptually distinct goals: maximizing biodiversity, maximizing ecosystem services, and preserving wilderness. These goals vary in applicability depending on whether historical or novel ecosystems are the conservation target. Tradeoffs already occur — for example, managing to maximize certain ecosystem services upon which people depend (such as food production on farm or rangelands) versus maintaining healthy populations of vulnerable species (such as wolves, lions, or elephants). In the future, the choices will be starker, likely involving decisions such as which species are candidates for managed relocation and to which areas, and whether certain areas should be off limits for intensive management, even if it means losing some species that now live there. Developing the capacity to make those choices will require conservation in both historical and novel ecosystems and effective collaboration of scientists, governmental officials, nongovernmental organizations,the legal community, and other stakeholders.
         JOSHUA TREE NATIONAL PARK (as example): Climatically suitable areas may shift northward and upslope, but the slow migration rate of Joshua trees limits their ability to track their suitable climate space, especially because one of their dispersal agents — Shasta ground sloths — is extinct. In this case, the fossil information implies that conserving Joshua Tree National Park in its present ecological state may not be possible because of climate-triggered species turnover, including loss of its namesake species and colonization by currently exotic species. The implication is that conserving Joshua tree ecosystems may require more active management in protected areas outside the national park, acquisition of new lands, and perhaps targeted planting. This landscape-scale management of Joshua trees could nurture the adaptive capacity of the species across its range, even if the national park loses its suitable habitat, while still maintaining the wilderness character of Joshua Tree National Park if wilderness character depends more on the low level of local human impacts than on the presence of Joshua trees.
        Even with ideal corridors, however, species will not all respond in concert as climate changes, a lesson made clear by the fossil record. Some species will move quickly, some slowly, and some not at all, and species will key on different aspects of global change, such as temperature, humidity, or biotic interactions. Effective corridors will maximize the opportunities for such natural adjustments to proceed, even though the end result will be species assemblages almost certainly different than current or historical ones.

  • "In the Sierras, New Approaches to Protecting Forests Under Stress", by Janet Marinelli, Yale Environent 360, 13 February 2017. Click for excerpts.

  • "Helping Forests Migrate", by Richard Heinberg, Resilience, 7 March 2017.
    Author and head of the Post-Carbon Institute, Richard Heinberg, published a lengthy and very readable review article on the assisted migration issue — specifically how it is manifesting in forest conservation practices:
       EXCERPT: "Reading the arguments as they evolved among conservationists over the past decade or two is sobering, frightening, and occasionally heart-rending. One realizes just how much is at stake, how much has already been lost, how much is at risk over the short term, and how much more over the long term. The essential motive of wild lands conservation was and is to keep relatively undisturbed areas away from human interference so that native species can persist in their myriad diversity, and so that evolution can continue to do its slow, transformative work. The fact that many conservationists are now contemplating or actively involved in assisted migration programs should tell us just how dire the climate crisis is."

  • "Seeking International Agreement on What it Means To be 'Native'", March 2017, by James J. Gilroy, Julian D. Avery, and Jule L. Lockwood, Conservation Letters.
    EXCERPT (the entire section head titled) "Nativeness and 'Assisted Migration'": Many species may lack the capacity to shift their ranges in response to environmental change, either due to dispersal limitation or low productivity within their native ranges (Men�ndez et al. 2006). This has prompted calls for conservationists to perform "assisted migration," actively establishing new populations in areas where conditions are predicted to become increasingly suitable (Hoegh-Guldberg et al. 2008). There has been much debate on the practicalities and ethics of this approach (e.g., Mueller & Hellman 2008; McLachlan et al. 2009), but little explicit consideration of how assisted migration fits alongside existing policies related to nonnative species (Schwartz et al. 2012).
         Assisted migration can be targeted towards areas that lie within the former native range of a species, but where populations are extirpated (i.e., "reintroduction"). For example, the translocation of Florida torreya (Torreya taxifolia) to areas 500km north of its current range has been described as a "reintroduction," although it was only present in that area approx. 65 million years ago (McLachlan et al. 2007). In many cases, however, translocation may only be feasible to areas outside the native range of the species. Under our framework, this would result in the establishment of a "nonnative" population, potentially resulting in a conflict with invasive species legislation. On one hand, this could be beneficial in reducing the likelihood of ad hoc and poorly planned independent translocation attempts (McLachlan et al. 2009). On the other hand, if invasive species legislation impedes efforts for assisted migration, this could increase the risk of extinction among severely climate-threatened taxa (Hoegh-Guldberg et al. 2008; McLachlan et al. 2009). This suggests that some legislative flexibility may be necessary in order to deal with particularly acute conservation challenges, although any plans for assisted migration should always be carefully vetted for potential impacts in the new range (Richardson et al. 2009).
  • "Regeneration Dynamics of Coast Redwood, a Sprouting Conifer Species: A Review with Implications for Management and Restoration", April 2017, by Kevin L. O'Hara et al., Forests.
    EXCERPT: ... Restoration strategies in a changing climate should include a broad set of tools, as it is not clear yet how species will adapt to the increase in the temperature. Multiple scenarios need to be considered. The already difficult process of migration of trees to new habitats, restricted to maximum distances of seed dispersal, is further complicated in redwood because the species is reliant on a sprouting reproduction strategy. The data from common garden trials might be used to evaluate the potential for the assisted migration in redwood. It may be possible to shift the range of the species further north, along the coastline of Oregon, where moisture conditions will be suitable for species survival and reproduction. Another strategy may be enrichment planting of drier and warmer provenances to diversify the gene pool of existing redwood stands and increase their resilience to climate change. However, with either assisted dispersal or blending of provenances, active management of redwood forests will be necessary.
  • "Vulnerability of eastern US tree species to climate change", 2017, by Brendan M. Rogers et al., Global Change Biology. Click for excerpts from the "Uncertainties" section on modeling methods. Note: The Duluth Tribune did a story on this paper in its 10 March 2017 issue.

  • "In NE Minnesota, a 'test kitchen' for saving northern forests", May 24, 2017, by Dan Kraker, Minnesota Public Radio News.
    EXCERPTS: "It's just so on the edge," said Lee Frelich, director of the University of Minnesota's Center for Forest Ecology. "And we've already warmed up a fair amount. One or two more degrees of warming would definitely tip the balance away from boreal."
        The only question remaining, said Frelich, is how much boreal forest will Minnesota be able to retain on the colder parts of the landscape.
        In several decades, assuming a "business as usual scenario for carbon dioxide emissions," Frelich expects much of the northern boreal forest will convert to a temperate hardwood forest that's common in much of central and southern Minnesota, dominated by maples, basswood and oaks. But, he said, if projects like the Nature Conservancy's prove successful, it may be possible to preserve remnants of the boreal forests in cold spots like the north facing slopes of hills, or boggy areas where cold air drains, interspersed among more southerly species that migrate northward.
        This effort to preserve "conifer strongholds" in northern Minnesota is an example of a broader climate change adaptation strategy, in which land and wildlife managers try to preserve what are known as climate "refugia," those cold spots on the landscape where threatened species may continue to thrive as the climate changes around them.
        Protecting these climate cold spots, or conifer strongholds, is the flip side of another strategy often called "assisted migration," in which foresters plant southerly species like red and burr oak in northern areas, to help facilitate their transition northward and ensure that the region doesn't lose its forestland. The technique is controversial. Some land managers argue it could lead to unknown, unintended consequences. For example, it could create new invasive species.
        The Nature Conservancy and U.S. Forest Service began experiments three years ago to examine how different species fare farther north. The Minnesota DNR is now looking at planting red oaks near Sawbill Lake on the southeastern edge of the Boundary Waters, said Paul Dubuque, silvaculture program coordinator for the DNR who's advising The Nature Conservancy on its project. To make the forest more resilient to climate change, it's important to diversify the forest as much as possible, Dubuque said. "That has a lot of benefits for not only timber, but forest products, wildlife habitat and biodiversity."
        Crews will be planting conifer seedlings on 30 sites across northeast Minnesota through the end of the month. The Nature Conservancy hopes to plant 400 acres of trees this year, and another 400 next year. The effort will cost about $450,000, with funding coming from the Wildlife Conservation Society. It's a lot of money, said White, the forest ecologist, as he stooped to inspect a recently planted white pine seedling — a tiny beginning to what he hopes will grow into a more resilient future forest. "We just think it's really important to get out in front of these issues," he added. "We don't really have a lot of time to figure it out. So we think the time is now to start adapting how we manage our forest lands."

    SEE ALSO: "Scientists planting 400 acres of Minnesota pines to survive climate change", 23 May 2017, Minneapolis Star Tribune.

    SEE ALSO: "Measuring the Future of Minnesota's Trees Amidst Climate Change", 30 May 2017, University of St. Thomas Newsroom.

    FULL ARTICLE: Sophomore Rachael Heier spent last summer researching how annual climate change may affect our native trees in a zone where winters are projected to be closer to that of current Wisconsin, and summers closer to that of current Kansas. "Many large, broad-leafed trees, pines, oaks, are not able to adapt quickly enough to changing temperatures," Heier said. "It's pretty impactful to see an actual physical effect on these things you see and love as a Minnesota citizen." Heier worked with biology associate professor Simon Emms, connecting with — and funded by a grant from — Great River Greening on the Fish Creek restoration project, which St. Thomas has helped with since 2011. "It provides an opportunity to work on a really important question in conservation biology and restoration ecology: How do we preserve natural areas and the biodiversity they contain in the face of climate change that is altering the physical and biological conditions that those areas experience?" Emms said. "Second, it enables [students] to see how they can participate in meaningful, practical activities that protect, preserve and restore local natural environments — both for the wildlife that lives there and for local communities to enjoy." For Heier, those practical activities centered on assisted colonization, where two types of saplings from the same species of white oak were planted "to see if we would transplant similar species that are adapted to warmer or colder climates," Heier said. Heier and others counted and measured about 830 year-old plantings, which represent the baseline for measurements that will continue for another 10 to 15 years, she said.
        "It was cool to be on the front end and laying down the base groundwork, this really essential part," Heier said. While Heier said she long has been interested in mitigating climate change, working on research like this helped her see the kind of impact smaller-scale projects can have toward bigger results. "It's not the biggest thing but everything does start on a local level. If you can do these projects and make it work, then it could be implemented on a wider scale and have even more impact," she said. "It made me feel better about the problem, no matter how large and insurmountable it is. This made it manageable to know there are physical things we can do about it." "None of us individually is going to be able solve the world's major environmental problems, so the key is to find something positive to contribute at a local or regional scale and recognize that if many others do the same, global change is possible," Emms added. "Rachael was a great research student — she was interested in the project, intelligent, hard-working and thoughtful. Regardless of what she does next, having had a meaningful research experience as an undergraduate will be of great benefit to her."
  • "Divergence of species responses to climate change", 17 May 2017, by Songlin Fei et al., Science Advances.
    EXCERPTS: We analyze abundance data over time for 86 tree species/groups across the eastern United States spanning the last three decades. We show that more tree species have experienced a westward shift (73%) than a poleward shift (62%) in their abundance, a trend that is stronger for saplings than adult trees. The observed shifts are primarily due to the changes of subpopulation abundances in the leading edges and are significantly associated with changes in moisture availability and successional processes. These spatial shifts are associated with species that have similar traits (drought tolerance, wood density, and seed weight) and evolutionary histories (most angiosperms shifted westward and most gymnosperms shifted poleward). Our results indicate that changes in moisture availability have stronger near-term impacts on vegetation dynamics than changes in temperature. The divergent responses to climate change by trait- and phylogenetic- specific groups could lead to changes in composition of forest ecosystems, putting the resilience and sustainability of various forest ecosystems in question
         As expected, we also found evidence of poleward shifts in abundance, which is more prominent in high latitudes where substantial warming has occurred during the study period. Our abundance-based poleward shift rate (11.0 km per decade) is similar to a previous estimated rate (10 km per decade) that is based on leading/trailing edges for forests in the eastern United States. The fact that the longitudinal shift was 1.4 times faster than latitudinal shift suggests that vegetation dynamics are more sensitive to precipitation than to temperature, at least in a near-term time frame, because moisture availability is considered a critical factor in forest dynamics of eastern North America.
        The predominantly northward shift of gymnosperm trees, along with all Populus species and most Betula species, is intriguing. The mechanism for the northward shift could potentially be linked to species pollination methods because we found that most wind-pollinated species (most gymnosperms and some angiosperms) shifted northward while animal-pollinated species (most angiosperms) shifted southward. Similar northward shifts of clades were observed in the New England area during the early Holocene (between 10,000 and 8000 years ago), where Picea was replaced by Pinus, followed by Betula and then Quercus species (37). However, the historical process took place over several thousand years, whereas the observed shift in this study happened in a few decades, suggesting the impacts of recent climate change, along with other nonclimatic factors (for example, land use change and forest management), on vegetation dynamics.
        Note: Associated Press report of the article here.
  • "Quantifying the need and potential of assisted migration", 2017, by M.H. Hallfors, S. Aikio, and L.E. Schulman, Biological Conservation.
    EXCERPTS: Here we present a conceptual framework for identifying and quantifying situations in which predictions indicate that a species could benefit from assisted migration. We translate predicted changes in suitable area into separate metrics for migration need and migration potential on the basis of the amount of lost, remnant, and new area. These metrics can be used as part of decision-making frameworks in determining the most suitable conservation method for a specific species. They also hold potential for coarser screening of multiple species to estimate the proportion of species that could benefit from assisted migration within a given time frame and climate change scenario. Furthermore, the approach can be used to highlight time frames during which assisted migration or, alternatively, other conservation actions are the most beneficial for a certain species.
        A concern that traditional conservation methods may not be enough to safeguard species from decline has led to proposals of new proactive methods, such as actively moving species to new areas in pace with the changing climate. Although rarely implemented to date, this approach has been extensively discussed. It has variously been called assisted migration, assisted colonization, and managed relocation, among others, and also defined in different ways. In the strict sense, however, it is a type of conservation translocation (sensu IUCN, 2012) in which species are moved from their indigenous range to areas where they would be predicted to move as climate changes, were it not for anthropogenic dispersal barriers or lack of time (see Hallfors et al., 2014 for a thorough discussion); here we refer to the method in this sense and call it assisted migration (AM).
         To begin with, it should be noted that wide consensus on the acceptability of AM has not been reached (Hewitt et al., 2011; Maier and Simberloff, 2016; Siipi and Ahteensuu, 2016). Nevertheless, AM has already been conducted for the conifer Torreya taxifolia in the USA (Barlow and Martin, 2004; Marris, 2008) and for two butterfly species in the UK (Willis et al., 2009), and is being considered, e.g., for the butterfly Euphydryas editha quino (Marris, 2008). Hence, it is important to develop best-practice guidelines for the possible future implementation of the method even if their application, in the end, may not turn into mainstream conservation practice. Indeed, several frameworks have been presented for guiding decisions on whether and when a species needs AM, for risk evaluation, and for planning the process if deemed feasible (Hoegh-Guldberg et al., 2008; Richardson et al., 2009; McDonald-Madden et al., 2011; P�rez et al., 2012; Schwartz & Martin, 2013).
         The absence of a recognized method for utilizing the information on range change predictions means that managers wishing to evaluate the appropriateness of AM are left with a recommendation on what tool to use but with no instructions on how to use it. This lack of guidance may result in subjective decisions and thereby inconsistent policy, or even in a status quo where no decisions are made, leading to a high risk of losing biodiversity in a rapidly changing world. A formal and rigorous way of utilizing range change predictions for the specific purpose of AM evaluations and decisions is therefore needed... A species that is not losing suitable habitat does not need to migrate and a species that will not have new climatically suitable area outside its current distribution area will not benefit from migration (with migration we mean the processes of dispersal, colonization, and establishment, which in the case of AM are aided by humans). Hence, vulnerability assessments concentrating on species' sensitivity to climate change are not sufficient to inform decisions regarding AM. Instead, both estimates on climate change exposure and on availability of new suitable area for translocations are necessary when deciding on and planning AM.
  • "Environmental Improvements in the North American Pulp and Paper Industry", 11 June 2017, by Phil Riebel, Printing Impressions [paper industry trade magazine].
    KEY PARA: "Due to climate change, ranges for many tree species in Canada are expected to shift northward over the next 50 years. Because tree species have a slow natural migration rate, it is unlikely that they will be able to keep up with the projected climate shifts and may no longer be suited to their environment. This could reduce forest health and productivity and have related impacts on forest biodiversity. Given that hundreds of thousands of hectares of forest are regenerated annually in Canada, assisted migration of commercial tree species, or the human-assisted movement of plants and seeds to new and more suitable locations, could represent a relatively low-risk and potentially effective approach to introducing a degree of climate change resilience into Canadian forests in the future."
  • "Beech trees native to Scotland after all, scientists discover", 4 July 2017, news report,, re science paper in Journal of Biogeography, DOI: 10.1111/jbi.13053 by M. Jennifer Sjolund et al., (behind a paywall_, "Understanding the legacy of widespread population translocations on the post-glacial genetic structure of the European beech, Fagus sylvatica"
    EXCERPTS: Beech trees should be considered native to Scotland — despite a long-running debate over their national identity, researchers at the University of Stirling and Science and Advice for Scottish Agriculture (SASA) report. The team examined the DNA of more than 800 beech trees at 42 locations across Great Britain and made direct comparisons with trees growing on mainland Europe. The study — funded by the Natural Environment Research Council (NERC) — shows almost all of the beeches growing in Great Britain the researchers tested, are derived from native populations and, as a result, could not have been planted from abroad. Professor Alistair Jump, of the University of Stirling's Centre for Environment, Heritage and Policy, said: "The beech tree has been experiencing an identity crisis in Scotland. Evidence shows that the European beech was mainly confined to the southeast of England after the last Ice Age. However, this tree now occurs throughout Scotland and has been considered 'not native' by many land managers. "This tree can colonise ancient woodland in Scotland, and is sometimes removed because it poses a threat to the persistence of other native species. Our study shows that beech should be considered native throughout Great Britain, including Scotland." Dr Jennifer Sjolund, of SASA, added: "The beech tree has been planted in Scotland in the past but the planting was from native British stock and, although humans have speeded its northward spread, it would have naturally spread up the length of the country regardless. "Our findings have significant implications on how we define native species and how we consider natural processes when deciding what we base woodland management plans on. It points to a need to look again at the identity and distinctiveness of native Scottish forests, which historically haven't featured the beech tree."
  • "Climate Change, Managed Relocation, and the Risk of Intra-Continental Plant Invasions: A Theoretical and Empirical Exploration Relative to the Flora of New England", June 2017, Featured Review, Rhodora, DOI: 10.3119/16-10 by Jesse Bellemare, Bryan Connolly, and Dov F. Sax. Editor's Note: This lengthy paper will not be behind a paywall; here it is linked to a pre-pub pdf. (Online link for this paper via BioOne.) It is excerpted at length here because its data analysis delimited to a particular region enabled conclusions to be drawn that substantially ease the concern re "invasiveness" for moving small-range endemic plant species of the American southeast poleward toward and into New England.
    ABSTRACT. The high rate of anthropogenic climate change projected for coming decades and evidence of low migration ability for many species have led researchers to warn of a looming extinction crisis. This threat is expected to be most acute for small-ranged endemic species, which could see novel climatic conditions develop rapidly across the entirety of their limited geographic ranges. To avoid extinctions, some conservationists have proposed that climate-imperiled species might be candidates for "assisted colonization" or "managed relocation" to new regions, outside their historical ranges. One major concern related to managed relocation is the possibility that some relocated species could later become problematic invasives where they are introduced. In this review, we consider how these emerging conservation challenges might unfold for the flora of New England. A range of evidence suggests that most plant species native to New England might be resilient to immediate extinction risk from climate change, as these species typically have broad geographic ranges and have migrated long distances in response to past climate change. In contrast, regions to the south, particularly hotspots of plant endemism in the southeastern US, harbor numerous small-ranged species whose current climatic niches could rapidly shift beyond their native ranges, leaving them vulnerable to extinction unless they colonize new regions to the north. Consequently, debates surrounding managed relocation in New England are likely to be focused primarily on the ecological risks versus conservation benefits of accepting climate-threatened endemic plant species from the southeastern US, and to hinge on concerns about the invasive potential of these species. To provide an empirically-grounded estimate of invasion risk from the introduction of US native plant species to New England, we reviewed invasive species lists for New England and tallied those species that are native to other parts of the contiguous US (versus other regions and continents). Between four and ten "invasive" or "potentially invasive" plant species reported from New England are from other regions of the contiguous US, depending in part on how issues of native versus exotic genotypes within taxa are resolved. A review of current floristic data from New England shows that these 4 to 10 problematic species are drawn from a larger pool of 374 US native plant species reported as exotic in the region, suggesting that only 1.1 to 2.7% of species appearing spontaneously as adventives in the region are viewed as invasive. In light of this analysis, we suggest that managed relocation is not likely to spawn large numbers of new invasives, and might therefore be judiciously evaluated alongside other conservation options for climate-threatened plant species. We propose a collaborative effort among field botanists, land managers, conservationists, and academics in New England, partnering with botanists in the southeastern US, to initiate fundamental research to experimentally test the viability and ecological effects of climate-threatened endemic plant species from the southeastern US in the New England region.

    EXCERPTS. Rapid climate change may outstrip the migration abilities of many slowly dispersing species, leaving their populations exposed to new climatic conditions that might not support continued survival. This high rate of climate change "velocity" (Loarie et al. 2009; Sandel et al. 2011), likely requiring species to migrate at rates approaching 10 to 80 km per decade to keep up, is predicted to exceed the natural dispersal and migration capacities of many species (Corlett and Westcott 2013; McLachlan et al. 2005). Although numerous species have migrated successfully in response to past episodes of rapid climate change, e.g., during Pleistocene glacial cycles, the high rate of anthropogenic climate change, combined with the widespread fragmentation of the modern landscape by human development, agriculture, and other barriers to natural dispersal, is predicted to trigger a major extinction crisis in coming decades (Thomas et al. 2004; Urban 2015).
          ... Many of these same endemic forest plants are grown in horticulture far to the north of their native ranges, at places like the Garden in the Woods or the Arnold Arboretum in Massachusetts. This suggests that climatically-suitable habitat might already exist far to the north of their small native ranges in the southeastern US, a pattern that is consistent with dispersal rather than climate limitation of these species' geographic distributions in areas poleward of their native ranges (Bellemare and Moeller 2014; Sax et al. 2013).
          Overall, it appears that some plant species, like small-ranged endemics, have exhibited little potential for northward migration in response to past climate warming, even over the thousands of years since the late Pleistocene. Although these endemic species concentrated in the southeastern US would probably have been geographically well-positioned to survive the climatic cooling of another ice age cycle, as occurred repeatedly in the Pleistocene, the current trend toward rapid and long-term climatic warming seems to place many on the "wrong side" of climate history.
          ... It is clear that direct evidence of demographic declines or local extinctions linked to recent environmental change would be the "gold standard" for confirming a species' vulnerability to climate change and for triggering serious discussions of unconventional conservation options, like managed relocation. Although the types of long-term demographic studies that could provide this evidence are lacking for most endemic plant species in the southeastern US, there is some field evidence of problematic trends. For example, the iconic southeastern US endemic Torreya taxifolia Arnott, a conifer native to a small area centered along the Apalachicola River in the Florida panhandle, has declined precipitously in recent decades and might face extinction in the wild, likely due to a combination of novel pathogens and warming climate (Schwartz et al. 2000). Anecdotal reports from field botanists suggest that other temperate forest endemics in the region, like Magnolia ashei Weatherby and M. pyramidata W. Bartram, might also be declining (J. Tobe, Ecological Resource Consultants Inc., pers. comm.). In the well-documented case of T. taxifolia, a private group called the Torreya Guardians has already launched unofficial managed relocation efforts aiming to naturalize the species at sites in the southern Appalachians, where the tree apparently grows more successfully than within its small native range on the coastal plain (Barlow and Martin 2004; but see Schwartz 2004). Clearly further empirical research is needed to directly document population trends in the field, and to experimentally test the performance of endemic species under novel climatic conditions.
          The top concern for most biologists and land managers is the possibility that some species moved to new regions via managed relocation efforts might become problematic invasives (Mueller and Hellmann 2008; Ricciardi and Simberloff 2009)
          ... Despite years of research on invasion biology and exotic species management, it is still very challenging to predict invasion potential in plants, so a scenario where a species translocated for conservation purposes might later become a problematic invasive is almost impossible to rule out entirely, even with experimental screening efforts or trait-based predictions (Lockwood et al. 2013; Mack et al. 2000; Williamson 1996). Citing the "precautionary principle," this has led some biologists to argue against taking any management actions that could inadvertently lead to harmful biological invasions (Ricciardi and Simberloff 2009, but see Sax et al. 2009).
          However, ecological data are emerging to suggest that the types of intra-continental movements proposed in the context of managed relocation might not be as risky as they would first appear (Mueller and Hellmann 2008; Simberloff et al. 2012). In particular, most exotic plants viewed as problematic invasives have been introduced from other continents, not from other parts of the US. In fact, only a small proportion of plant species considered invasive somewhere within the continental US are native to other parts of the US, rather, almost all problematic invasive plants are introductions from other continents (Simberloff et al. 2012).
          ... In terms of invasive plant species in New England, as of Fall 2015, IPANE listed 111 plant taxa as invasive or potentially invasive in the region. Of those, 10 species (9%) are possibly US native plant species, and the remaining 91% are from regions outside the contiguous US (see Table 1 for US natives; IPANE website for full list). Even among the 10 taxa considered US native invaders of New England, several might be excluded on closer examination, either because their native status is in question or because they are invasive in only a limited ecological setting.
          ... Of the US native invasives discussed above for New England, only Robinia pseudoacacia and Cabomba caroliana are considered highly invasive across the region. Humans have widely, and often intentionally, dispersed both species, with invasions likely resulting from repeated introductions. For example, Robinia pseudoacacia was originally introduced from the southern US for its hard, rot-resistant wood (EDDMaps 2015), while C. caroliana is common in the aquarium trade and has been secondarily spread by recreational boating (EDDMaps 2015). Notably, this pattern of widespread, repeated, and unmonitored introduction is probably unlike anything that would be proposed in the context of a planned managed relocation effort, where a target species would likely be introduced in a much more limited and closely-managed fashion to better detect early signs of problematic behavior.
          ... For example, among the four US native plant species we have considered clearly invasive across New England (Table 1), the legumes Amorpha fruticosa and Robinia pseudoacacia might have been excluded in advance due to their ability to symbiotically fix nitrogen and propensity for aggressive clonal spread. Likewise, six of the invasive species in Table 1 are linked to wetlands, a habitat with a history of problematic invasions, and thus likely to trigger intensive critical review prior to any translocation efforts. As such, simple filters based on plant traits and habitat affinity might have precluded intentional release of most of the US native species considered invasive in New England, had similar species been proposed for managed relocation.
          ... Overall, our review of US native plants reported as adventive or invasive in New England suggests that, consistent with other studies (e.g., Mueller and Hellmann 2008, Simberloff et al. 2012), such plant species do not pose a great threat of intra-continental invasion. Most importantly, these findings suggest that the widespread perception that a large proportion of exotic species become problematic invasives when moved to new regions is not consistent with available empirical data, particularly when the species movements occur within continental regions.
          Several hypotheses have been proposed as to why US native plant species are not prone to high rates of invasive behavior beyond their ranges in the US. First, plant species living within a broad geographic area or biome likely have a shared ecological and evolutionary history spanning millions of years, even if they do not occur together across the entire region presently. This suggests some level of co-evolution within ecological communities that might constrain many native species from becoming too successful or invasive in regions near their native ranges (Simberloff et al. 2012). Similarly, within a broad geographic region, the natural enemies that have co-evolved with native plant species (e.g., insect herbivores, pathogens, etc.) might regulate population growth, limiting their potential for invasiveness. In contrast, plant species introduced from other continents often leave behind their natural enemies and can exhibit more rampant population growth than natives carrying a higher load of pests and pathogens (i.e., the Enemy Release Hypothesis; Elton 1958; Mitchell and Power 2003). Further, some plant species from other continents might have evolved in a setting with greater biological diversity (e.g., temperate forests of East Asia) and have been honed more finely by natural selection, providing them with fitness advantages in their introduced range, ones that make them more likely to become problematic invaders (Darwin 1859; Fridley and Sax 2014; Vermeij 2005).
          Finally, within a continental region it is likely that most species prone to high population growth rates and rapid geographic spread have already done so, thousands of years ago (Simberloff et al. 2012). In fact, these types of "ancient invaders" are the common, widespread native plant species that form the post-glacial, Holocene vegetation of New England and other northern areas, having colonized these regions since deglaciation, apparently quite rapidly in some cases (Cain et al. 1998; Clark 1998; Johnson and Webb 1989). To some extent, the post-glacial Holocene period might even be viewed as a long-running natural experiment testing plant species' potential for invasiveness and spread in the eastern US. In contrast to the many native plant species that are already widespread in the northeastern US, it appears that many of the small-ranged endemic species concentrated in the southeastern US are among the species least likely to spread rapidly (Bellemare and Moeller 2014). Overall, these trends suggest that invasion risk from US native species, particularly small-ranged taxa, is probably quite small. On balance, a slight possibility of problematic invasive behavior in the future might be an acceptable risk to consider when weighed against the threat of species extinction and permanent biodiversity loss.
          Finally, one of the core goals of managed relocation would be to maintain species as wild, ecologically and evolutionarily dynamic entities over time. Establishment of translocated populations in natural areas would allow climate-threatened species to maintain ecological interactions with other species in the wild, and possibly evolve and adapt to climate change (Weeks et al. 2011). Although more traditional ex situ options, such as seed banks and preservation in botanic gardens, have certainly played a crucial role in plant conservation efforts worldwide for many decades, such efforts cannot be viewed as a permanent substitute for wild, self-sustaining populations (Oldfield 2009). This is particularly true in the case of species whose native ranges might be compromised by altered climate, as the timescales involved extend over millennia (Ganopolski et al. 2016), and reintroductions to the species' former native ranges might never be feasible.
          Geographic ranges and ecological communities are dynamic. On human timescales, most plant species appear to have relatively static geographic distributions and most ecological communities seem to maintain relatively constant species composition. For the most part, the only plant species we directly perceive as actively expanding their ranges are ecologically-threatening invasive plants with histories of recent introduction and rapid spread. However, as paleoecological and paleontological studies have clearly demonstrated, this stasis and apparent equilibrium among the native, non-invasive flora are illusory once broader timescales are considered (Davis 1983; Jackson et al. 2000; Williams et al. 2004); as Iverson and McKenzie (2013) noted: "range shifts are nothing new." Many temperate plant species have migrated widely across eastern North America during the late Pleistocene and Holocene, and their distributions at the Last Glacial Maximum (LGM; ~20,000 y ago) are likely to have been very different from where they are found today (Huntley and Webb 1989; Jackson et al. 2000; Williams et al. 2004). New England was fully glaciated at the LGM, so our entire flora has been assembled in the recent geologic past from plant species that survived the Pleistocene in other regions (Barrington and Paris 2007; Jackson et al. 2000). Indeed, much of the New England temperate forest flora might be viewed as a subset of the broader species pool present in the unglaciated portions of the eastern US. At the community level, paleoecological evidence clearly suggests that plant species have migrated individualistically in response to past climate dynamics, not as unified communities, with members of present-day communities arriving in the region at different points in time and from different geographic sources (Davis 1976, 1983; Jackson et al. 2000; Webb 1988). Some researchers have even speculated that northern forest plant communities are still not "saturated" with species due to this slow, and potentially ongoing, history of post-glacial colonization (Bellemare and Moeller 2014; Gilbert and Lechowicz 2005).
          Although many of the small-ranged endemic plant species that might be candidates for managed relocation in the future are not currently native to New England, it is probable that many have a shared ecological and evolutionary history with plant species and other organisms that are native to the region. Even today many plant species typical of Northern Hardwood forest in New England, such as Betula alleghaniensis Britt., Clintonia borealis (Ait.) Raf., Mitchella repens L., and Oxalis montana Raf., have ranges extending into the southern Appalachian Mountains where they co-occur in forest communities with a suite of small-ranged endemics unique to the southeastern US, such as Cimicifuga americana Pursh, Clintonia umbellata Michx. Morong, and Diphylleia cymosa Michaux (J. Bellemare, pers. observation). On longer timescales, over the multiple glacial cycles of the Pleistocene, it is probable that the temperate flora and vegetation of the eastern US has been repeatedly disassembled and reorganized, often retreating and comingling in glacial refugia in the southeastern US, then expanding to re-occupy northern areas in warmer interglacial periods, such as during the present Holocene epoch (Davis 1983).
          Is unplanned managed relocation already happening and what might be the genetic consequences? Even as ecologists, conservation biologists, and land managers are debating the merits and risks of managed relocation (Ricciardi and Simberloff 2009; Richardson et al. 2009; Sax et al. 2009; Schwartz et al. 2012; Thomas 2011), it appears that some unplanned, accidental managed relocation might already be taking place via the horticultural trade (Bellemare and Deeg 2015; Van der Veken et al. 2008). For example, many plant species from the southeastern US are already present in the horticultural trade across the eastern US as commonly used landscape plants [e.g., Aesculus parviflora Walter, Fothergilla gardenii L., Hamamelis vernalis Sarg., Hydrangea quercifolia W. Bartram, Isotrema macrophyllum (Lam.) C.F. Reed, Rhododendron vaseyi Gray] or as specialty items from native plant nurseries (e.g., Diphylleia cymosa, Shortia galacifolia Torr. & Gray, various endemic Trillium spp.).
          Furthermore, there are records of numerous southern plant species occasionally escaping from horticulture and naturalizing beyond their native ranges in the north (Gleason and Cronquist 1991; Haines 2011). For example, a recent investigation by Bellemare and Deeg (2015) found Magnolia tripetala (L.) L., an understory tree species from the southeastern and mid-Atlantic US escaping from horticultural settings and naturalizing at multiple sites across Massachusetts, nearly 400 km beyond its native range edge in southern Pennsylvania. Similar observations have been reported for Catalpa speciosa (Warder) Warder ex Engelm., Isotrema macrophylla, and I. tomentosa (Sims) Huber, among others (Burk and Lauermann 1977; Burk 1984; Burk and Zebryck 2001). As such, it appears that a subset of native plants, particularly those with ornamental value, might already have had opportunities to shift their ranges northward via inadvertent human assistance (Bellemare and Deeg 2015; Van der Veken et al. 2008).
          Although these horticultural escapes might provide insight into underlying climatic and biogeographic dynamics (Bellemare and Deeg 2015; Bellemare and Moeller 2014; Sax et al. 2013), this mode of plant migration is potentially problematic from a conservation genetics standpoint. The horticultural plants triggering these naturalizations likely represent a very small sample of the genetic diversity present among populations within these species' native ranges. In some cases, adventive populations appear to trace to single horticultural specimens (e.g., Bellemare and Deeg 2015), likely resulting in severe genetic bottlenecks and the potential for inbreeding depression as these new populations establish and spread. Although this mode of colonization and its impacts on genetic diversity might actually be somewhat analogous to the spread of species via rare long distance dispersal events (e.g., during post-glacial migration; Hewitt 2000; Excoffier et al. 2009), it is probably not the approach that would be chosen if managed relocation efforts were designed and implemented in an intentional way (Weeks et al. 2011). For example, much attention has been focused on the unique elements of genetic diversity often preserved among geographically-isolated refugial populations near species' southern range margins in the Temperate Zone, where species have likely persisted across multiple glacial cycles during the Pleistocene (Hampe and Petit 2005; Hewitt 2000; Keppel et al. 2012; Petit et al. 2003). It seems unlikely that plants in the horticultural trade derive from these distinctive, often marginal or disjunct, populations along southern range edges. If anything, horticultural selections might be biased toward material from northern populations under the assumption that cold hardiness would be increased and, hence, marketability across more of the eastern US. However, these more northern occurrences are likely to be those with reduced genetic diversity due to repeated bottlenecks during post-glacial migration (Hewitt 2000).
          In contrast to the inadvertent constriction of genetic diversity that might occur during the horticultural introduction and trade of a plant species, the field of conservation genetics might recommend much broader and more intentional sampling from across the native range to preserve genetic diversity and account for potential ecotypic differences among populations (Hufford and Mazer 2003; Weeks et al. 2011). Further, considerable thought would need to be devoted to the potential for inbreeding vs. outbreeding depression in newly established populations (Charlesworth and Willis 2009; Galloway and Etterson 2005; Hufford and Mazer 2003; Weeks et al. 2011). While there might be arguments for preserving the genetic structure present among populations within the native range (e.g., via establishing a series of distinctive translocated populations), there might also be value in increasing genetic diversity within translocated populations to enhance the potential for adaptive evolution in response to new environmental conditions and changing climate (Weeks et al. 2011). These issues would need to be considered and resolved on a case-by-case basis as threatened species were selected for managed relocation intervention.
          ... Within the eastern US, most candidates for more intensive conservation interventions, such as managed relocation, will likely come from hotspots of botanical endemism in the southeastern US. Are New England botanists, land managers, and the broader public ready to host new plant species via intentional introductions from elsewhere?

  • "Can 'assisted colonization' help save species in a warming world?" , by Greg Norman, in DW Akademie, June 2017.
    INTERNATIONAL EXAMPLES: News report that examines "assisted colonization" controversy from standpoint of these cases: Swamp Tortoise (Australia), America Bison and lodgepole pine (to Alaska), butterflies (England), Pyrenean desman (rodent in n. Spain).

  • Chris D. Thomas: 'We can take a much more optimistic view of conservation' book review by Richard Lea, Inheritors of the Earth by Chris D. Thomas, in The Guardian, July 2017.
    EXCERPTS: Casting aside this familiar way of thinking about the natural world does present a real problem, Thomas admits, because keeping nature as it was in the recent past is an easy goal to define and agree. "The only problem is that — particularly in the context of rapidly changing climate and land use and all the other things we're doing to the world — it's all very well wishing it, but we're not going to achieve it."
         Instead of focusing on preserving past ecosystems, Thomas says, we should concentrate on preserving biodiversity, so that living things can respond flexibly to future challenges. "Nothing that I'm saying lets us off the hook in terms of maintaining the biodiversity that we currently have, but if we accept that it's a dynamic system rather than a static one — if we are prepared to accept biological gains as much as we regret losses, then we can take a much more optimistic view of conservation," he says.
         As the climate shifts, Thomas argues, we must allow animals and plants to shift as well. In some cases, this means transporting species away from places where they can no longer thrive and giving them a chance to survive elsewhere. This kind of intervention runs counter to rules and regulations designed to prevent invasive species, but Thomas says that while some species can cause trouble for human beings, when you look at other organisms, "most of them don't end up causing much of a problem"...
         "So it seems that the risk of causing a problematic invasive species that would eliminate one of the existing species is lower than the chances of the thing dying out if you don�t move it."...
         The author conjures up a future in which African black rhinos find refuge in Mediterranean shrubland, or butterflies from Provence can survive on grasslands in southern England, a world where wingnut trees, currently threatened in the Caucasian mountains, can flourish in British gardens. As soon as you discard the fiction that life on Earth can return to some prelapsarian idyll, conservationists have much more flexibility to protect species in new places, to form new combinations of habitats.

  • Renewal ecology: Conservation for the Anthropocene (opinion article) - by David M.J.S. Bowman et al., August 2017, Restoration Ecology
    ABRSTRACT: The global scale and rapidity of environmental change is challenging ecologists to reimagine their theoretical principles and management practices. Increasingly, historical ecological conditions are inadequate targets for restoration ecology, geographically circumscribed nature reserves are incapable of protecting all biodiversity, and the precautionary principle applied to management interventions no longer ensures avoidance of ecological harm. In addition, human responses to global environmental changes, such as migration, building of protective infrastructures, and land use change, are having their own negative environmental impacts. We use examples from wildlands, urban, and degraded environments, as well as marine and freshwater ecosystems, to show that human adaptation responses to rapid ecological change can be explicitly designed to benefit biodiversity. This approach, which we call "renewal ecology," is based on acceptance that environmental change will have transformative effects on coupled human and natural systems and recognizes the need to harmonize biodiversity with human infrastructure, for the benefit of both.

    CONCEPT DEFINITION: We propose the concept of renewal ecology as an organizing principle for conservation management in the Anthropocene. This concept formally recognizes that rapid environmental change is unavoidable, necessitating critical planning, and action, but also that human modifications of landscapes for provision of food, fiber, and ecosystem services do not necessarily have to come at the expense of biodiversity. We contend that renewal ecology provides a philosophical license for ecologists to sustain biodiversity in the Anthropocene through innovation, and represents a channel for optimistic conservation action in a time of inevitable environmental change. We define renewal ecology as the science essential for creating and managing ecosystems to maximize both biodiversity and human well-being in the face of rapid environmental change. We intentionally advocate a broad definition of renewal ecology because, like the concept of "biodiversity," it provides flexibility in interpretation (Higgs 2003), and is more likely to contribute to "creating a shared vision and vocabulary" that will bring scientists, practitioners, and politicians "closer to creating landscapes that will sustain human well-being and forecast a more promising future for all species on our shared planet" (Chazdon & Laestadius 2016).

    EXCERPTS USEFUL FOR ASSISTED MIGRATION UNDERSTANDING: By accepting environmental change as inevitable and irrevocable, renewal ecology provides those practicing conservation management greater social license to innovate.
         In a world where the physical underpinnings of ecosystems are changing rapidly, a focus on the past as an ideal standard can be unhelpful in places where it is no longer possible to sustain ecosystems within the range of known historical variability (Kareiva & Fuller 2016). Conservation biology, restoration ecology, and invasion biology have been criticized as "Edenic sciences," given their common objective of returning ecosystems to a past, often idealized, state (Stott 1998; Robbins & Moore 2013). Ecosystems in the Anthropocene may have no historical analog and harbor a range of non-native species, some of which may be threatened within their historic ranges.
         The emergence of such novel ecosystems (Hobbs et al. 2006) confronts the "natural system" archetype as the basis of conservation biology (Hagerman & Satter eld 2014). Kareiva and Fuller (2016), for example, argue that current conservation approaches are inadequately equipped for the challenges of the Anthropocene due to entrenched risk aversion — codified in the "precautionary principle." There is certainly concern about assisting the movement of species in the face of climate change (Ricciardi & Simberloff 2009) and that a focus on novel ecosystems provides an excuse for accepting as inevitable the loss of natural systems (Murcia et al. 2014). Many, but not all, of those resisting ecological interventions acknowledge that conservation science needs to be conducted in the face of rapid climate change. Arguably, urban ecologists have most fully accepted the novel ecosystem concept (Hobbs et al. 2006) and the blurring of boundaries between natural and human-dominated ecosystems, recognizing biodiversity values in settings that have been typically considered severely degraded or otherwise profoundly altered by human activities. Given the enormity of change that all ecosystems are facing, we suggest that a new approach is required for designing and managing biodiverse ecosystems and providing human well-being in the Anthropocene. Such an approach must also minimize the collateral damage of human adaptation and development in an anticipatory, proactive, and collaborative way.

  • Swiss Forests in a Race Against Time - by Balz Rigendinger, 30 August 2017, Swiss Info
    EXCERPTS: The spring of 2017 was too hot and the soil too dry for the flat roots of the spruces in the forests around Zurich. However, the dry and hot weather was certainly a boon for the spruce bark beetle, who likes to make a home underneath the tree's surface. Normally the spruce evicts the beetle by drowning it in resin, but this year there was not enough liquid to do so. Hence, there has been more beetle-infested wood noted in Zurich forests, and in order to prevent further infestation, foresters usually cut down the afflicted trees.
         Rising temperatures not only provide the beetle with more food — they also enable it to breed exponentially. Instead of producing one or two new generations, they can bring a third generation into the world in a single summer. A simple calculation thus shows that the number of beetles in a warm year could amount to 3.2 million, compared with 160,000 in a normal year, or 8,000 in a cold year.
         Though the spruce still dominates lower and medium elevations in Swiss forests, the species is definitely endangered. Swiss forest experts believe that it [spruce] will only be able to survive in a few places in the lowlands, and now they are faced with the question of what comes next. They are currently designing the forest of the future for the next 50 or 100 years, when temperatures in Switzerland will be four degrees hotter.
         What is striking is that it is not the ecological fundamentalists and climate alarmists that are tackling the problem. It is the federal scientists and forest experts, one of whom is Christian Kuchli of the Federal Office for the Environment (FOEN). For the past ten years, he and his colleagues have worked on the "Forest and Climate Change" research project, along with the Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL). The project was initiated and developed by politicians after Hurricane Lothar in 1999 as well as the unusually hot summer of 2003, both of which caused widespread devastation in Swiss forests. Now, the findings of the study have been published in a 400-page book that describes soberly how climate change affects Swiss forests and what Switzerland can do to prevent imminent disaster.
         "The trees we plant today will have to grow in a completely different climate," says Kuchli, who is on the research project's board of directors. With federal meticulousness and within the framework of 40 projects, scientists have evaluated Swiss forests in all their diversity. Slope direction, microclimates and soil condition are all affected by the rising temperatures. By 2080, FOEN expects temperatures to rise by 3.1 to 4.3 degrees in Switzerland.
         In light of this, the office is wondering which kind of trees could possibly be planted once spruce and beech can no longer stand the heat. And if the vegetation zones move up by another 700 metres, what would grow in the lowest lowlands of Switzerland?
         Though Switzerland's most important tree, the spruce, may be a native, its omnipresence is due to the fact that about 100 years ago, it was widely planted for its ability to grow well on worn-out soil. Before that, in the 19th century, then-prevalent oak forests were said to be overused and in bad condition, even though they too were man-made during the colonization by Alemmenic tribes about 1,300 years earlier. The weather-resistant wood was highly valued and its acorns were nutritious food for pigs. "Oaks grow the best ham," farmers used to say in autumn when they drove their pigs into the woods to find fodder.
         The oak tree, resistant to heat, storms, and drought, will see a revival in Switzerland. "It will dominate the forests at lower and medium elevations," Kuchli predicts. "However, we do not yet know how well our native oak will grow in the year 2100. That's why we are looking at regions that already have the climate we are expecting to have." For example, Kuchli recently travelled to France to look at holm oaks. His excursion took him to Mont Ventoux, about 300 kilometres south of Switzerland.
         While global temperatures have risen by 0.8 degrees Celsius since the beginning of industrialization, Switzerland has warmed up by 1.7 degrees due to its continental location.
         There are already quite a few animal species that benefit from milder winters. The deer, for one, breeds well and happily nibbles on silver fir and oaks. "Unfortunately, these are the most important tree species in our fight against climate change," Kuchli says. Will wolves and lynx be able to regulate the deer population? Or would the answer be the Douglas Fir, a giant conifer that copes well with dryness and rarely becomes infested with parasites? The downside is that it is not native to the country.

  • American pika disappears from large area of California's Sierra Nevada mountains - by Tim Stephens, 30 August 2017, University of Santa Cruz News Center
    EXCERPTS: The American pika, a small mammal adapted to high altitudes and cold temperatures, has died out from a 64-square-mile span of habitat in California's northern Sierra Nevada mountains, and the cause appears to be climate change, according to a new study published August 30 in PLOS One. Researchers surveyed pika habitat throughout the north Lake Tahoe area and found that pikas had disappeared from an area that stretches from near Tahoe City to Truckee, more than ten miles away, and includes Mount Pluto. This local extinction is the largest area of pika extinction yet reported for the modern era. "The loss of pikas from this large area of otherwise suitable habitat echoes prehistoric range collapses that happened when temperatures increased after the last ice age," said lead author Joseph Stewart, a Ph.D. candidate at UC Santa Cruz. "This time, however, we're seeing the effects of climate change unfold on a scale of decades as opposed to millennia."... the study forecasts that by 2050 climate change will cause a 97 percent decline in suitable climate conditions for pikas in the Lake Tahoe area.
         The authors note that while management actions such as habitat protection, restoration, or assisted migration may be helpful for some climate-imperiled species, management options for the pika appear to be limited. "Our hope is that simply getting the word out there that climate change is causing iconic wildlife to disappear will get people talking and contribute toward political will to reign in and reverse climate change," Stewart said. "There's still time to prevent the worst impacts of climate change. We need our leaders to take bold action now."

    Editor's note: For a lessening of concern see this 2018 news article reporting on a new study by Connie Millar: "American pikas found to tolerate global warming better than expected". Journal reference: Constance Millar et al. "Distribution, climatic relationships, and status of American pikas (Ochotona princeps) in the Great Basin, USA."

  • Small Pests, Big Problems: The Global Spread of Bark Beetles - by Cheryl Katz, 21 September 2017, YaleEnvironment 360. Editor's note: This is the best background news article I have seen on both the plight of USA conifers and globally.
    TAGLINE: Warming temperatures are fueling the expansion of pine and spruce beetle outbreaks across North America, Europe, and Siberia, ravaging tens of thousands of square miles of woodlands. Scientists warn that some forest ecosystems may never recover.

    EXCERPTS: First, mountain pine beetles devastated lodgepole and ponderosa pine trees across western North America. Then came spruce beetles, which have targeted high-elevation Engelmann spruce, spreading from New Mexico into Colorado and beyond. Altogether, with their advance fueled by climate change, bark beetles have ravaged 85,000 square miles of forest in the western United States — an area the size of Utah — since 2000. Pine beetles also have killed trees across roughly 65,000 square miles of forest in British Columbia, and in the southeastern U.S., they have caused millions of dollars of damage to the timber industry in states such as Alabama and Mississippi.
         The beetles are now advancing up the Atlantic coast, reaching New York's Long Island in 2014 and Connecticut the following year. A new study projects they could begin moving into the twisting pitch pines of New England and the stately red pines of Canada's Maritime provinces by decade's end. Warming winters could push the beetles north into Canada's boreal forest within 60 years, climate scientists say.
         And from Europe to Siberia, bark beetle outbreaks are erupting with increasing frequency in woodlands weakened by rising heat and drought. Switzerland is preparing for the eventual loss of spruce, its most important tree, as warmer weather fans conditions that will make it nearly impossible for all but those high in the Alps to survive. The Czech Republic, Poland, Germany, and Slovakia are all experiencing intense beetle attacks on their Norway spruce. In Siberia, a related spruce beetle has helped another insect pest, the Siberian silk moth, damage more than 1,100 square miles of Siberian fir, pine, and spruce since 2014. That infestation is now spreading northward into historically outbreak-free boreal taiga stands...

  • "Tiny niches and translocations: The challenge of identifying suitable recipient sites for small and immobile species" - by Rob W. Brooker et al., 8 September 2017, Journal of Applied Ecology.
    EXCERPT: Assisted colonisation, one form of species translocation, has been proposed as a tool for helping species to track suitable conditions in a changing climate. There are considerable practical challenges associated with it, including predicting where to place translocated individuals. This problem may be particularly big for small and immobile species, where small-scale microenvironmental conditions de-couple them from environmental conditions as projected in large-scale climate models.

  • Regreening Iceland - 19 September 2017, European Forest Genetic Resources Programme. Editor's note: Because Iceland is so isolated, post-Pleistocene tree-species arrival has been impoverished. Even so, early settlers decimated the native forest. Now, with climate warming, foresters are forced to think more creatively than their continental counterparts. North American dominant conifers (Sitka spruce and Lodgepole Pine) are among those being chosen to "regreen" the island.
    EXCERPTS: ...Some of the afforestation results from the spread of native downy birch (Betula pubescens), which is the only native forest-forming tree species, from remnant stands fenced against grazing sheep. But much has involved non-native species, such as spruces, pines and larch: Picea abies, Picea sitchensis, Pinus sylvestris, Pinus contorta and Larix sibirica, and that's the main cause of controversy. Many conservationists are against the use of non-native tree species for afforestation.
         Native birch, however, "simply isn't productive," explains Brostur Eysteinsson, Director of the Icelandic Forest Service and EUFORGEN National Coordinator in a recently published video. Afforestation, with native and introduced species, has been gathering pace since the 1950s, but as the film shows, many of the trees that were planted originally, are dying. At the time, existing knowledge favoured parent trees based on their original latitude. The climate has changed, with milder winters, which don't suit continental provenances. The focus now for the Icelandic Forest Service is on producing seedlings locally, from carefully selected parents.
         As a result of planting what he calls "genetically well-adapted material," Eysteinsson says that "the forests are growing better than anybody ever thought"...

  • "Earth's oldest trees in climate-induced race up the tree line", in Science Daily, 13 September 2017.
       EXCERPT: Bristlecone pine and limber pine trees in the Great Basin region are like two very gnarled, old men in a slow-motion race up the mountaintop, and climate change is the starting gun, according to a study from the University of California, Davis. The study, published in the journal Global Change Biology, shows that the tree line has been steadily moving upslope over the past 50 years in the Great Basin. The region extends from California's Sierra Nevada, across Nevada to Utah's Uinta Mountains. Its north and south are framed by the Columbia and Colorado rivers' watersheds. The study also found that limber pine is successfully "leapfrogging" over bristlecone pine. They are growing in soils once almost completely dominated by bristlecone pine, and they are moving upslope at a faster rate than the bristlecone pine.
         "We are seeing very little regeneration anywhere in bristlecone ranges except in the tree line and, there, limber pine is taking all the good spots," said the study's corresponding author Brian Smithers, a Ph.D. candidate in the Department of Plant Sciences at UC Davis. "It's jarring because limber pine is a species you normally see further downslope, not at tree line. So it's very odd to see it charging upslope and not see bristlecone charging upslope ahead of limber pine, or at least with it." Continue reading here.

  • Climate change mitigation through adaptation: the effectiveness of forest diversification by novel tree planting regimes, by Anouschka R. Hof et al., Ecosphere , 29 November 2017.
    Editor's note: The term "assisted migration" and its cognates are falling out of favor in academic forestry journals. Rather, adaptation, diversification, and novel tree species / planting regimes are increasingly the terms of use. This signifies widespread acceptance that forest-damaging climate change is underway, to be countered by planting of more warm- or dry-adapted canopy species — both for commercial harvest goals and for ensuring ecosystem services. "Diversity" plantings are also hedges against uncertain climate futures, intended to ensure "resilience" in times of change.
        Overall, "assisted migration" is narrowing to apply to species-centric concerns —, that is, worries that a tree species will severely diminish in range unless assisted in moving poleward (or upslope). This especially applies to threatened or endangered species, such as Florida Torreya in the eastern USA and Giant Sequoia in California. For such species, "assisted migration" will likely receive even more attention as a species-specific ("species rescue") climate adaptation strategy for biodiversity preservation.

  • OPINION: Bad forestry practices compound climate challenge, by Jamie Simpson, The Chronicle Herald (Halifax, Nova Scotia), 3 November 2017.
    EXCERPTS: Forest scientists have known about the 'borealization' of our forests for decades. Forest scientists have also been predicting the negative impacts of climate change on our forest for at least a decade or two. What is disturbing is that our government consistently ignores these serious threats to our forests and continues to support forestry practices that exacerbate the problem. How might we manage our forests if the future (and our children) mattered?
         We'd encourage forest harvesting and silviculture practices that favour trees that are at the northern end of their range (rather than encouraging those at the southern end of their range, as we are doing now). This means less clearcutting and more partial cutting methods. It means adopting thinning practices that favour our southern species and forests with a diversity of tree ages growing together. This is not an impossible thing to accomplish. I've seen it done by progressive foresters on numerous woodlots in the span of a couple of decades.

  • "Tracking lags in historical plant species' shifts in relation to regional climate change", by Jeremy D. Ash, thomas J. Givnish, and Donald M. Waller, Global Change Biology, 2017.
    EXCERPTS: ... Here we explore shifts in the distributions of 78 understory plant species over the past 50 years in Wisconsin and how these relate to shifts in local climatic conditions. We expect climate change to have affected plant distributions given the systematic climate changes that have occurred (WICCI, 2011). We hypothesize that shifts in species' distributions have paralleled shifts in climatic conditions. However, we also appreciate that the ability of species to shift in distribution may be limited by various factors, including limited dispersal (especially in fragmented or heavily modified habitats), competition with other species (in which established plants have an inherent advantage), herbivory (e.g., by white-tailed deer), and other environmental factors.... These comparisons reveal that shifts in species' distributions have generally paralleled shifts in climate, but often fell short. ... Vectors of climate change outpaced those of species' change by an average of 89.7 km, suggesting that over the last 50 years, most plant species have not closely tracked the climatic conditions that supported them 50 years ago.... Overall, the ability of these plant species to keep pace with climate change appears limited and may become more so, particularly if changes in climate are accelerating and barriers to colonization increase. ... Many species may lack the capacity (or opportunities) to disperse adequately to keep up with climate change, particularly in fragmented habitats (Pearson et al., 1998; Verheyen et al., 2004). Species that disperse ballistically, via ants (myrmecochory), and those lacking adaptations for dispersal may have difficulty colonizing new sites, although we do not find evidence here.

  • VIDEO: "Integrating a Scientific Basis for Managed Relocation to Address Societal Concerns of Risk and Benefit", by Mark Schwartz, presentation at "Managed Relocation Under a Changing Climate: An Interdisciplinary Perspective Symposium", at U.Calif Davis, 4 December 2017.
       Editor's Note: Mark Schwartz was an early participant in the assisted migration debate, and he studied Torreya taxifolia as a graduate student. He also was lead author of the ESA working group on "managed relocation" that culminated in a 31-coauthor paper.

    This 17-minute video is a useful introduction, both to the historic roots of the debate and to his own perspective on the importance of decision-making frameworks that include careful study of possible risks of species relocation to the "recipient ecosystem."

    In the first 1.5 minutes of this video, Schwartz provides background on his early research on Torreya taxifolia and summarizes the work (and legality) of Torreya Guardians actions in moving ahead with assisted migration.

    SUMMARY OF ACTION:- Philip Stielstra, a retired Boeing professional who has been volunteering for the Archangel Ancient Tree Archive, recruited parks department staff in 30 communities around Puget Sound (Washington State) to plant more than 300 rooted branchlet clones of some of the biggest Coast Redwoods in California. The website of this ongoing project (first plantings December 2016) is Moving the Giants to Puget Sound. There was no controversy about this project, and there were several supportive print and television news reports. As well, he recruited Plant-for-the-Planet kids in several of the communities to do the actual planting, supervised by parks staff. Seattle Weekly news report on the redwood planting event (with lots of photos): Kid Climate Activists Still Planting Trees, Inspiring Grownups.
        Stielstra is also the first to document Sequoia sempervirens naturalizing in the Puget Sound area. Note: Connie Barlow, founder of Torreya Guardians, later went onsite with Stielstra and VIDEO-documented the multi-aged seedlings that the redwood tree had launched into the surrounding regrowth forest at Hutt Park, Edmonds WA.

    2022 UPDATE: "Moving the Giants" has relaunched as

  • INVASIVE SPECIES ADVISORY COMMITTEE: "Managed Relocation: Reducing the Risk of Biological Invasion" - U.S. Department of the Interior, December 2017 (3 pages plus citations). ISAC Members: Edward E. Clark, Jr. (Wildlife Center of Virginia), Dan Simberloff (University of Tennessee), Mark Schwartz (University of California - Davis), Brent Stewart (Hubbs-SeaWorld Research Institute), and John Peter Thompson (Maryland Nursery and Landscape Association).
    EXCERPTS: ... In order to further Action 4.1.3, a Managed Relocation Task Team was established under the auspices of ISAC. This paper reflects the work of that task team, including internal group discussions, expert consultations, and literature review. The Task Team considered two parallel bodies of science to inform the analysis: a) the species translocation literature (Schwartz and Martin 2013; Seddon 2010), particularly as it relates to changing climates and b) a parallel, more empirically rich and much larger literature on the harmful consequences of invasive species on ecosystems (Mack et al. 2000) and on prediction and management of the risks of invasion (Hulme 2009; Kolar and Lodge 2002; Simberloff 2009; Thuiller et al. 2005). See Annex 1 for examples of managed relocation scenarios, Annex 2 for a list of referenced literature, and additional as citations for further reading.
        The task team offers the following key finding and recommendation to strengthen federal capacities to reduce the risk of biological invasion being facilitated through managed relocation practices....
        At a minimum, the national policy and any supporting policies should:
    A. Limit the use of managed relocation to extraordinary circumstances;
    B. Delineate conditions that constitute legitimate exceptions to E.O. 13571 (e.g., imminent extinction of a keystone species), recognizing that the national need that may supersede the caution imposed by the executive order;...
    Private Landowner Effects on Public Lands - Private land managers have the capacity to a affect public lands by introducing non-native species to their property with little or no ecological justification. These species may spread onto federal lands creating a potential need for land managers to either declare the species an invasive species or of conservation value. The Torreya Guardians began a program to actively spread Torreya taxifolia more than a decade ago (http://www. The group began with an effort to expand this species' range from northern Florida and southern Georgia over 600 km northward to North Carolina. The group has continued the spread of T. taxifolia as far north as Michigan and New Hampshire and west to Oregon with apparently no effort for ecological justification. In all cases the group has endorsed private plantings of this federally listed endangered tree species on private lands in a manner that is ecologically unjustified and risky, though they have not violated any rules or guidelines adopted by any governing body... [Editor's note: Torreya Guardians did not move the species into Oregon; that was done by a private landowner in Oregon several decades before the group was established; the group did accept seeds offered by the Oregon grower in 2016, for planting east of the Mississippi.]

    Advancing Commercial Interests - Natural resource-based industries (especially horticulture, forestry, and aquaculture/commercial fisheries) are engaging in mass relocation of species for economic gains (Benito-Garzon et al. 2013; Dumroese et al. 2015; Fady et al. 2016; Fontaine and Larson 2016; Klenk and Larson 2015; Pedlar et al. 2011; Pedlar et al. 2012; Williams and Dumroese 2013; Winder et al. 2011). When biological invasion results from these translocations, the economic benefits to a relative few may result in substantial, long-term costs to the public. Federal partnership with private land managers are needed to help minimize the risk of managed relocation activities by private sector groups on neighboring public lands and, more broadly, the well-being of Americans.


  • REVIEW PAPER: Managing consequences of climate-driven species redistribution requires integration of ecology, conservation and social science - by Timothy C. Bonebrake et al. (42 coauthors; 22 pages), 2018, Biological Reviews
       ABSTRACT: Climate change is driving a pervasive global redistribution of the planet's species. Species redistribution poses new questions for the study of ecosystems, conservation science and human societies that require a coordinated and integrated approach. Here we review recent progress, key gaps and strategic directions in this nascent research area, emphasising emerging themes in species redistribution biology, the importance of understanding underlying drivers and the need to anticipate novel outcomes of changes in species ranges. We highlight that species redistribution has manifest implications across multiple temporal and spatial scales and from genes to ecosystems....

    ... Understanding range shifts from ecological, physiological, genetic and biogeographical perspectives is essential for informing changing paradigms in conservation science and for designing conservation strategies that incorporate changing population connectivity and advance adaptation to climate change. Species redistributions present challenges for human well-being, environmental management and sustainable development. By synthesising recent approaches, theories and tools, our review establishes an interdisciplinary foundation for the development of future research on species redistribution. Specifically, we demonstrate how ecological, conservation and social research on species redistribution can best be achieved by working across disciplinary boundaries to develop and implement solutions to climate change challenges. Future studies should therefore integrate existing and complementary scientific frameworks while incorporating social science and human-centred approaches. Finally, we emphasise that the best science will not be useful unless more scientists engage with managers, policy makers and the public to develop responsible and socially acceptable options for the global challenges arising from species redistributions.

    EXCERPTS: We believe that 'species redistribution science' has emerged as a field in its own right. However, to date the field has lacked strategic direction and an interdisciplinary consideration of research priorities....Faced with climate change as a novel and substantial threat, a new species-management paradigm has emerged (Stein et al., 2013): to be effective, conservation strategies must account for both present and future needs and must be robust to future climate change. Such strategies will require integration of species redistribution science with consideration of the social and economic consequences (Table 1). Managers have several options for conserving species and ecosystems faced with range shifts: adapt conservation management in current landscapes and seascapes; facilitate natural species movement; manage resources to support species redistribution; and/or move species as a conservation intervention, i.e. managed relocation.... In this section, we do not duplicate former reviews of the explanatory and anticipatory ecology of species redistribution. Our review focuses, instead, on gaps in explanatory and anticipatory ecology that need to be filled in order to predict the impacts of species redistribution on biodiversity and human well-being. To achieve this aim, we examine multiple elements of explanatory ecology, including the physiological and ecological factors underpinning species redistribution, biotic interactions and historical ecology, as well as climate trends and extreme events. We conclude this section with a discussion of the challenges of anticipatory ecology.... Some of the most dramatic impacts of community change are likely to arise through the assembly of novel species combinations following asynchronous range shifts associated with climate change. These predictions are supported by palaeoecological studies that show how novel species interactions resulting from past climatic changes drove profound community-level change. The emergence of novel ecological communities will pose significant conservation and societal challenges, because most management paradigms are insufficient to cope with major reorganisation of ecosystems.... The rate of contemporary climate change, genetic constraints on rapid adaptation and dramatic land cover changes over the past century will challenge 'natural' species redistribution in the Anthropocene and complicate human responses to these changes.... Studies in deep time allow us a glimpse into the outcome of processes similar to those that we are watching in their infancy today....Climate-velocity methods (Burrows et al., 2014) or the analysis of fine-scaled climatic grids (Ashcroft et al., 2012) can be used to identify climate refugia — places where microclimates are decoupled from macroclimatic fluctuations and are thus more stable and less likely to change quickly — as potentially good candidates for future protected areas. Information on future habitat suitability for threatened species (e.g. obtained using SDMs) can be coupled with information on climate refugia to target areas likely to maximise conservation benefits.... Conservation easements, for example, while popular and potentially effective in environmental protection of private land, rarely consider climate change impacts or species redistribution.... Researchers also need to understand what information land-owners, planners and policy makers actually need to aid decision-making, which requires considerable engagement and knowledge exchange.

    ...The primary challenge for practicing MANAGED RELOCATION is identifying ways to overcome any social barriers to relocation. Relocating species for conservation can challenge deeply held values and beliefs about human intervention in nature, and what constitutes appropriate and desirable environmental stewardship.... Issues include cultural nuances, such as the terminology used in management proposals and policy. For example the term 'assisted colonisation', adopted in the guidelines of the International Union for Conservation of Nature (IUCN) for species introductions outside of the known range to prevent extinction, has historical and colonial connotations with the word 'colonisation' that may create barriers to participation. In this case, an alternative, culturally considerate phrase to encourage broader inclusion might be 'managed relocation' (see Schwartz et al., 2012)

    ... Rapidly developing tools and networks in citizen science may enhance large-scale monitoring.... The promptness of decision-making in community-based monitoring and the focus of the decisions at the operational level of species and resource management make community-based monitoring approaches particularly suitable when species are rapidly shifting ranges. Community-based monitoring is also likely to provide information about crucial new interactions between species.... Although long-term monitoring programs provide the essential foundation for tracking and understanding the causes and consequences of species redistributions, they also encounter funding difficulties due to the long time span of funding required and a bias in grant agencies away from studies perceived as simply observational research and towards hypothesis-driven research. Institutional change in funding agencies and an emphasis on prioritising interdisciplinary and long-term projects could lead to important, high-impact climate change research (Green et al., 2017). In the meantime, global change scientists also need to explore multiple options to support long-term and interdisciplinary studies, such as harnessing citizen sciencecitizen science may help to fill the knowledge gap in long-term and spatially extensive studies. Citizen science approaches typically involve recruiting observers to be part of a formal program, a method for recording meaningful data, and a means of making those data accessible and discoverable for later use....interpreting the results of these efforts to tell a story of environmental functioning or change to larger audiences.


    (1) Until recently, species redistribution was seen as something that would happen in the future rather than an immediate issue. However, it is happening now, with serious ecological and societal implications and impacts already being observed.
    (2) The cross-cutting nature of species redistribution calls for the integration of multiple scientific disciplines, from climate science to ecology, palaeoecology, physiology, macroecology, and more. We further suggest that research on contemporary species redistribution needs to span process-based studies, observational networks by both scientists and community members, historical data synthesis and modelling over a variety of scales.
    (3) Species redistribution defies conservation paradigms that focus on restoring systems to a baseline and challenges environmental management strategies, which are often static and based on human-dictated boundaries drawn in the past. Climate-driven species redistribution therefore presents both fundamental philosophical questions and urgent issues relevant to conservation and society.
    (4) For species redistribution research to support development of relevant adaptive strategies and policy decisions adequately, studies need to take an interdisciplinary approach and must recognise and value stakeholders. Involving stakeholders in monitoring and collection of data offers an opportunity to help guide effective adaptation actions across sectors.

    EDITOR'S NOTE ON INDIGENOUS LANGUAGE CONCERNS: Almost all of the authors of the above lengthy Bonebrake et al. review paper are Australian. As with the United States and Canada, Australia is a nation dominated by recent colonizing immigrants from Europe. Hence, criticism of the term "assisted colonisation" as offensive to indigenous peoples. Three of the authors in the Bonebrake et al paper published a short article in 2016, directly on the theme of poor language choices (Lee et al. They wrote, "Arguments against the assisted colonisation terminology include its hegemonic overtones and historical references."

  • Adaptations of white spruce to climate: strong intraspecific differences in cold hardiness linked to survival - by Jaime Sebastian-Azcona et al., 8 January 2018, Ecology and Evolution
    EXCERPT of ABSTRACT: Understanding local adaptation of tree populations to climate allows the development of assisted migration guidelines as a tool for forest managers to address climate change. Here, we study the relationship among climate, a wide range of physiological traits, and field performance of selected white spruce provenances originating from throughout the species range. Tree height, survival, cold hardiness, hydraulic, and wood anatomical traits were measured in a 32-year-old common garden trial, located in the center of the species range... Our results suggest that assisted migration prescriptions may be advantageous under warming climate, but pronounced trade-offs between survival and cold hardiness require a careful consideration of the distances of these transfers.

       EXCERPT of INTRODUCTION: Geographic patterns of local adaptation of forest trees have been studied since the 18th century, and most studies found that local populations were the best fit to a specific environment (Langlet, 1971). This has led forest managers to develop so-called seed zones, where areas of similar conditions were defined, assuming that individuals coming from that area would have superior growth and survival when planted within the same seed zone. More recently, climate change has led to locally adapted populations lagging behind their optimal climate niche, thus challenging the assumption that "local is best" (Aitken, Yeaman, Holliday, Wang, & Curtis-McLane, 2008; Davis & Shaw, 2001).

    Gray and Hamann (2013) found that based on observed climate trends, forest tree species in western North America already lag behind their optimal climate niche by approximately 130�km in latitude. Furthermore, Alberta also experienced a reduction in precipitation in the past 25 years (Mbogga, Hamann, & Wang, 2009), and the trend toward drier conditions may continue during the 21st century (Wang, Hogg, Price, Edwards, & Williamson, 2014). As a consequence, trees may become increasingly maladapted to new climate conditions.
         One way of accommodating changes in climate is the use of seed sources from areas already adapted to warmer temperatures as part of regular reforestation programs. This usually implies selecting seeds from southern areas to be planted in a more northern region (Millar, Stephenson, & Stephens, 2007). Such assisted migration prescriptions depend on identifying well-adapted genotypes from matching climate regions. This can be carried out using provenance trials, in which seed sources collected from different geographic regions and different environments are planted in a common garden where genetic differences between populations may be observed. If promising genotypes can be identified in provenance trials, then these genotypes could be moved and planted where their characteristics match the anticipated climate. Previous work on white spruce provenances in different parts of its distribution suggests that transfers toward the north can increase growth rates (e.g., Gray et al., 2016; Lesser & Parker, 2004; Li, Beaulieu, & Bousquet, 1997; Lu et al., 2014; Rweyongeza, Yang, Dhir, Barnhardt, & Hansen, 2007)....
         In the boreal forest, increased temperatures may have a positive effect on tree growth, as has been observed in some white spruce populations (Danby & Hik, 2007; Lloyd & Fastie, 2002; MacDonald, Szeicz, Claricoates, & Dale, 1998). But this positive effect will only occur with adequate water availability, as the opposite effect was found in drier areas or years, showing that drought can be an important limitation for white spruce development in the future (Barber, Juday, & Finney, 2000; Chen et al., 2017; Danby & Hik, 2007; Jiang, Huang, Stadt, Comeau, & Chen, 2016; Lloyd & Fastie, 2002). Even if precipitation rates are not affected by climate change, increased temperatures will enhance drought stress in plants by increasing transpiration. With higher transpiration, water reserves will deplete faster resulting in a heat-induced drought (Breshears et al., 2005). Moreover, snow reserves will melt earlier, further reducing water availability later in the growing season (Barnett, Adam, & Lettenmaier, 2005). Finding a productive and drought-resistant genotype might be a difficult challenge as trade-offs between growth and heat/drought resistance have been reported in white spruce (Bigras, 2000, 2005). The trade-off between hydraulic safety and efficiency of the xylem was analyzed in detail by Gleason et al. (2016), arriving at the conclusion that although the correlation between both traits is not always clear, the combination of both high efficiency and high resistance is not possible. This trade-off can be partially explained by anatomical features of the tree such as wood density, conduit size, or ratio between photosynthetic and conductive tissue (Gleason et al., 2016; Sperry, Hacke, & Pittermann, 2006).
         Even though frost events are lower in frequency and severity under recent climate warming, extreme cold events may still occur on rare occasions, especially if overall variability in climate increases. A single unexpected frost event can cause great damage to forests if it occurs after the start of the growing season (Gu et al., 2008). Man, Kayahara, Dang, and Rice (2009) also reported severe frost damage in a white spruce stand after a late spring frost. As such frost events that cause dieback and mortality are rare, it remains difficult to assess the risk involved in moving planting stock north, even with data from long-term provenance trials because mature trees may not be as susceptible to frost damage as seedlings and saplings. Generally, differences between provenances in the onset of cold hardiness in fall are greater than in the release of cold hardiness in spring, so a movement in latitude might have a bigger effect in changing susceptibility to early frosts in fall (Aitken & Hannerz, 2001). Cold hardiness heavily relies on the phenology of the onset and release of dormancy, and a trade-off between growth and cold hardiness is usually driven by how long trees extend their growing season in the fall (Howe et al., 2003). The effect of climate change in fall usually gets less attention than other seasons even though fall events can have an important ecological impact (Gallinat, Primack, & Wagner, 2015).
         While growth performance of white spruce provenances has been well studied, there is a lack of understanding of which physiological and anatomic traits are responsible for those genetic population differences. Trade-offs between growth and cold hardiness or drought resistance could pose an additional challenge for forest managers to maintain the productivity and health of our forests under climate change. The research approach of this study was to screen groups of contrasting provenances from a wide variety of climatic source environments for a broad suite of physiological and anatomical traits that are putatively adaptive. To further enhance the probability of finding trade-offs and discover genetic differentiation in adaptive traits, we selected provenances with contrasting combinations of growth and survival in a common garden field trial. The specific goals were to (1) quantify genetic population differentiation among provenances from across the entire range of the species for a wide selection of hydraulic, anatomical, and cold hardiness traits, (2) detect possible relationships among resistance to climate (cold and drought), tree growth, and survival, and (3) analyze how these traits are related to the climate of origin of the provenances. The results of this range-wide experiment could point to key traits for climate adaptation that could serve as a reference for more geographically limited studies with higher sample densities to support regional assisted migration prescriptions.

  • REVIEW PAPER: "Movers and Stayers: Novel Assemblages in Changing Environments" - by Richard J. Hobbs et al., February 2018, Trends in Ecology and Evolution
    EXCERPTS: "... With global change, particularly climate change, any particular place at any given time will have species that are staying put for the time being, and other species that are either invading or vacating. These phenomena are not new, but current and future environmental changes may be unprecedented in rate, magnitude, and comprehensiveness and in the levels and variety of human interventions. Much has been written about changes in species distributions in response to current and future climate change and other environmental changes and the human role in engineering change through transport of species outside their normal ranges. This deliberate transport includes transport of potentially invasive species and assisted migration of species at risk." FIGURES:

  • Up in Smoke: Trees are dying at unprecedented rates. Can we rethink conservation before it's too late? - by Eric Holthaus, 8 March 2018, Grist
    But some forests simply aren't going to be able to handle the next few decades on their own. A recent study used computer models to test the inherently changing point of view. Researchers looked at a forest ecosystem in a remote part of British Columbia that's susceptible to fires and insect outbreaks. They found that artificially boosting tree diversity increased the forest's capacity for regrowth by up to 40 percent. It's an example of what forest ecologists call "assisted migration," introducing novel species that are expected to do well in the years ahead.
         In Minnesota, conservationists aren't just modeling it with computers. They're actually doing it. At the southern edge of the boreal forest, spruce, fir, birch, and aspen dominate — but their days are likely numbered as warm, dry summers become increasingly commonplace. Researchers at the University of Minnesota-Duluth partnered with the Nature Conservancy to plant 100,000 seedlings of native species more representative of the forests of Minnesota�s future — oak, pine, and basswood — on 500 acres of public lands. While they've grown in the region before, those species are still relatively rare, so the researchers want to study how the trees fare in years to come.
  • Northern protected areas will become important refuges for biodiversity tracking suitable climates - by Dominique Bertreaux et al., 15 March 2018, Nature.

    Editor's note: Although assisted migration is not mentioned in this Canadian report, the implications for species in protected areas seriously lagging in tracking shifts in climate zones is a major conclusion. Hence, the authors' suggestions for effecting shifts in "conservation paradigms" would, of course, imply boosting assisted migration efforts.

    EXCERPT: We are aware that species will not necessarily fully track their new climatic conditions, as several factors can impede or delay immigration of species in protected areas of Quebec. First, dispersal rates could be 1.5 to 3.0 km/yr for birds and 0.1 to 0.5 km/yr for amphibians and plants, respectively. However, the velocity of shift for the 5C isotherm is projected to be about 2km/yr in Quebec during this century. Insufficient dispersal capacities of species will thus delay immigration in response to climate change. In addition, natural and anthropogenic habitat fragmentation can further impede dispersal rates of organisms by reducing connectivity between suitable patches. For example, the St. Lawrence River which divides southern Quebec from east to west, the urbanized area of Montreal, and the fragmented agro-forested habitats of Southern Quebec all represent major barriers to species dispersal. Substantial lags between climate change and resulting immigration were shown for butterflies in Great Britain, forest-understory plants in U.S.A., trees in western North America, and birds in North America and France. Second, competition with presently established species can strongly limit colonization by newcomers. For example, persistence of long-lived conifers in the boreal biome could delay the northward expansion of deciduous trees, which could in turn delay the expansion of birds associated with mature deciduous stands. More generally, we ignored many variables other than climate in defining future habitat suitability of species, therefore our predictions for future suitable habitat are sometimes overly optimistic. Colonization requires sequential successes in the dispersal, establishment, and survival of individuals on new suitable sites as well as growth and persistence of populations via continued reproduction. Immigration of species is delayed if any of these steps is hampered. As a consequence, our results are not meant to offer quantitative assessment of local changes in biodiversity within a specific time frame, but only to provide the best-available indication of the strong pressure that climate change will impose on biodiversity.
  • OVERVIEW ARTICLE: Information Underload: Ecological Complexity, Incomplete Knowledge, and Data Deficits Create Challenges for the Assisted Migration of Forest Trees - by Andrew Park and Carolyn Talbot, April 2018, BioScience.

    Editor's note: This is a superb review article for understanding differences in assisted migration concerns and considerations in forestry v. conservation biology (endangered species). It also explains the importance of (necessarily) missing or uncertain information in Species Distribution Models (SDMs) used for projecting climate-caused shifts in species ranges. Examples include using current ranges as if these represent "fundamental niches" v. smaller "realized niches" — especially for species with slower forms of seed dispersal or blocked by insurmountable geographic barriers. A major topic is that, while climate may be moving seed zones poleward, climate extremes have grown larger — thus subjecting species to episodes of colder temperature, more extended droughts, and magnified year-to-year fluctuations in phenological expression. The importance of choosing correct microsites within the projected range shift is also a central concern, as is the intractable problem of choosing locales in which the climate regime can support seedling establishment but also favorable conditions for continued growth and seed production several or many decades beyond that time.

    EXCERPTS: Forest managers are caught in a vice between the need to make current decisions and the fact that the consequences of those decisions will be realized in a distant and uncertain future. Although this has always been the case, climate change exacerbates uncertainties and imposes decisions that may carry greater risks than in the past. To these risks are added the challenge of translating a flood of research across multiple disciplines into management actions. From this review, we believe a number of important lessons emerge for those considering assisted migration (AM) as a preemptive strategy for coping with climate change.... In this article, we review recent research that informs the complexity of AM decisions. Local microenvironment, herbivory, and intraspecific interactions frequently outweigh climate in determining species establishment and survival. Species adopt several strategies to cope with drought, heat, and cold, but translocated genetic material can display cryptic maladaptation when challenged by extreme, out-of-range weather events. Phenology, photoperiod, and climate are related in complex, often provenance-specific ways. We discuss the implications of our findings for forestry AM and make recommendations for incorporating these insights into future research and AM practice.
         Whereas conservation AM emphasizes species rescue, forestry AM is proposed as a tool to ensure that adapted seed varieties continue to contribute to productive and healthy commercial forests (Pedlar et al. 2012, Williams MI and Dumrose 2013). Three scales of forestry AM are defined on the basis of short- to long-distance movements of genetic material: assisted population migration (APM) of seed sources within the current species range, assisted range expansion (ARE) to areas just beyond current range limits, and assisted species migration (ASM) far beyond current range boundaries (Williams and Dumroese 2013, Messinger et al. 2015, SilviFuture 2017). APM is already incorporated into forest management policy in some jurisdictions. Several Canadian provinces have modified their seed-transfer guidelines (rules governing the geographical sources of locally planted seedlings) in anticipation of moderate climate warming (Pedlar et al. 2011).
  • Indiana's Future Forests: A Report from the Indiana Climate Change Impacts Assessment - by Purdue University Agricultural Extension Service, May 2018.

    Editor's note: - Agriculture Extension forestry materials like this one just published for the state of Indiana demonstrate how noncontroversial the issue of moving trees poleward has become. "Assisted migration" is a term I have not seen in these kinds of reports — and wisely so. By 2018, the term "assisted migration" is relevant only for rare species that conservation biologists are concerned about: Can they disperse on their own fast and far enough to adapt to ongoing climate change? But for common trees, and especially those valued for forest products or other human uses, the idea of planting new species from southward states during reforestation or urban forestry operations sparks no controversy. Here is an example of a public-friendly report of what to expect and what tree species to plant for conditions expected in the 2050s. Concluding paragraphs exemplify the shift to noncontroversial ways of phrasing human involvement in moving trees poleward:

    ... Indiana's future forests will be shaped by a mix of forces including climate, CO2, air pollution, invasive plant species, pests, pathogens and management decisions. The many interactions among these factors are still being untangled. Currently, researchers estimate how habitat suitability for a particular type of tree will change by assuming that the range of climates in that tree's current range defines its future potential habitat. However, it is not clear whether seedlings have the same relationship with climate as mature trees, and even if they do, it is unknown how fast seeds or seedlings of the species will migrate naturally or be intentionally brought to newly suitable areas. This makes it difficult to predict how quickly Indiana�s forest composition might change.
         ... As Indiana's upland forests continue to drift toward dominance by more moisture-loving species (like maples and tulip trees), they become more susceptible to growing-season droughts, suggesting forest productivity and carbon storage could decline. As precipitation increases in winter and spring, flood-intolerant species are likely to diminish in low-lying areas. Some shifts in the makeup of the forest are likely to occur gradually as new species arrive and survive in the new climate while some existing species fail to regenerate. Other shifts may occur rapidly, as more extreme droughts or floods kill ill-adapted species or milder winters lead to new pest or pathogen outbreaks.
         Shifts in the makeup and growth of Indiana's forests will have consequences for our wildlife and economy. Under the changing conditions expected this century, proactive management decisions are necessary to improve the sustainability and resilience of the state's forests.
  • Biological responses to the press and pulse of climate trends and extreme events - by R.M.B. Harris and 20 Australian co-authors, July 2018, Nature Climate Change.

    Editor's note: - While "assisted migration" and "assisted colonization" are together mentioned only 3 times in this 7-page paper, foundational paper (which focuses on abrupt ecosystem failures in Australia), the necessity for these new management practices for ecosystem climate adaptation is transparent. Most important is that the causes of ecosystem collapses (largely unpredictable in timing, but not in general) have two interacting forces: (1) the "press" of ongoing climate change and (2) the "pulse" of extreme weather events (including narrowing time blocks between extreme events).

    EXCERPTS: The interacting effects of climate presses and pulses suggest that management approaches will need to adapt in the future. Many interventions involve practices that remain controversial and for which there are few policy guidelines. Assisted colonizations, for example, or the translocation of warm-adapted genotypes, are not widely accepted practices. The feasibility of other actions may be limited by economic costs, difficulties in accessing remote locations, or the spatial extent of the event. Management interventions will increasingly need to be decided on quickly and without full understanding of the ecological and evolutionary consequences. Focused consideration and planning, cross-disciplinary dialogues and the involvement of management practitioners and policymakers are all needed for successful mitigation strategies. The development of these strategies will require a considered debate about what natural values we desire, what a 'natural', 'pristine', or novel system is, and when active intervention is socially acceptable. The risk of non-intervention may outweigh the risk of intervention more often in the future.
        Climatic presses and pulses are already causing complex and catastrophic responses, leading to population collapse, loss of relictual communities and shifts into novel ecosystems. Such extreme responses call for greater policy and philosophical fluidity in conservation management, greater capacity and appetite for interventions, and detailed documentation of the consequences of interventions.
  • Proactive conservation and restoration of botanical diversity in the Anthropocene's 'rambunctious garden' - by Jens Christian Svenning, 3 July 2018, American Journal of Botany.
    EXCERPTS: ... In the words of environmental writer Emma Marris (2011), "We must temper our romantic notion of untrammeled wilderness and find room next to it for the more nuanced notion of a global, half-wild rambunctious garden, tended by us. Rambunctious gardening is proactive and optimistic; it creates more and more nature as it goes, rather than just building walls around the nature we have left." With this essay, I point to some areas where research can contribute to proactive conservation and restoration of botanical diversity in the Anthropocene. I note that I here use restoration in its future-oriented sense (Choi, 2007) — with a focus on establishing ecosystems that are sustainable in current and future environments and accepting moving, somewhat unpredictable endpoints....
         Some of the key issues to address include (1) improving our understanding of the characteristics and dynamics of plant diversity and vegetation functioning under strong climate change and in novel climates, (2) effective use of assisted migration to minimize dispersal limitation (Gallagher et al., 2015), (3) handling and reducing time lags in the build-up of functional communities and even individuals (e.g., time needed for development of mature or senescent trees), (4) the role of non-natives in the assembly of diverse plant communities in a changed climate, as well as the role of these novel occurrences in to safeguarding plant species at risk from climate change in their native area, (5) maximizing delays in climate-driven extinction, in integration with the adaptive approaches 2-4.
         A third point that I want to emphasize is the need for developing the botanical foundations for rewilding, here defined as ecological restoration to promote self-regulating, biodiverse ecosystems. I see rewilding as a highly important idea for developing proactive approaches to not just safeguard, but also promote biodiversity in the Anthropocene. Our diversity of plants and other organisms has evolved in wide expanses of nature, but a large proportion of species have experienced strong human-driven reductions in available habitat, i.e., comparing habitat availability at evolutionary time scales to the present.... Rewilding, with its active design toward self-management, clearly is central here and also contributes to social wishes and needs for self-willed nature. Approaches involving facilitation of spontaneous social activities with biodiversity benefits could also contribute...
  • Climate Change Is Killing the Cedars of Lebanon - by Ann Barnard, 18 July 2018, New York Times.

  • The Once and Future Northern Forests - by Stephanie Mills, 27 July 2018, Nature Change
    ... One forest type not to bet on in Northern Michigan's coming climate regime will be boreal: quaking aspen paper birch, jack pine, and black spruce will, per the Assessment, lose their competitive advantage of cold adaptation. More southerly species, like American basswood, black cherry, and white oak may gain ground, but overall many of our common tree species may decline. Sustaining or restoring the historic Northwoods character of white and red pine, mixed hardwood forests may just be possible....
         ... "All of us have had to come to grips with the losing battle," said Handler. "When you have this Platonic ideal of the old growth forest, you're setting yourself up for heartache. If you can loosen that a little bit it can be empowering, freeing to realize that we still have a lot of action we can take to conserve and manage our forests so that they can be healthy and vibrant."....
         No one in Handler's position can be a doomsayer: He's as rational and constructive as public servants come. Projections, prospects, and personal preferences converge in his own back yard, though. There he is experimenting with more southerly trees: "I brought up some catalpa and hickory from my parents' home in Iowa," he said. There, too he shows his "soft spot" from hemlock, which he admires because "it can stay shaded for so long and grow so slowly." Despite its being one of the Northwoods species in peril, he has planted a few, with some exclosures and a trusty dog to protect them from browsing deer.
  • Tackling Climate Change - PR Newswire Press Release, 15 August 2018, Markets Insider.
    EXCERPTS: ... Genome BC [private company] put out a call for research projects which can help us understand climate change impacts and promote the development of adaptation and mitigation solutions using genomics. Six projects were funded under this round of the Sector Innovation Program. This program often positions project teams for larger, national funding competitions. And, one of these projects builds on past Genome BC-funded work on the mountain pine beetle but is looking at another, related tiny terror — the spruce beetle.
        Drs. Dezene Huber of the University of Northern British Columbia (UNBC) and Ward Strong from the BC Ministry of Forests, Lands, Natural Resource Operations & Rural Development (MFLNRORD) have a plan to mitigate damage in the context of a shifting climate. With a team that includes colleagues from the University of British Columbia (UBC) and the Canadian Forest Service, they are studying genetic functions to identify traits for breeding a more pest-resistant spruce forest in the future. The team is also building on their past experience with mountain pine beetle genomics by sequencing and assembling the full spruce beetle with the objective of better understanding how beetle populations differ across the landscape.
         In addition to the spruce beetle project, the following were also awarded funding:
  • Epigenetic adaptations of plants to climate change (Greg Henry, Loren Rieseberg: UBC)
  • Testing the conceptual foundations of assisted migration for species facing climate change (Amy Angert, Loren Rieseberg: UBC)
  • "Assisted Migration", 2018, prepared for USDA Forest Service Climate Change Resource Center

    EXCERPTS: Evidence suggests that species have responded individually during historic periods of dramatic climate change through geographic migrations to and from unique glacial refugia. Recent research has demonstrated that many tree species are already undergoing distribution shifts in response to climate change, with different studies highlighting species that are moving poleward and higher in elevation, or moving east-west to track changes in moisture availability. Despite the complexities of forecasting species range shifts into the future, the underlying challenge still remains that many species will face extinction or local extirpation if they do not acclimate, adapt via natural selection, or migrate to new suitable habitats as conditions change.

       EXCERPTS cont: Given the observed and projected rates of change, there is a substantial risk that some species will be unable to migrate quickly enough to track change. Natural migration over long distances requires several generations, and this process is slow because trees require several years to get to reproduction age, and regeneration opportunities may be limited for a variety of reasons. Recent estimates indicate that post-glacial migration rates for many tree species were 100 to 500 meters per year. Recent rates of change for particular locations in the US have been even more dramatic, with rates of change from 1,000 to 10,000 meters per year for large areas of the Midwest, Great Plains, and Southeast, as well as isolated locations in the western US. These distances are a function of climate change rates ("climate velocity") and spatial climatic variation due to topography.
         For species with very specific habitat needs or ranges limited by physical barriers, such as fragmentation or geographic features, this may mean that the entire species could be at risk of extinction or extirpation due to climate change....

    ... Studies involving reciprocal transplants of different species along large gradients have demonstrated the potential for assisted migration to benefit tree species and local populations. For example transplant studies of white spruce in Quebec showed that physiological traits such as photosynthetic rate and stomatal conductance were relatively plastic between populations and suggested that southern seed sources might be used in northern locations to increase growth and productivity without sacrificing seedling survival. Promising results have been demonstrated for species with more restricted ranges as well. Trials with whitebark pine demonstrated that seeds can be successfully germinated and grown large distances (800 km, 500 miles) to the north of the current species range boundary — seed sources from Oregon and Washington performed well in locations in northwestern British Columbia . These studies, and others, have demonstrated that assisted migration is a reasonable option to help populations and species occupy areas of projected suitable habitat under climate change. Furthermore, assisted migration doesn't necessarily need to be implemented as a widespread action to be successful. Even if small founder populations of individuals can survive beyond existing ranges, they may contribute genetic diversity associated with warmer climates to native populations such that the native populations might have a better chance to adapt through natural selection....
         Within the USDA Forest Service, Regional Geneticists have recommended a "no regrets" approach to considering assisted migration and seed transfer as a climate adaptation strategy in the 2012 report "Genetic Resource Management and Climate Change: Genetic Options for Adapting National Forests to Climate Change."...
         This USDA report links to: "Adaptive Silviculture for Climate Change.

  • Conservationists give assisted migration a second look - by Maya L. Kapoor, 20 August 2018, High Country News.
    EXCERPTS: ... Mary Williams, an ecologist who has researched assisted migration as a climate adaptation strategy, cautioned against the "extreme" movement of plants. She recommended instead that seeds be taken from the warmer parts of a plant's existing range, to be grown in cooler parts of its range. Then, when those cooler areas warmed, the plants would already be adapted to the new conditions.
         Because a species' resilience comes from its genetic diversity, spreading the clones or seeds of too few plants could also doom an assisted migration project. Connie Millar, a senior scientist with the U.S. Forest Service who studies how mountain ecosystems are responding to climate change, recommends mixing the gene pools of the trees used for assisted migration projects by collecting seeds and clones from different locations. "Then, natural selection 50 years in the future can sort it out, and we don�t have to predict (survivors), which we're very bad at doing," she said.
         Agencies in the U.S. have toyed with the idea of assisted migration, but no projects are currently in the works. To make tree transplants work, federal agencies would have to find the money for the prolonged follow-up work needed to keep them alive: artificial watering, fertilizer feedings, protective fencing to keep out hungry deer. "Just like in a garden, when you transplant, there's usually transplant shock," Millar said. "It takes a while for roots to get down. ... It's not like they're happy all of a sudden." Similar constraints would limit animal introductions. In many cases, for agencies, shifting species would also require new regulations, such as those that govern post-wildfire replanting.
         The biggest unknown about assisted migration may come down to human behavior: Without knowing how much fossil fuel people will keep burning, researchers can't say for sure how much the climate will change, or where a particular organism�s optimal neighborhood will be in the year 2100.
  • "Past and future global transformation of terrestrial ecosystems under climate change" - Connor Nolan and 41 coauthors, 31 August 2018, Science.

    EXCERPTS: ...Pervasive ecosystem transformations occurred in response to warming and associated climatic changes during the last glacial-to-interglacial transition, which was comparable in magnitude to warming projected for the next century under high-emission scenarios. We reviewed 594 published paleoecological records to examine compositional and structural changes in terrestrial vegetation since the last glacial period and to project the magnitudes of ecosystem transformations under alternative future emission scenarios. Our results indicate that terrestrial ecosystems are highly sensitive to temperature change and suggest that, without major reductions in greenhouse gas emissions to the atmosphere, terrestrial ecosystems worldwide are at risk of major transformation, with accompanying disruption of ecosystem services and impacts on biodiversity....
         Beyond observations of recent and ongoing change, models indicate ecosystem transformation under climate projections for the 21st century. These include dynamic global vegetation models (3, 17), species distribution models (18), and comparison of the multivariate climate distance between biomes with that between modern and future climates (19). However, the capacity for assessing the magnitudes of ecosystem transformation under future climate scenarios is limited by the difficulty of evaluating model performance against empirical records, particularly when projected climate states are novel (19, 20).
         Paleoecological records of past ecological responses to climate change provide an independent means for gauging the sensitivity of ecosystems to climate change. High-precision time-series studies indicate that local and regional ecosystems can shift rapidly, within years to decades, under abrupt climate change (21-23), but sites with such detailed chronologies are scarce. In this study, we used published reports to compile a global network of radiocarbon-dated paleoecological records of terrestrial vegetation com- position and structure since the Last Glacial Maximum (LGM), 21,000 years before the present (yr B.P.) (24). Most postglacial warming happened 16,000 to 10,000 yr B.P., although it commenced earlier in parts of the Southern Hemisphere (25, 26). Global warming between the LGM and the early Holocene (10,000 yr B.P.) was on the order of 4 to 7 degrees C, with more warming over land than oceans (26, 27). These estimates are roughly comparable to the magnitude of warming that Earth is projected to undergo in the next 100 to 150 years if GHG emissions are not reduced substantially (28). The magnitudes of changes in vegetation composition and structure since the last glacial period (LGP) provide an index of the magnitude of ecosystem change that may be expected under warming of similar magnitude in the coming century (29). Although the rate of projected future global warming is at least an order of magnitude greater than that of the last glacial-to-interglacial transition (26), a glacial-to-modern comparison provides a conservative estimate of the extent of ecological transformation to which the planet will be committed under future climate scenarios....
         ...Europe and eastern North America experienced unusually large temperature changes since the LGM, owing to depressed temperatures near the large ice sheets, and these regions show substantial compositional and structural changes since the LGP. However, results from other parts of the globe indicate that widespread ecosystem changes were driven by much smaller temperature changes (fig. S3). ...
         Under the RCP 8.5 scenario [business as usual, IPCC], the rate of warming will be on the order of 65 times as high as the average warming during the last deglaciation (26). Furthermore, the warming between the LGP and the Holocene occurred within the range of previous glacial and interglacial temperatures, whereas projected future changes will exceed those experienced over the past 2 million years (26). Although many ecological responses (e.g., species migration, colonization, and succession) will likely lag behind climate changes, ecosystem transformations will often be accelerated by disturbance and mortality events, land use, and invasive species (7�15)....
         We therefore conclude that terrestrial vegetation over the entire planet is at substantial risk of major compositional and structural changes in the absence of markedly reduced GHG emissions. Much of this change could occur during the 21st century, especially where vegetation disturbance is accelerated or amplified by human impacts (7). Many emerging ecosystems will be novel in composition, structure, and function (42), and many will be ephemeral under sustained climate change; equilibrium states may not be attained until the 22nd century or beyond. Compositional transformation will affect biodiversity via disintegration and reorganization of communities, replacement of dominant or keystone species, pass-through effects on higher trophic levels, and ripple effects on species interactions (16, 43)....

  • Amplifying plant disease risk through assisted migration - by Simler et al., Conservation Letters, September 2018.
    ABSTRACT: Translocation of species, populations, or genotypes beyond their historic ranges (i.e., assisted migration, AM) is an oft-debated climate adaptation strategy. Well-intentioned AM actions could alter disease dynamics for target species and recipient sites, resulting in unanticipated detrimental economic and ecological impacts. Although disease risks are occasionally mentioned in AM debates, current regulations or best practices that reduce or mitigate these complex risks are generally lacking in North America. We use the "Disease Triangle", a foundational framework in pathology, to illustrate pathways through which AM may impact disease emergence, to identify knowledge gaps, and to suggest best practices to reduce disease risks. We highlight empirical examples in which altering pathogen distributions, host communities, and environment have historically resulted in costly and ecologically damaging diseases in plants. Although guidelines to reduce disease risks in AM are generally lacking, policies governing endangered species, invasive species, and disease management can provide starting points for a more comprehensive policy. We use examples from the United States to identify key strengths and weaknesses that can inform regulations to reduce disease risks associated with AM. We argue that consideration of disease motivates policy development that incorporates improved risk assessments, agency coordination, and accountability mechanisms.

    EXCERPTS: ... Direct seeding can reduce the risk of introducing non-native pathogens, compared to planting seedlings, though seeds may also carry some pathogens (Anderson et al., 2004).... Sanitation provides a means of reducing those risks, yet it is important for managers wishing to proceed with AM to understand the limitations of current practices. Given the imperfect baseline knowledge of microbial communities, the prevalence of non-native pathogens in greenhouse and native environments, and limited adoption of sterilization practices, risk management should include actions to reduce hitchhiker-related risks, acknowledge incorporating important unknowns, and develop explicit contingency plans into AM decision-making tools (Schwartz & Martin, 2013).... There are currently no policies in the United States requiring evaluation of risks, arbitrating among competing risks (i.e., extinction vs. invasion vs. disease release), characterizing the conditions under which AM should proceed, or clarifying responsibilities in the event of unintended disease emergence. Here, using the United States as an example, we draw on existing regulations for managing threatened species, invasive species, and disease as examples for developing better regulation of the disease risks associated with AM (Table 3).... Endangered species laws and policies, however, do not provide guidance on how to weigh species extinction risks against the potential adverse implications to recipient ecosystems through translocation. These laws also do not apply to private individuals moving plant species obtained through legal means (Shirey & Lamberti, 2010), further complicating AM management and making culpability difficult to assess. As such, it does not appear that existing implementation of conservation laws or policies adequately addresses the trade-offs in using AM, especially considering disease risks.... Despite extensive policies directed at managing invasive species, it is argued that most states tend to over-regulate potential agricultural pest species while neglecting species that do not directly impact crop species (McCubbins et al., 2013). Regulatory variation among states makes the system only as strong as the weakest state (Brasier, 2008).... Following recent introductions of ecologically damaging invasive plant pathogens in the United States, voluntary nursery certification programs and sanitation best practices have been developed to help growers reduce the occurrence of potentially harmful plant pathogens in the materials they produce (Parke & Gr�nwald, 2012). Though these programs are voluntary, these guidelines can provide a helpful starting place for mandatory regulations on plant materials used AM-focused plantings, to reduce introductions of non-native pathogens.... Existing environmental regulations and policies in the United States only partially address disease risks in AM (Table 3). We propose that a more complete policy provides for enhanced risk assessment, accountability, and coordination in managing these risks inherent in AM activities. ... Thus, we recommend AM policy move beyond single-objective assessments (i.e., assessment of target species benefit) toward integrated system-wide risk assessment.... Diseases have caused significant economic losses (Anderson et al., 2004) that may portend AM-induced disease impacts. In developing policy to reduce AM risks, we think that incentivized or mandatory nursery sanitation approaches, creating early detection protocols, and designing emergency response plans should rise to the top as priorities that currently do not uniformly guide other translocations (e.g., restoration). Policy should also clarify the authority for AM decisions and specify how culpability is determined and damages are assessed. State-level invasive species policies provide a starting point; however, enforcement will be key to deterring unauthorized translocations.

    LAST PARA: We recognize that AM and the abandonment of historical baselines as conservation objectives creates unsettled ethical, legal, and practical concerns for managers and conservation practitioners (Camacho, 2010). These should motivate, not deter, development of proactive comprehensive policy, given disease risks outlined here. We suggest that current fragmentation (and occasional competition) in policies governing AM should make federal agencies reticent to participate until such comprehensive policy exists. Without a cohesive policy that spans jurisdictions and agencies, the default "policy" may simply include programs that discourage private industry from engaging in unregulated AM. The costs of inaction, resulting in some level of species extinction, may ultimately outweigh disease risks associated with AM. This will be a social choice, informed by scientific knowledge. Making that choice responsibly requires evaluation of important trade-offs via risk assessment procedures that incorporate the multiple mechanisims contributing to disease and a coordinated set of best practices. Without these, AM remains a conservation strategy driven by best intentions but with potentially detrimental outcomes.

  • National Climate Assessment, chapter 7, "Ecosystems, Ecosystem Services, Biodiversity - U.S government, 23 November 2018. Editor's note: "Assisted migration" (not managed relocation) is the topic of one paragraph (below).
    ... More active approaches like assisted migration, whereby species are actively moved to more suitable habitats, and genetic rescue, where genetic diversity is introduced to improve fitness in small populations, [212] may be considered for species that have limited natural ability to move or that face extreme barriers to movement due to habitat fragmentation and development (Ch. 5: Land Changes, "State of the Sector" and KM 2). [124] For any assisted migration, there could be unforeseen and unwanted consequences. Developing policies to analyze and manage the potential consequences of assisted migration would not guarantee successful outcomes, but is likely to minimize unintended consequences. [213, 214]
        Editor's note: Footnote 213 goes to Schwartz et al 2012; footnote 214 goes to Invasive Species Advisory Committee 2017.
  • What risks matter? Public views about assisted migration and other climate-adaptive reforestation strategies, by Guillaume Peterson St-Laurent et al., Climatic Change, 5 November 2018.

    EDITOR'S NOTE: While this paper presents results of public values (via interviews) solely within British Columbia, the introduction and citations offer excellent background and key citations on the whole public values literature that has accumulated re the debate about "assisted migration", especially within the forestry context. Key image:

    EXCERPT: ... The observed differences in public views about the two AM strategies being considered by BC's government are notable. On the one hand, the high proportion of respondents who supported AM within natural range suggests that a large majority of BC's public is willing to see AM implemented in BC forests, as long as it abides by species' historical ranges. On the other hand, lower levels of support for AM outside of natural range indicate that the movement of species to other regions represents a contentious element that is, in the eyes of the public, somewhat comparable to the use of exotic species or GMOs. The relative lack of distinction between AM outside of natural range and long-range intercontinental species introductions observed here is consistent with previous research that identifies this issue as a barrier to public consensus in the assisted migration debate (Hewitt et al. 2011).
         In part, public perceptions of risk of AM outside of natural range are also consistent with expert assessments that similarly note increased ecological risks with spatial distance (Mueller and Hellmann 2008). Many of the risks associated with AM outside of natural range do not necessarily apply to AM within natural range (e.g., no chance of creating exotic invasive species; Hewitt et al. 2011). On the other hand, other experts argue that limiting AM to within range movements risks failing to adapt to expected future climates (Pedlar et al. 2012; Winder et al. 2011). Despite relatively low levels of support for AM outside of native range, this strategy was supported in principle by more than half of respondents. However, the majority (69%) believe that more research is needed before AM outside of natural range can be implemented (Fig. 3), thereby confirming the general sense that current uncertainties make its acceptance extremely challenging. The possibility that uncertainties can be reduced through further research (Aitken and Whitlock 2013; Vitt et al. 2010) opens the door to a conceivable decline in public opposition, if and when conclusions demonstrate that the benefits of AM outside of natural range outweigh the risks.


  • Can We Help Our Forests Prepare for Climate Change? - by Madeline Ostrander, December 2018, Sierra Magazine.

    Editor's Summary: This article focuses on the research and questions happening at Acadia National Park as to whether, when, and which more southerly tree species should be given assisted migration into the park. That this lengthy article appears in the national magazine of the Sierra Club and that the author goes onsite to a national park wrestling with the assisted migration question means that, finally, this climate adaptation practice may go mainstream. Notably, the author distinguishes between the early focus on single species needing help moving poleward and the new focus on a land management agency wanting to ensure that a forest canopy remains. Joshua Tree and Sequoia Kings Canyon national parks have previously been the epicenter of national park resistance to assisted migration of climate-injured tree species. But those two parks are brand-named for trees; hence they are the last places to be willing to let go of their famous trees and wish them well northward.

       EXCERPTS: ... But according to multiple projections on the likely impacts of climate change here, many of these trees could dwindle or die off in a matter of decades, leaving the park vulnerable to invasive weeds and bereft of important species that provide habitat to wildlife.... Lifting a species from its current range and dropping it into an entirely new and unfamiliar ecosystem — a process known as assisted migration — is unorthodox and controversial.... Often, scientists discuss assisted migration as a means of saving a particular plant or animal that might no longer be able to live in its historic range — like the American pika, endemic to high-alpine areas of the American West, and the giant sequoia of the Sierra Nevada. In Acadia, park scientists are concerned not just with what species might disappear from the park but also with what might arrive to take their place. They are thinking about what kinds of trees the park will need in order to keep its ecosystems healthy in 50 or even 100 years.

    ... ACADIA'S INTEREST in assisted migration began a few years ago, when new research emerged that made it clear that the park's forests could be headed for serious trouble. Since 2007, the U.S. Forest Service has published a set of models and maps called the Climate Change Tree Atlas, an effort to predict what trees might be able to thrive in which locations as local and regional climate conditions change. Five years ago, Fisichelli — then employed at the National Park Service's Climate Change Response Program in Fort Collins, Colorado — applied those predictions to more than 100 parks, including Acadia.
         The results were sobering. Acadia's most important and common tree, red spruce, would lose about half its living space in the park. Eight other forest tree species native to Acadia, including northern white cedar and balsam fir, would also forfeit substantial portions of their ranges. Four native trees — tamarack, white and black spruce, and balsam poplar — would probably be extinct within the park by the end of the 21st century.

       In the scientific community, there has been much discussion but few field tests of assisted migration, especially relocations over large distances. Sally Aitken, a plant geneticist at the University of British Columbia, has planted whitebark pine — a tree of the Rockies and the Mountain West that is now threatened by a disease called blister rust — in a remote location in the northern part of the province, far above its normal range. A group of grassroots activists stirred controversy a decade ago when they moved endangered Florida torreya trees to locations in North Carolina and as far away as Ohio.
         The Park Service is not the only federal agency considering whether it may be necessary to relocate tree species. The Forest Service has launched trials of assisted migration for commercially valuable tree species at study sites in five regions. But the Park Service, an agency long focused on lofty conservation goals, has especially cautious standards for what species should be planted inside national parks.
         As the Park Service wrestles with the vast crisis of climate change, some within the agency question their role: Should they be taking a more active hand in deciding what nature or wilderness will look like decades from now? Or should they let chance, weather, and random seed dispersal determine what grows in their forests?

         Fisichelli hasn't drawn any hard conclusions yet. "Change is really messy, and it's not always pretty," he says in a measured, professorial tone. "Maybe a park is the place to provide the time and space to those changes and for nature to self-sort . . . or maybe this is the place to try to make those transitions more graceful. Those are the discussions to have." ...
         If there is a major tree die-off, an Acadian forest could fill with a weedy, fast-reproducing shrub like barberry that could choke out plants that are better for forest health and produce more food and shade for wildlife. "OK," Miller remembers thinking, "assisted migration may not be so bad."
         ... Staring at this plot, it's easy to see the challenges of assisted migration. To plant seeds and seedlings is a game of chance and weather — one that becomes chancier as the climate becomes stranger and more volatile. It's hard to know what will survive and what will disappear. Which trees should humans strive to help, and which should we leave to their own devices?
         "That question isn't for me to answer," Fisichelli insists. "It's a question that needs to happen among a larger group, but in society as well." While there are no answers yet, Miller-Rushing says that a decision on assisted migration in Acadia isn't far off....

  • NEWS: Protecting monarch butterflies' winter home could mean moving hundreds of trees - by Giorgia Guglielmi, January 2019, Nature
    ... Forest geneticist Cuauhtemoc Saenz-Romero at the Michoacan University of Saint Nicholas of Hidalgo (UMSNH) in Morelia, Mexico, has been relocating oyamel firs (Abies religiosa) in the Monarch Butterfly Biosphere Reserve, about 100 kilometres northwest of Mexico City, for the past 3 years. A study reporting the results of the experiment is currently under review at a scientific journal. For nearly two decades, the idea of 'assisted migration' — moving species to new areas to rescue them from rising temperatures — has stirred controversy among ecologists. Opponents worry that species introduced into other regions could spread so much that they threaten organisms already living there. But in the case of the oyamel fir trees, some scientists think the risk is worth it. "This is an example of a good experiment," says Sally Aitken, a forest ecologist at the University of British Columbia in Vancouver, Canada....
         ... Saenz-Romero thought that shifting fir seedlings higher up the mountains — where temperatures are cooler — could help to preserve the monarch's winter habitat. A 2017 analysis suggested that his team would have to move seedlings upwards by about 350 metres for the plants to keep up with climate change. In fact, the researchers were able to shift more than 750 seedlings up a mountainside by up to 400 metres, as long as they planted the young trees under the shade of neighbouring bushes. This protected the seedlings from sunlight and extreme temperatures, says Arnulfo Blanco-Garcia, a forest ecologist at UMSNH, and a study co-author....

  • Experimental test of assisted migration for conservation of locally range-restricted plants in Alberta, Canada - by Yuzhuo Wang et al., January 2019, Global Ecology and Conservation

       ABSTRACT: Given projected rates of climate change, species with limited dispersal may be unable to migrate at the pace necessary to maintain their current climate niches. This could lead to increased risk of extirpation or extinction, especially for locally range-restricted species within fragmented landscapes. Assisted migration has been suggested as a proactive conservation tool to mitigate these risks. We tested assisted migration for Liatris ligulistylis and Houstonia longifolia, two perennial forbs considered 'vulnerable' and 'imperilled', respectively, in Alberta, Canada, where they are at their northern and western range limits. Both mature plants and seeds were translocated to replicate sites at four geographic locations along a north-south gradient representing the current ranges of the species (central) and areas south (warmer) and north (cooler) of their current range. L. ligulistylis adult plants thrived approx. 500 km north of the species current range with survival, growth, and flowering similar to or exceeding performance in the current range, the influence of soil was also tested by comparing the performance of transplanted mature plants in soil from the source location versus the translocation (recipient) site. Plants planted into soil from the source location had increased flower bud production at all sites. Seedling establishment was significantly higher at sites north of the current range, but much lower in the southern locations.

    These results suggest that L. ligulistylis is in climate disequilibrium, potentially due to migration lags, and that it might be vulnerable to near-future climate vulnerability. For H. longifolia, the influence of flower morph type and location were tested. Only 8 out 130 translocated adult plants survived, five with thrum flowers and three with pin flowers; no seedling establishment was observed in the first growing season, which experienced drier than normal conditions. Among the eight adult plants, seven survived in the central location and one in the north demonstrating specific habitat requirements and conditions that may make this species difficult for translocation and establishment. Overall, locally rare and range-restricted plants with limited dispersal demonstrate climate sensitivity to current conditions and potential for assisted migration, yet species-by-species testing is needed to understand vulnerability and efficacy of this approach.

  • Climate Change Threatens Our Forests: Minnesota's landscape could radically change in coming decades - by Mark Boswell, 3 February 2019 Minneapolis Star Tribune

       ABSTRACT: For years, Minnesota climate and forest scientists have suspected that the state's tree cover would creep northward as Earth's climate warmed, and the prairies that predominate in the southwest of the state would take over what was previously a mix of fields, deciduous woods and pine forests. It wouldn't happen overnight, but the shift is already underway — prompting concern that Minnesota's signature forests might be lost altogether.

    ... Summer climates will, in effect, shift south-southwest by 100 to 300 miles, depending on the scenario, Lee Frelich said. "So Voyageurs National Park could [become] St. Cloud or northwestern Iowa." The climate is likely to change too fast for plant species to migrate to their new locations, Ryan Toot said. "We'll probably need to use assisted migration," which would mean moving and replacing the plants and trees that can't survive the new climate...."

    Editor's note: 9 September 2019 the Minnesota Daily featured a University of Minnesota experimental site, Cutfoot Experimental Forests at the trailing edge of the red pine's range in Minnesota. "Assisted migration" is mentioned in the article, but it is really about ensuring a viable forest canopy, hence "ecological replacement." What makes it worthy of mention here is that this may be the first test of using a dominant western USA tree as a replacement for eastern USA trees facing a drying climate. The tree is Ponderosa Pine. It's eastern-most range is a disjunct population in South Dakota Black Hills, from which seeds were taken for this Minnesota experiment. "This is the first, if not the largest of its kind in the country," Brian Palik said. Research explores strategies for how forests can adapt to climate change.

  • "Shifting the conservation paradigm: a synthesis of options for renovating nature under climate change" - by Suzanne Prober et al. (all 5 authors are Australian), February 2019, Ecological Monographs

    EXCERPTS: Changes in Earth's climate are accelerating, prompting increasing calls to ensure that investments in ecological restoration and nature conservation accommodate such changes. To acknowledge this need, we propose the term "ecological renovation" to describe ecological management and nature conservation actions that actively allow for environmental change. To evaluate and progress the development of ecological renovation and related intervention options in a climate change context, we reviewed the literature and established a typology of options that have been proposed.... We note that "functional introductions" reflect a form of assisted colonization (also termed assisted dispersal, managed relocation, or translocation). While assisted colonization is often viewed as a last resort conservation option for at-risk, often iconic taxa (see 8D; Oliver et al. 2012, Schwartz and Martin 2013), assisted colonization measures that aim to replace ecosystem functions are often considered more socially acceptable (Prober et al. 2012, Dumroese et al. 2015). Indeed, functional introductions of non-local populations or species were some of the most commonly recommended options in our sample. First preference may be given to introducing better adapted provenances or engineered variants of the declining functional species (Prober et al. 2015), variously known as "within-species assisted migration," "assisted gene flow," or "genetic translocation" (Sgro et al. 2011, Aitken and Whitlock 2013, Dumroese et al. 2015, Fady et al. 2016). This approach includes a shift from the widely accepted "local is best" paradigm for sourcing germplasm for plantings, to mixed-provenancing strategies that aim to mix local genotypes with non-local genotypes with greater physiological tolerances to future climates (Prober et al. 2015). Such interventions are yet to be proven and need to be undertaken within appropriate genetic risk frameworks (Aitken and Whitlock 2013, Prober et al. 2015, Fady et al. 2016).

  • Saving the Florida Torreya - by Dan Chapman, 22 April 2019, U.S. Fish & Wildlife Service publication.

       EXCERPTS: ... Connie Barlow doubts torreya will survive in Florida in a warming climate. She's the founder of Torreya Guardians dedicated to saving the tree by planting its seeds in the wild, particularly in cooler northern climes where torreya supposedly once thrived. "It is still limited to a spot where it would've survived during the coldest time, 15,000-18,000 years ago, but it hasn't found a way to move back north," said Barlow, a science writer who founded the activist group 15 years ago. "If you put the seeds back in Torreya State Park they'll just produce little saplings and die."
         Vivian Negron-Ortiz, a Fish and Wildlife botanist, says the Service has no official policy on the assisted migration of endangered species. "We have to look at all alternatives to have the species in situ [in its original habitat] conserved and protected," said Negron-Ortiz. "Assisted migration could be an alternative given climate change and if there are no other options. But we have to have a plan in place first. It will probably take a lot of resources and a suite of partners to save the torreya."
         ... Connie Barlow says she has a cure for torreya — move them far enough north to escape Fusarium and a steadily warming climate. The torreya "is in deep trouble in its historic native range, so let's give it a chance to establish in cooler realms," Barlow wrote 15 years ago. Her thinking hasn't changed. "'Assisted migration' may be the only stay against extinction." ...

  • Can Human Help Trees Outrun Climate Change? - by Moises Velasquez-Manoff, 25 April 2019 New York Times


    An April 25 New York Times article features climate adaptation projects in forests of northeastern USA — including assisted migration of native tree species (or populations) northward. Projects include reforestation efforts of city watershed forests in Rhode Island that have been devastated by insect pests moving up from the south. Also featured are two forestry projects in Minnesota. One climate adaptation project is on private land. The other is in the Chippewa National Forest.

    Assisted migration northward of plants supportive of an insect endangered in Michigan (Karner Blue Butterfly) is reported, too.

    The article begins with the FORESTRY projects:

    EXCERPT: ... Foresters in Rhode Island and elsewhere have launched ambitious experiments to test how people can help forests adapt, something that might take decades to occur naturally. One controversial idea, known as assisted migration, involves deliberately moving trees northward. But trees can live centuries, and environments are changing so fast in some places that species planted today may be ill-suited to conditions in 50 years, let alone 100. No one knows the best way to make forests more resilient to climatic upheaval. These great uncertainties can prompt "analysis paralysis," said Maria Janowiak, deputy director of the Forest Service's Northern Institute of Applied Climate Science, or N.I.A.C.S. But, she added, "We can't keep waiting until we know everything."
    The article ends with the implication that life forms regulated by the Endangered Species Act are receiving far less climate adaptation assistance than do the common, unregulated species of trees:
    EXCERPT: ... Jason McLachlan, an ecologist at the University of Notre Dame, once spurned the idea of assisted migration, but his views have evolved as the current predicament has sunk in. He concedes Dr. Ricciardi's point about the unknowable risks of moving things around, but counters that doing nothing is also "extremely risky." His broader critique is that classic conservation science risks failure today because it assumes the world is static — and if the world ever was static, it clearly isn't anymore. Consider the Endangered Species Act, he said, a bedrock of modern conservation. It aims to return species to their original habitat. But what if they're now ill-suited to those areas? To deal with the coming upheavals, our very concept of nature and the meaning of conservation needs to become more fluid, Mr. McLachlan said. "We don't have a philosophy of conservation that's consistent with the changes that are afoot." END OF ARTICLE.

  • "Six Reasons National Parks Need Saving and Not Just Celebrating" - by Leta Dickenson, 26 April 2019, Grist
    EXCERPT: ... National parks have long served as a haven for plants and animals, but now, climate change is causing mass migrations. Vegetation is shifting distribution, with many alpine plants moving up in elevation to find cool relief from warming temperatures. However, long-living plants are limited by their slower life cycles, and plants like the Joshua tree have nowhere to go. Literally. Joshua trees are predicted to lose up to 90 percent of their range by the end of the century. One potential solution for smaller, more portable species is assisted migration: the manual relocation of animals or plants to habitats that might be a better fit for the species' requirements. Bull trout in Glacier National Park successfully underwent assisted migration to a higher-elevation lake where the water was cooler and there were no invasive fish with which to compete. However, it's easier to move fish than giant sequoias....

  • "Shifting science: Looking at Grand Canyon's next 100 years" - by Erin Ford, 7 May 2019, Grand Canyon News
    EXCERPT: ... Pete Beier said they now use a course filter approach to preserve about 30 percent of all the different vegetation arrangements, especially those that are rare. With climate change at the forefront, that method will no longer work. Because of that, Beier went on to develop the idea of conserving the stage, which means conserving geophysical settings that support a wide diversity of life.
         Of all those geophysical settings, Beier describes Grand Canyon as one of the best. "If I was going to assemble a place that has great diversity of geophysical settings, close proximity and small and large incidences, possibilities for species to make short distance movements to favorable settings, I couldn't do better than Grand Canyon," he said.
         That makes it a target for proponents of assisted migration — taking species from one location and transplanting them into another as climate change renders the habitat they once called home unsurvivable for them. "That comes with challenges," he said. "Which of these climate refugees are we going to accept and how are we going to manage them?"

  • "An Assessment of the Vulnerability of Illinois' Rarest Plant Species to Climate Change" - by Brenda Molano-Flores et al., May 2019, Castanea
    INTRODUCTION EXCERPT: ... By the end of the century, Illinois summer temperatures are predicted to be analogous to Texas, while precipitation patterns are less predictable (Hayhoe et al. 2010). These predicted conditions will create new biotic and abiotic stresses for most of Illinois' rare plants. The ultimate goal of this work is to make species vulnerability scores and their relative contributing causes available to land managers, policy makers, and researchers, to inform efforts to protect, conserve, and study Illinois' rare plants.... We applied the NatureServe's CCVI tool to all 331 plant species on the 2011 T & E list for Illinois (excluding the one lichen; Mankowski 2010, IESPB 2011).

    RESULTS EXCERPT: Barriers to migration are a leading factor to vulnerability, where 97% of listed species will be limited by anthropogenic barriers and 24% by natural barriers.... Two factors did not show a significant association with the CCVI scores: dependence on other species to generate habitat and dependence on other species for propagule dispersal.

    DISCUSSION EXCERPTS: The very reason that most Illinois plants are rare, habitat loss, will also be the largest driver of the T & E flora's inability to respond to changes in climate. On a positive note, Illinois does not need to worry about sea level rising as a climate change vulnerability concern, compared to most coastal states. However, in Illinois, minimal topographic variation will increase the exposure of its rare plant species to climate change. Anacker et al. (2013) noted that places with topographical homogeneity will experience climate change sooner because plants cannot simply move up or down in elevation. For many Illinois species, latitudinal migration will be the only way to cope with predicted climate change. Due to these landscape limitations, assisted migration might be the only way to overcome dispersal barriers.... Difficult decisions must be made to prioritize efforts and resources in the face of imminent global climate change if we are to maximize the number of species that will persist into the not-so-distant future.... For Illinois, conservation efforts should prioritize species that have a substantial portion of their known populations in Illinois, as well as endemic and nearly endemic species. Vulnerable species for which Illinois is part of the northern (poleward) or central portion of the range should receive a higher priority.... Species for which Illinois constitutes the eastern or western portion of their ranges should be the next priority. Finally, it may be prudent to put the lowest priority on species for which Illinois is the southernmost portion of their range (especially taxa with extensive northerly ranges and populations beyond Illinois), at least in terms of in situ conservation work, because it is most likely that conditions will become unsuitable for these species in Illinois. We acknowledge that this is contrary to the traditional thinking, that sinks the most attention and resources into species that are the most vulnerable in a given community and/or region.
         The great majority of Illinois rare species will be vulnerable to predicted climate change. Although we are not the first state to conduct plant CCVI assessments (e.g., California [Anacker et al. 2013], Colorado [CNHP 2015], Michigan [Lee et al. 2011], Pennsylvania [Furedi et al. 2011], New Jersey [Ring et al. 2013], and West Virginia [Byers and Norris 2011]), we believe that we are the first state that has reviewed every listed plant in their flora. This has given us a unique ability to assess climate change systematically; we have ranked the most imperiled species and the most important factors threatening them. Rapid accelerating climate change is part of the new normal, and identifying the most vulnerable species and aggressively tackling their conservation should be a priority for government agencies. However, we also acknowledge that prioritizing and then conserving vulnerable species will not be an easy task due to the large number of rare plants, addition of new species that are not currently listed, funding limitations, and the complexity in considering climate vulnerability alongside other threats. Nevertheless, we find that the NatureServe's Climate Change Vulnerability Index has been a useful tool for identifying conspicuous differences among species.

  • "Public trust and knowledge in the context of emerging climate-adaptive forestry policies" - by Guillame Peterson St-Laurent et al., 15 July 2019, Journal of Environmental Management
    ABSTRACT EXCERPT: ... We use the example of genomics-based assisted migration (within and outside of natural range) in British Columbia's (BC) forests to examine the relative roles of and interactions between trust in different forestry actors and knowledge of forestry in shaping public support for this new and potentially controversial management alternative. Our results, based on an online survey, reveal low public trust in governments and the forest industry combined with low levels of public knowledge about forest management. We find that individuals who are more trusting of decision-makers and other important forestry actors hold higher levels of support for assisted migration. Higher levels of forestry knowledge are linked with support for assisted migration within native range, whereas no knowledge effect is observed for assisted migration outside of native range. We discuss the implications of these observations and provide recommendations to more fully engage with the challenges of low levels of trust and knowledge in this context.

    Editor's note: In the Sci-Hub full text link, the term "assisted migration" appears 60 times in this article.

  • Climate breakdown is pushing Brazil's iconic Araucaria tree to extinction - by Beth Daly, 10 September 2019, The Conversation
    Editor's note: While assisted migration is not mentioned in this review of a new research paper, the projected shrinkage of range is mapped and the need for refugia within the current range emphasized. However, this paragraph speaks of the role indigenous peoples played in helping this valuable food source tree (Araucaria angustifolia) expand to the fullness of the range that climate offered it prior to the arrival of colonizers.
    And for truly long-term conservation planning which looks beyond the next decades, or even the coming centuries, we could learn a lesson or two from the past. Evidence suggests that indigenous people helped Araucaria forests expand beyond their natural boundaries around 1,000 years ago, although how and to what extent isn't yet clear. Investigating how millennia of climate change and centuries of human actions combined to shape the present-day Araucaria forests may reveal ways of helping them survive the grave challenges of the coming decades.

    "Collect, Save, Adapt: Making and Unmaking Ex Situ Worlds" - by Anna-Katharina Laboissiere, September 2019, Cultural Studies Review

    EXCERPTS: ... Combining a collection of the world and the salvation of endangered species is not, however, the only or last mandate of ex situ conservation. In what might seem a return of acclimatisation and landscape-moulding ambitions of colonial botany, recent years have seen the emergence in the scientific literature of proposals for assisted migration, the 'translocation of a species to favourable habitat beyond their native range to protect them from human induced threats, such as climate change'20 ... As of now, most of these proposals for assisted migration are still highly speculative, with notable exceptions such as the citizen-led Torreya Guardians project.27 ... Why examine the question of assisted migration as a relevant topic to ex situ conservation? The first reason is a simple observation: the fact that some of these proposals take explicit root in ex situ conservation projects, making use of the preexisting collections, breeding and testing grounds and reserves in germplasm offered by botanic gardens possessing seed banks; a good number of the authors of those scientific papers are themselves researchers working in botanic gardens. 'Although on its own [ex situ conservation] is not a sustainable solution for conservation, it does provide an essential step in the process of introducing species back to the wild'.35 The Arnold Arboretum of Harvard University proposes the collection and cultivation of 'marginally hardy taxa', which might prove to be more suited to the climate in Massachusetts in the coming decades than the species now living there,36 while researchers at the Missouri Botanic Garden have drafted a white paper calling for 'chaperoned managed relocation.37
          ... What does extinction become, then, in this shifting margin where ex situ conservation and assisted migration projects meet? The event seems to be indefinitely deferred in the deep freeze of seed vaults, that zone of the incomplete where, as suggested by Matthew Chrulew, species, 'rescued from the catastrophe menacing their places of origin, float free of the encroaching risks of existence'.61 Latent life exists at what Thom van Dooren has called the 'dull edge of extinction'62 — the time between the effective extinction of a species and the death of the last individual, made immensely plastic by the practices of ex situ conservation and frozen suspension. Ex situ conservation projects frame extinction as a problem of species plasticity (that which threatens the unadapted) as well as mobility (that which threatens those who cannot move), as Hallfors et al. note.63 Both are problems solvable by making endangered species into immutable mobiles with controllable life rhythms. Or rather, solving the question of mobility might make plasticity obsolete, since all it takes for species that cannot adapt is to follow shifting habitats, and given the means to do so quicker than they would without human intervention (a seemingly accelerationist response to accelerating climate change).64 While this approach coexists with a focus on last individuals and on the preservation of species as genotypes, counter-extinction here takes on a particular, distinctive meaning: safeguarding the mobility of species across landscapes.

    "Climate change threatens some island conifers with extinction" - by Nanditha Chandraprakash, 19 January 2019, Mongabay

    ... There are ways the trees [Bermuda cedar] may find new habitat other than by intentional translocation of selected species. Study co-author Kyle Rosenblad, a research student in Sax's lab, says there will be many cases of what he calls "unmanaged relocation" in the next few decades. This occurs when a species that is cultivated in a new area escapes into the wild and produces a new "insurance population" that could survive climate change. Rosenblad points to the Bermuda cedar as an example.... Many conservation biologists are already talking about translocating species intentionally. Meanwhile humans couldn't stop some cultivated plants from escaping into the wild even if we wanted to."It may make sense to regard these unmanaged relocation events as no-cost conservation tools," Rosenblad says.... "However, given that escape events are going to happen anyway, it will make sense to monitor their progression, and to devote limited control resources only to those populations that are actually becoming invasive," Rosenblad says.

    NOTE: The above news report is based on the paper "Niche syndromes reveal climate-driven extinction threat to island endemic conifers".bu Kyle C. Rosenblad, Daniel L. Perret, and Dov F. Sax, August 2019, Nature Climate Change. EXCERPT: Fundamental and tolerance niches are important for island endemics, because when the climate of a species' native island shifts beyond the realized niche the new conditions could still overlap the fundamental niche, allowing persistence, or the tolerance niche, triggering gradual attrition as death rates overtake recruitment rates4. Unfortunately, fundamental and tolerance niches are difficult to quantify because species' realized niches underrepresent them by unknown amounts.... For naturalized species, researchers can estimate the fundamental niche by circumscribing the range of climatic conditions under which each species has self-sustaining populations, both native and non-native. For plants grown horticulturally, researchers can estimate the tolerance niche by circumscribing the set of conditions under which mature individuals survive unassisted, but reproduction is insufficient to sustain a population.

  • "Facilitating Adaptive Forest Management under Climate Change: A Spatially Specific Synthesis of 125 Species for Habitat Changes and Assisted Migration over the Eastern United States" - by Iverson, Prasad, Peters, and Matthews, 6 November 2019, Forests
    ABSTRACT EXTRACT: We modeled and combined outputs for 125 tree species for the eastern United States, using habitat suitability and colonization potential models along with an evaluation of adaptation traits. These outputs allowed, for the first time, the compilation of tree species' current and future potential for each unit of 55 national forests and grasslands and 469 1 x 1 degree grids across the eastern United States. A habitat suitability model, a migration simulation model, and an assessment based on biological and disturbance factors were used with United States Forest Service Forest Inventory and Analysis data to evaluate species potential to migrate or infill naturally into suitable habitats over the next 100 years.... These tables and maps provide an estimate of potential species trends out 100 years, intended to deliver managers and publics with practical tools to reduce the vast set of decisions before them as they proactively manage tree species in the face of climate change.

    "ASSISTED MIGRATION": The maximum number of potential species, according to this analysis, that may be appropriate to plant in an assisted migration mode, is 19, from the Adirondack Region of New York, with many other cells in the far north also with high numbers of species with potential to migrate in (Figure 7A).

  • "Bellevue to plant 1,000 giant sequoia trees" - by City of Bellevue WA, 14 November 2019, City of Bellevue WA website
    EXCERPT: The City of Bellevue [suburb of Seattle] is planting approximately 1,000 donated giant sequoias this fall in parks and open space throughout the community. On Saturday, Nov. 16, 30 volunteers from Cedar Crest Academy will plant approximately 300 of the two-foot tall seedlings at Wilburton Park. The remainder of the donated trees will be planted at Ardmore, Kelsey Creek and Airfield parks, as well as Forest Park Meadows Open Space. The effort will help the city fulfill its goal of achieving a 40 percent tree canopy. "To ensure a healthy urban forest for future generations, our reforestation efforts need to take climate change into consideration," said Geoff Bradley, natural resources manager in the Parks & Community Services Department. Giant sequoias are a fast-growing, pest-resistant, drought-tolerant species that can live up to 3,000 years.
         Over the last five years, native trees in the city — including western red cedar, western hemlock and Douglas fir — have had a higher mortality rate due to drought stress, which makes trees more vulnerable to fungal disease, insects and other pathogens. This project supports the long-term health of the city's urban forest....

  • "The impact of climate change on forest systems in the northern United States: projections and implications for forest management" - by W. Keith Moser et al., November 2019, chapter in Achieving Sustainable Management of Boreal and Temperate Forests, edited by John A. Stanturf. Editor's note: Chapter obtained via Researchgate; doing an internal "find" for migration offered uses for this webpage. Samples include:


    ... We assumed a generous migration rate of 50 km/century within 100 years; this migration rate represents the high end of average estimates of migration during the Holocene period through extant forest (Davis, 1981; Davis and Shaw, 2001; Schwartz, 1993) although McLachlan et al. (2005) have determined from molecular studies that 25, or even 10 km, may be more realistic for some species that were assisted by seed sources in climatic refugia. We continue to use 50 km/century because we do not assume future formations of climatic refugia. With the combination of results from DISTRIB-II, SHIFT, Modi cation Factors, and current FIA estimates of IV, we are able to present a detailed presentation of (1) species importance currently, (2) the potential changes in suitable habitat by 2100, (3) the adaptability of each species to the changing climate, (4) the capability of each species to cope with the 2100 climate based on adaptability and abundance currently within the National Forest (NF), (5) the likelihood of each species to naturally migrate into the NF, and (6) an assessment of the potential for the species to be used for planting or otherwise promoting within the NF....

  • "Adaptational lag to temperature in valley oak (Quercus lobata) can be mitigated by genome-informed assisted gene flow" - by Luke Brown et al., 25 November 2019, PNAS. UCLA press release on this study can be accessed here.
    SIGNIFICANCE (extract): Conservation strategies often assume that plants are currently growing in conditions well-suited to their growth, survival, and reproduction, regardless of whether this assumption is valid. We show that an ecosystem-foundational species in California, valley oak (Quercus lobata), is already mismatched to current temperature and will likely experience further declines in growth rates as temperatures rise over the next century. Given this mismatch, new approaches to climate change management are needed. By using genomic information and identifying genotypes with faster growth rates under warmer temperatures, we present an approach to mitigate negative consequences of rising temperatures for species that may already be experiencing maladaptation.

    ABSTRACT (extract): If contemporary adaptational lag is commonplace, we will need new approaches to help alleviate predicted negative consequences of climate warming on natural systems. We present one such approach, "genome-informed assisted gene flow," which optimally matches individuals to future climates based on genotype-phenotype-environment associations.

    Editor's note - The above term, "genome-informed assisted gene flow," is well known in forestry circles as "assisted population migration."

    BODY EXTRACT: ... Growth rates were highest on average for valley oaks planted into cooler climates than where they originated as acorns (Fig. 1B and SI Appendix, Table S1). The lack of a peak in growth rates near 0 degrees C Tmax difference expected under local adaptation to current conditions (H1, Fig. 1A) indicates that valley oaks may be in a state of adaptational lag to contemporary temperature (Fig. 1B) and seem more adapted to cooler temperatures approaching levels that were last experienced during the Last Glacial Maximum 21,000 y ago. We found similar patterns when the 2 common gardens were analyzed separately (SI Appendix, Fig. S2). Because the common garden sites in this study were irrigated to maximize the probability of seedling establishment, we were not able to provide an analysis of how precipitation differences impact valley oak growth....

    EDITOR'S NOTE: Because the above research "irrigated" the common gardens sites in order to "maximize the probability of seedling establishment," no conclusion can be drawn as to the relative importance of helping "genes" migrate to match optimal temperatures v. optimal ecological conditions (including precipitation, fog, downslope seepage, slope aspect, existing mycorrhizal networks, and shading by canopy evergreen or deciduous trees). For these reasons, Torreya Guardians studied and documented distinctions in fully mature horticultural plantings at a range of poleward and elevational locations for the endangered Torreya taxifolia, culminating in a "Historic Groves" documentation webpage establishing long-distance assisted migration advocacy for this well-known glacial relict.
        As well, the Brown et al. paper reported that, "However, a number of studies have documented tree species maladapted to their current environment. For example, populations of lodgepole pine (Pinus contorta) have been shown to occupy suboptimal climates, with moderate warming predicted to lead up to a 7% increase in growth, while other tree species are predicted to have higher growth rates in cooler climates than they are currently experiencing." Again, lack of attention to the full panoply of conditions determining optimal geographic siting is apparent; it is common knowledge that for lodgepole pine, maximizing growth rate is far less relevant than an ability to survive at temperatures cold enough to periodically decimate bark beetle populations via winter-kill. Fortunately, these caveats are mentioned in the DISCUSSION SECTION, which does recommend: "Future studies should explicitly test these potential trade-offs to provide a more holistic perspective on how changing climate will affect valley oak fitness." Again, seeking out well established horticultural successes in poleward locations and evaluating those would offer practical opportunities for early and inexpensive holistic conclusions to be gained from such inadvertent long-term ex situ experiments. See for example the video-documentation of horticultural successes (and full naturalization) of Sequoia sempervirens a thousand kilometers poleward of its historic native range: Poleward horticultural plantings of Coast Redwood.

  • "NMSU studying ponderosa pine tree seed sources for future forest management" - by Jane Moorman, 21 December 2019, Las Cruces Sun News.
    EXCERPTS: A warmer, drier climate is predicted to be the norm for the already historically arid forests of the Southwest. Climate change is a natural occurrence. Plant life has been able to adapt to that pace of change genetically and with a natural migration of plants to environments where they can survive. Seed dispersal and the rate of climate change were once in sync. However, the influence of humans through the burning of fossil fuels, releasing of methane gases, and other activities have accelerated the changing climate. Most plants and trees are unable to keep up with this rate of change via seed dispersal.
         New Mexico State University's College of Agricultural, Consumer and Environmental Sciences is conducting research in many areas to help agriculture and forestry professionals adapt to the changing climate. A seven-year study at NMSU's John T. Harrington Forestry Research Center at Mora is providing land managers and researchers with data regarding seed source selection as they restore forests after severe wildfires.
         Ponderosa pines from 75 source locations ranging from southern New Mexico and Arizona to British Columbia have been growing in the northern New Mexico environment. A total of 3,000 seedlings were planted at the research center.
         "Trees from the southern sources are, on average, significantly larger than both the local and northern sources," Burney said of the trees planted at the agricultural experiment station and in natural environments in the region. "Trees from the northern sources have begun to show a decline in growth with some mortality," he said. "As we look at a future climate in the north that is warmer and drier, which will maybe match northern New Mexico's present climate, we now know that the Colorado to British Columbia sources are not going to do very well."
         The study is being used by federal and state agencies across the southwestern United States to develop seed transfer guidelines regarding the range of environment that various source seeds can tolerate. "This information will be used by land managers to assist in the restoration of burned landscapes," Burney said. "As they take into consideration the present climate and changes in the near future, they need to figure out where they are going to get their seed."
         "A lack of seed and nurseries around the world as well as the Southwest limit any assisted migration and restoration effort," Burney said. "As we continue the research on where to plant trees, we still need to build up the seed collection and nursery systems to support these efforts that will only continue to grow into the future."
  • "Traveler Special Report: Threatened And Endangered Parks" - by Kurt Repanshek and Rita Beamish, December 2019, press release/report of
    EXCERPTS ON ASSISTED MIGRATION: ... Noting the Arctic's particular sensitivity to warming, Jon Jarvis, former head of the Park Service who was once superintendent of Wrangell-St. Elias, said unprecedented impacts like fires of unparalleled size and intensity are evident in Alaska and transforming the landscape. For instance, he said, "You can see the climate changes as forests spread and become established over these areas of melting permafrost and receding glaciers."
         Old paradigms of park management will need to change, Jarvis told the Traveler. Aside from carbon-emission reduction, he said, the Park Service must double-down on broad strategic management that starts with scientific and traditional knowledge and includes public education.
         With ecosystems changing in ways not yet fully understood, "You can only do so much," for strict conservation, he added. "We are left with adaptation. We still have a mission, and it's for future generations. If we want to maintain the parks in as unimpaired a status as we can — we have to be smarter, use science and use the best strategies — some at landscape scale, some protecting refugia — even some assisted migration to allow some species to survive," he said. "In some cases, we may have to say goodbye. The parks will still be there. It's just they will be different."


  • "Science can help us adapt to climate change, but first we have to admit it is happening" - by Graham Readfearn, 2 January 2020, The Guardian.
    EXCERPT: ... "Climate change mitigation is about avoiding the unmanageable," says Dr Alistair Hobday, a research director at CSIRO Oceans and Atmosphere and a co-author of the analysis. "Adaptation is about managing the unavoidable. Adaptation is going to be critical to Australia. Mitigation has to be global, but adaptation can be local." Hobday says that as well as understanding why some might see climate change as a lower priority, another barrier is public resistance to translocating species that are not able to adapt or move as temperatures and rainfall change. "These are situations where people resist doing something despite the evidence that the animal's world is changing," he says.
         The only example of a project like that in Australia is a pilot study that has moved 35 captive-bred western swamp turtles to new sites in southwest Western Australia. Prof Lesley Hughes, of Macquarie University, and also an author on the analysis, says there has been resistance to "interventions" like translocation, but this needs to change. Despite 30 years of research looking at how climate change would affect habitats, she says, very little work has been done to protect species....

  • "Relocating koalas to New Zealand is a nice idea, but it isn't a good one" - by James Russell, 15 January 2020, The Guardian.
    Editor's note: Following the 2019 Australian bushfires and the tremendous loss not just of forests (including rainforests) but of the animals within them, it seems that moving koalas to New Zealand is a redo of the 20th century impulse to move polar bears to Antarctica. Translocation may indeed be necessary — but moving poleward on the same continent is where one must begin searching for sites. Translocating anything to an altogether different land mass (be it continent or island) is necessarily fraught with peril and is not on par with simple poleward, same-continent translocations.

    EXCERPT: "A petition currently doing the rounds on the internet advocates for koalas to be introduced to New Zealand, in response to the horrific scenes of native animals suffering in the Australian bushfires. New Zealand has more than 23,000 hectares of eucalyptus plantations so why not? Isn't that the spirit of Anzac cooperation?"

    "This is not how sequoias die; it's supposed to stand for another 500 years" - by Patrick Greenfield, 18 January 2020, The Guardian

       SUMMARY by Connie Barlow: This lengthy, illustrated article in The Guardian is a tear-jerker. I already knew this past fall of the shocking losses of Giant Sequoias in the Sierras, as I communicated with one of the coauthors of the in-press paper — because I had come upon a newly fallen branch of a Coast Redwood that also showed bark beetle tunnels, despite the "knowledge" that bark beetles cannot attack redwoods. What I see now is that, yes, bark beetles cannot penetrate the thick trunk bark, but the bark on even the most massive branches (of a Coast Redwood) is no thicker than that of a yew. So the beetles kill redwoods slowly, out of sight in the high canopy, branch by branch. In contrast, pines and firs and spruce wiped out in the western USA are killed by bark beetles whose tunneling and fungal follow-up girdle the main trunk. The damage is readily apparent even at ground level.

  • "Assisted Tree Range Expansion: How You Can Help" - by Jeannie Williams, Conservation Easement Monitor, 15 January 2020, posted on Leelanau Conservancy website (Traverse City, Michigan)

    EXCERPT: I've walked nearly 100 conservation easements in Leelanau County this year. These walks have given me a good look at the state of our forests. Between the loss of ash trees from emerald ash borer and beech trees falling in increasing numbers in recent years from beech bark disease, plus the high winds that came through in 2015, it is easy to worry about the state of our forests. Can we lose this many trees and still keep a functional forest? What can a landowner do in response to these serious disturbances? One course of action, as a landowner, is to let nature take her course. I have incredible faith in nature and in the forest to recover from damage. However I have come to see that "let nature take her course" ignores the limitations that nature faces and gives humans a free pass. Leelanau's forests face four important challenges: invasive species, non-native disease, fragmentation, and climate change. That means we humans are needed more than ever to help Mother Nature maintain forest health.... New tree diseases are another impediment facing Mother Nature. Do you remember American elm? Elm was once common throughout Michigan and today is essentially eliminated from our forests by invasive pathogens. Now, ash, beech and red oak are also facing diseases. On the horizon, eastern hemlock are threatened by hemlock wooly adelgid and maples by Asian longhorned beetles. Without these tree species, often the most common species in the forest, it becomes much more difficult for nature to create a functional forest on her own.

        ... Given your conservation desires, and nature's challenges in assisting you in the face of the rapid changes occurring in our forests, we encourage you to take active steps to manage your land. One satisfying and effective action is to plant trees, annually if possible. This year, consider planting trees whose native ranges end just south of here, yet are projected to do well in our region according to research out of the USDA Northern Hardwoods Research Station, through a process called assisted tree range expansion. Trees like swamp white oak, shagbark hickory, hackberry, tulip tree, sassafras, and black gum have high potential to thrive in our forests since climate change has made our area hospitable for species that are native to southern Michigan. These trees also have the potential to fill in wildlife food gaps, which are imminent as beech continues to decline and nutritious beech nuts disappear. Black bears will need a food source that replaces beechnut and these trees can help.
         This spring, the Leelanau Conservation District will be selling a selection of trees whose comfortable ranges are expanding north at their annual tree sale. You may order and purchase trees in bundles of five (single species, not mixes). Then, get to know your trees by visiting them at least once a year and checking in on their growth and health. You can participate in the Conservation District�s new citizen science initiative, the Assisted Tree Range Expansion Program (ATREP) by taking some basic annual measurements: height and then diameter when the tree is over six feet tall. Data from ATREP participants will help our Conservation District and agencies such as the office of Environment, Great Lakes, and Energy (EGLE) and Sleeping Bear Dunes National Lakeshore assess the viability of planting these species on a wider scale.... Find out more about the Assisted Tree Range Expansion Project (ATREP) here: Thank you for being a forest steward.
  • "Assisted gene flow in the context of large-scale forest management in California, USA" - by Derek J.N. Young et al., January 2020, Ecosphere
    EXCERPT: ... Based on a long history of studies that often identify strong local adaptation in tree populations (Langlet 1971, Conkle and Critchfield 1988, Ying and Liang 1994, Howe et al. 2003, Kitzmiller 2005, St Clair et al. 2005, Savolainen et al. 2007, Wright 2007), many forest managers have historically prioritized the use of seeds collected from near the planting site while also incorporating a reasonable range of genetic variation (Ledig and Kitzmiller 1992). This approach helps to ensure that most of the planted trees are well-adapted to the environmental conditions of the planting site and that planted populations maintain adaptive capacity in future generations (Savolainen et al. 2007, Alberto et al. 2013). Matching seed source and planting site environment often results in increased performance of planted trees relative to alternative approaches that do not carefully account for the provenance of planted trees (Langlet 1971, Aitken and Bemmels 2016).
         Appropriate seed source selection methods are less clear when environmental conditions are changing. Given a scenario of progressive warming and drying, for example, it may make sense to select seeds from source environments that are hotter and drier than the planting site, as genotypes from those environments may be better adapted to certain environmental conditions (e.g., frequent drought) that may eventually characterize the planting site (Aitken and Whitlock 2013). The approach of intentionally moving genotypes of a given species to new locations within the species range in order to track changing environmental conditions is referred to as assisted gene flow (Ledig and Kitzmiller 1992, Aitken and Whitlock 2013). Assisted gene flow differs from assisted migration (also known as assisted colonization or managed relocation; McLachlan et al. 2007) in that the latter concepts include managed relocation of individuals or populations of a species beyond the species' historic geographic range limit as opposed to moving them within the existing species range. However, many of the same motivations, guiding principles, and cautions apply to both assisted gene flow and assisted colonization (Aitken and Whitlock 2013).
         ... We sought to evaluate the potential outcomes of assisted gene flow applied in largescale postfire forest restoration plantings and gain insight into potential limitations or other considerations unique to implementation of assisted gene flow in an operational context. To this end, we studied postfire plantings of five different tree species conducted by the USDA Forest Service (USDA-FS) at three sites in California. [FIVE SPECIES = Douglas-fir, Incense cedar, Ponderosa pine, Jeffrey pine, and Sugar pine.]
         ... In the present study, we evaluate the growth and survival of seedlings that originated from seed lots that are representative of the planting site, as well as seed lots representing lower elevations, at three sites that were planted following severe wildfire. For the duration of this experiment, California experienced a drought so extreme it had no historical precedent (Robeson 2015). The drought offers the potential opportunity to gain insight into expected outcomes of assisted gene flow in an overall hotter and more variable future climate. We additionally evaluate the limitations of relying on operational seed lots with imprecise collection location data, and we interpret our results (as well as implementation and expected outcomes of operational assisted gene flow in forests generally) in this context.
  • "Assisted migration across fixed seed zones detects adaptation lags in two major North American tree species" - by Julie R. Etterson et al., 14 February 2020, Ecological Applications
    EXCERPT OF ABSTRACT: ... Collectively, these results suggest that state seed sourcing guidelines should be reexamined to permit plantings across seed zones, a form of assisted migration. More extensive experiments (i.e. provenance trails) are necessary to make species-specific seed transfer guidelines that account for climate trends while also considering the precise geographic origin of seed sources. [locale was Minnesota USA; two species tested = Northern Red Oak and Bur Oak].
  • "As Warming Alters Alaska, Can a Key Wildlife Refuge Adapt?" - by Miranda Weiss, 5 March 2020, Yale Environment 360
    SUMMARY: Lengthy in-depth article on the controversy within Alaska of whether to compensate for climate-caused loss of native spruce forests in Kenai National Wildlife Refuge by bringing in non-native Lodgepole Pine, non-native American Bison, and non-native Black-tailed Deer. The term "assisted migration" appears once in the article, while "proactive measures to adapt, including introducing bison ..." is the main descriptor. QUOTE: "As [John] Morton witnessed the transformation of the Kenai reserve and realized that profound ecological change was inevitable, he began to see that scientists and managers might need to play an active role in directing change to meet conservation goals. 'We know we�re going to experience mass extinction,' he says. 'We have to do something different.'"
  • "As climate changes, longleaf pines move north — with help" - by Timothy B. Wheeler, 17 April 2020, Bay Journal [for Chesapeake Bay watershed]
    EXCERPTS: ... It's all part of an experiment in "assisted migration" being conducted by The Nature Conservancy. The nonprofit conservation group wants to see if human intervention can help an ecologically important forest ecosystem adapt as climate change alters its range.... But changing climate conditions are posing a challenge for sustaining longleaf pine forests and the wildlife that occupy those ecological niches. With temperatures rising at an unprecedented clip, researchers have projected that plants in general could have to migrate up to 3 miles a year to survive. That's many times the movement rate of many species, particularly trees like longleaf pines.
         ... "It's no longer a static ecosystem," said Deborah Landau, a concervancy ecologist. "We can't just buy it and protect it and hope for the best. The times are changing, the climate is changing. We have to try different things."
         ... The conservancy and its partners hope this experiment will give the trees a head start on relocating north to Maryland. "What we're hoping to learn is how these more southerly species do as temperatures increase, as we get more extreme weather events," Landau explained. Longleaf pines can handle extended periods of drought and rainfall, she noted, and their deep taproots help them withstand the strong winds of hurricanes.
         ... It may seem incongruous for a conservation group to introduce a tree not native to Maryland. But Landau said it isn't really a stretch. After the Ice Age, she explained, longleaf pines slowly extended their range northward from Florida. They had reached the James River in Virginia about 400 years ago, when English settlers arrived and began cutting them down. If that hadn't happened, she argued, they may very well have found their way to the Delmarva Peninsula, as other southern pines did.


    "Playing the hand of God': scientists' experiment aims to help trees survive climate change", by Ashley Stimpson, 8 July 2020, The Guardian. Tagline: "Scientists use a strategy called assisted migration in an attempt to rescue tree species from inhospitable conditions." And back in April 2014, Scientific American had a story about this same project: "Can Flamethrowers Help Trees Migrate?".
  • "In Fast-Warming Minnesota, Scientists Are Trying to Plant the Forests of the Future" - by Brady Dennis, 29 April 2020, Washington Post:
    EXCERPTS: ... But the boldest part of the experiment is known as "assisted migration" — planting of trees that once would not have been found here, but that are expected to flourish in the future that scientists foresee in Minnesota's North Woods.
         Brian Palik [a longtime ecologist with the Forest Service's Northern Research Station] knows that the approach is controversial and that it could be expensive to deploy on a wide scale. But he also says that the forests that Minnesotans cherish — the ones that support the timber industry, recreation, tourism and wildlife — face serious risks in the decades ahead unless humans intervene.
         "The worst-case scenario is if we don't do something like this, we'll have no forest," he said. "Our broad objective is to look at ways to keep forests on the landscape. It may be a different forest. I like to say that it may not be your grandfather's forest, but it will be your grandchildren's forest."
         Even as the changes to the state's iconic forests are still unnoticed to many, Palik feels an urgency to lay the groundwork to keep the woods as productive and alluring as they are now. The climate is changing "at a rate that's unprecedented in geologic history," he said. "And plants, including trees, don't migrate at that same rate." There are also obstacles — roads, parking lots, agricultural fields — that make the trees' slow migration north more difficult. "So we're helping things move," he said.
         ... "Climate change has stealthily set in motion a hundred little things that together will most certainly render northern forests of the future unrecognizable," Meredith Cornett [of the Nature Conservancy] wrote. "For me, that meant embracing the notion that to 'save' the great Northwoods might mean transforming it." That realization led her to adaptation.
         "This is about trying to help the forest itself transform and keep pace with a rapidly warming climate," she said as she walked through the serene woods. "We see ourselves as troops with a mission — to help the forest help itself."
         In recent years, Cornett and her colleagues have focused on a simple goal: to keep the "woods" in the North Woods, even if that means something different from generations past. She thinks that a functioning forest — as opposed to the shrub land or grassland that could dominate here if Minnesota's warming continues unabated — is critical to wildlife habitats, carbon storage, the timber industry and water quality.
  • "40,000 trees being planted to help West Michigan forests through climate change" - by Brad Devereaux, 16 April 2020, Michigan Live.
    EDITOR'S NOTE: "Assisted migration" has now, rightfully, been sidelined to use primarily for climate-endangered species, such as the Florida Torreya, on whose advocacy website this scholarly links page began in 2007. Instead, "adaptive management" of wild and urban forests is now the preferred term, which emphasizes the aim to maintain a healthy and diverse forest canopy. Accordingly, genetics drawn from southerly populations of current tree species and planting of seeds and seedlings from southerly species are becoming standard tools for maintaining forest health in the decades ahead. For example, the news article cited here features an initiative of the Southwest Michigan Land Conservancy (SWMLC):
    "... The project area spans what ecologists call the 'tension zone,' a region where northern tree species meet southern tree species and they blend together. Any Michigander who has driven 'up north' from the southern part of the state has experienced the tension zone as oaks and hickories start to give way to birches and pines. As summer temperatures become warmer and winters become milder, historically southern species like shagbark hickory are likely to do better here, while northern species like paper birch are likely to struggle and their range is likely to move further north. At the Wau-Ke-Na Preserve, SWMLC is considering which species of planted trees may do best after invasive plants are treated in the struggling ash forests. Black gum and sycamore, for example, are two tree species that like the wet conditions found at the preserve, and if planted could help to refill the open canopy over time. 'I've seen these species a lot more in southern Michigan and northern Indiana, but at this point they're pretty uncommon this far north. If we plant them here now, not only could they handle the warmer summer temps here, but they may even thrive over time, and help keep invasives from taking over again,' Brown said. MORE INFORMATION on this project.
  • "Recent evidence of Mexican temperate forest decline and the need for ex situ conservation, assisted migration, and translocation of species ensembles as adaptive management to face projected climatic change impacts in a megadiverse country" - by Cuauhtemoc Saenz-Romero et al., 20 April 2020, Canadian Journal of Forest Research
    ABSTRACT: Symptoms of forest decline, apparently due to climate change, have become evident in the last 10 years on the Trans-Mexican Volcanic Belt and northwestern temperate forest of Mexico, particularly at the xeric (low elevational) limit of several forest tree species. We review and provide recent evidence of massive infestation of timberline Pinus hartwegii Lindl. by the mistletoes Arceuthobium globosum Hawksw. & Wiens and Arceuthobium vaginatum (Humb. & Bonpl. ex Willd.) J.Presl; insufficient Abies religiosa (Kunth) Schltdl. & Cham. seedling recruitment at the Monarch Butterfly Biosphere Reserve; indications of inbreeding and defoliation in endangered Picea chihuahuana Mart�nez, Picea martinezii T.F. Patt., Picea mexicana Mart�nez, and extreme southern populations of Pseudotsuga menziesii (Mirb.) Franco; and the incidence of unusual pest and disease outbreaks (e.g., Dendroctonus Erichson, 1836 spp., Neodiprion autumnalis Smith, and Phytophthora cinnamomi Rands) in several conifer and oak species. We also discuss a difficult question: Is natural genetic variation sufficient to provide populations with the adaptive variation necessary to survive the natural selection imposed by projected climate change scenarios, or will phenotypic plasticity be exhausted and populations decline? Controversial ex situ conservation within natural protected areas, assisted migration, and translocation of species ensembles are discussed as options by which to accommodate projected climatic change impacts on the management and conservation practices of the megadiverse Mexican temperate forest.

    EXCERPTS: ... Although our analysis is focused on Mexico, it is important to note that Mexico is a megadiverse country (Mittermeier 1988; Ramamoorthy et al. 1993) and is perhaps the most important center of speciation and diversification of the genera Pinus L. (pines; Styles 1993) and Quercus L. (oaks; Nixon 1993) worldwide. Thus, a possible reduction of Mexican forest genetic resources due to climatic change could imply reduced opportunities to utilize the forest genetic diversity that currently exists in Mexican forests in tree breeding and ex situ conservation programs in countries where Mexican pines are planted as exotics (Dvorak 2000).... Another apparent indication of increasingly stressful environmental conditions for forest tree populations is the lack of seedling recruitment, even in stands within the well-protected core zone of the MBBR. A recent survey that followed hundreds (>600) of naturally regenerated Abies religiosa seedlings in the core of the MBBR indicated that most of the recently emerged seedlings die during the warm and dry season (March�May, especially in April). Results indicate that the soil is becoming too dry in April, apparently crossing a critical moisture content threshold, provoking massive mortality among the seedlings that emerged during the previous rainy season.
         Conceptualization of assisted migration as a reasonable management option, considering the grim projections of climatic change, undoubtedly make sense; however, its implementation remains a complicated task that is full of risks, given that translocation is required at present, at sites where the projected future climate does not yet occur, and there is thus a real possibility of frost damage to young, recently planted seedlings. Moreover, the local microenvironment, herbivory, pathogens (Grady et al. 2015), plant-plant interactions and their evolutionary consequences (Grady et al. 2017), and intraspecific interactions under certain circumstances might outweigh climate as determinants for successful species establishment, an issue that calls for further research (Bucharova 2017). In other words, genotype translocation does not necessarily guarantee seedling survival. In addition, there is a reluctance on the part of some foresters, and even more so for some ecologists (it is our impression, at least in Mexico), to adopt assisted migration. This is perhaps because traditional forest management and in situ conservation were developed on the premise that tree establishment takes place in a relatively constant climate (Park and Talbot 2018).
         There have been two experiences of experimental assisted migration with conifer species in Mexico. The first experience was with three pines (Pinus devoniana, Pinus leiophylla Schiede ex Schltdl. & Cham., and Pinus pseudostrobus), and four provenances for each species, with reciprocal transplants at contrasting elevations (2100, 2400, and 2700 m a.s.l.), in the pine-oak forest of the indigenous community of Nuevo San Juan Parangaricutiro, Michoac�n state, central-western Mexico (Castellanos-Acuna et al. 2015). The second experience was an upward shift in elevation of Abies religiosa provenances (10 at one site at 3440 m a.s.l. and six at 3360 m a.s.l.), using local shrubs (mostly Baccharis conferta) as nurse plants to protect the young fir seedlings from the extreme temperatures, at the core zone of the MBBR in Estado de M�xico, central Mexico (Carbajal-Navarro et al. 2019). In both cases, the lesson in brief is that, in terms of survival and growth rate, the translocation of seed sources shifting upwards in elevation is viable (with no substantial reduction of growth or survival, at least during the experimental period of about 3 years of observation in the field) when the upward shift in elevation does not exceed 400 m from the seed source to the planting site. Such translocation aims to compensate for a projected increase of temperature up to 2 degrees C (given a lapse rate of 0.5 C for each 100 m of elevational difference; Saenz-Romero et al. 2010). However, for the shade-tolerant species Abies religiosa, in addition to the upward shift in elevation, it is absolutely necessary to plant the fir seedlings under the shade of shrubs serving as nurse plants or else the mortality will be too severe (Carbajal-Navarro et al. 2019). There are also some differences among species: Pinus pseudostrobus and Pinus devoniana presented much more decreased growth when exceeding an upward shift of more than 400 m in elevational difference between seed source and planting site, whereas Pinus leiophylla seemed to be unaffected, displaying great phenotypic plasticity (Castellanos-Acuna et al. 2015).
         Migration of complex ensembles is desirable because the persistence of valuable species depends in many cases on the presence of other species, including symbionts, pollinators, or facilitators (e.g., nurse plants). Moreover, because some ecosystem functions such as resilience depend at least partially on diversity, migrating ensembles of species can increase the chances of creating more resilient communities (Loreau et al. 2002). Consideration of Units of Assisted Migration of Species Ensembles is a strategy that might allow a practical community-based approach (Saenz-Romero 2018). These units must include species of value for human use or conservation, as well as those that facilitate establishment of other plant species and migration of animals, symbionts, and other species that play key roles in biotic interactions. Within this latter group are important soil microorganisms such as growth-promoting rhizobacteria and mycorrhizal fungi, as well as species that attract pollinators.

  • "Combining US and Canadian forest inventories to assess habitat suitability and migration potential of 25 tree species under climate change" - by Anantha Prasad et al., June 2020, Diversity and Distributions.
    EXCERPTS: ... To our knowledge, this is the first attempt to combine the forest inventories of the United States and Canada to model range-wide habitat suitability, using a continuous response variable of relative abundance in combination with potential tree migration under climate change.... Results: At a continental scale, many species in the conterminous United States lose suitable climatic habitat (especially under RCP 8.5) while Canada and USA's Alaska gain climate habitat. For most species, even under optimistic migration rates, only a small portion of overall future suitable habitat is projected to be naturally colonized in approx. 100 years, although considerable variation exists among species.
  • "By paying attention, tribes in the Northwoods are leading the way on climate change" - by Samantha Harrington, 8 June 2020, Yale Climate Connections.
    EXCERPTS: ... Fifteen years ago in Grand Portage, the tribe began to notice and study the decline of brook trout in Trout Lake, a 61-acre lake on the reservation. Eventually the lake warmed so much that temperature-sensitive trout could no longer survive. The tribe restocked the lake with walleye and yellow perch, which thrive in warmer water. But Minnesota's Department of Natural Resources has not taken similar measures in other lakes in the northern part of the state. "I think we're going to see a massive loss of trout species in northeastern Minnesota, and I think that the Minnesota DNR is going to have to really consider: Is it acceptable to have a whole bunch of lakes with no fish, or do we start trying to change to fish communities that are a bit more resilient?" asked Seth Moore, the director of biology and environment at the Grand Portage Band. "That's a no-brainer in my opinion. It almost feels like they're a decade late."
         The guiding force behind much of this early work is the Anishinaabe emphasis on the connectedness of all beings and actions. "We are here because of our relationship with the land," Dupuis said. "In many of our stories, it's our relationship with the Earth and the animals, the swimmers, the flyers that needs to be in harmony, and if we skew that balance, bad things happen. So our relationship with the Earth is primary — to be aware of what we�re doing and considerate in what we do."
         Northwoods lie in a transition zone between southern forests and the boreal forests of the north. Many of the region's cold-loving species, like paper birch and moose, are living in the southernmost reaches of their range. Warmer winters have already prompted the decline of some cold-weather species and the northerly migration of new species that were once killed off by the cold. In addition to their inherent value as beings, many vulnerable species are culturally significant for their direct roles in tribal ceremonies and subsistence. Ash trees, threatened as warmer temperatures allow emerald ash borer to gain a stronger foothold in the forests, have long been used to make baskets, fishing tools, pipe stems, and lacrosse sticks. Alex Mehne, forest manager of the Fond du Lac Band, said that black ash trees — which are the dominant tree species in the area — are critical in maintaining water levels in wetlands. Black ash trees grow in large groups in forested wetlands, where they absorb water from the ground.
         As they noticed these vulnerabilities, Anishinaabe people began work to ease the coming changes. The Fond du Lac Band is experimenting with planting alternative wetland tree species to see if they could play a similar role in the ecosystem to the ash trees. So far, swamp white oak and silver maple seem to be succeeding.
  • "New Seed-Collection Zones for the Eastern United States: The Eastern Seed Zone Forum" - by Carolyn Pike et al., July 2020, Journal of Forestry.
    ABSTRACT: "Reforestation and restoration efforts have traditionally relied on 'local' seed sources as planting stock. The term 'local' has different meanings in different locales, since no single set of seed-collection zones has yet been widely adopted across the eastern United States. Given concerns about mitigating the effects of climate change, forest managers are increasingly seeking to move seed sources in a process called assisted migration, which would be facilitated if a common set of seed-collection zones were available. We developed a map of 245 seed-collection zones for 37 states by combining two ecologically important layers: plant hardiness zones and ecoregions. These new seed-collection zones should be used by seed collectors and nurseries to describe the origin of seed for plants and trees in the eastern United States. Common garden studies remain the gold standard for determining how far to move seed from any particular seed-collection zone. For species that have not been field-tested, seed movement that is limited either within a seed-collection zone or between adjacent seed-collection zones is a reasonable general guideline.
  • "Importance of species translocations under rapid climate change" - by Nathalie Butt et al., 13 October 2020, Conservation Biology.
    ABSTRACT: "Species that cannot adapt or keep pace with a changing climate are likely to need human intervention to shift to more suitable climates. While hundreds of articles mention using translocation as a climate-change adaptation tool, in practice, assisted migration as a conservation action remains rare, especially for animals. This is likely due to concern over introducing species to places where they may become invasive. However, there are other barriers to consider, such as time-frame mismatch, sociopolitical, knowledge and uncertainty barriers to conservationists adopting assisted migration as a go-to strategy. We recommend the following to advance assisted migration as a conservation tool: attempt assisted migrations at small scales, translocate species with little invasion risk, adopt robust monitoring protocols that trigger an active response, and promote political and public support."

    EXCERPTS: "We examined barriers to the use of assisted migration as a species conservation tool for adapting to climate change and how these barriers could be overcome to ensure that assisted migration is used more widely. We focused on 3 primary barriers that are seldom explored: sociopolitical, knowledge and uncertainty, and time-frame mismatch, although we acknowledge the existence of others, such as legal and ethical constraints. Our aim was to help chart a way forward to facilitate the use of assisted migration and contribute to slowing the global extinction rate."
         "... Assisted migration (also called assisted colonization or managed relocation [H�llfors et al. 2014]) has been considered part of the translocation toolkit, officially since 2013, and has been discussed in the scientific literature for more than a decade. A search of a subset of the conservation literature (Conservation Biology, Conservation Letters, Biological Conservation, and Biodiversity and Conservation journals) revealed over 350 articles mentioning climate-assisted migration and over 550 mentioning climate-change translocation since 2010. Yet, even though climate change will make the current habitat of many species unsuitable (e.g., Chauvenet et al. 2013; Verges et al. 2014; Gallagher et al. 2019) translocation continues to be primarily concerned with reintroducing species to areas from where they have been extirpated (Soorae et al. 2010, 2011, 2013, 2016, 2018) or moving individuals between populations to reduce the likelihood of local extinction from a range of threats (Hedrick & Fredrickson 2010) (Fig. 1).
         "... Moving species to new areas outside their current or previous ranges has not been implemented widely (Heikkinen et al. 2015), and examples are few. In Western Australia, one of the rarest reptile species in the world, the Western swamp turtle (Pseudemydura umbrina), threatened by drying climate conditions, has been translocated to areas south of its current range that are projected to be hydrologically suitable in the future (Dade et al. 2014; Lewis 2016; Mitchell et al. 2016). In the Scottish Highlands, an alpine lichen (Flavocetraria nivalis) underwent experimental translocation to higher elevations to inform modeling of habitat suitability under climate change (Brooker et al. 2017), and two butterfly species were introduced to sites outside their native range in northern England (Willis et al. 2009). In all of these examples, the current ranges of the species are projected to become unsuitable due to increasing temperatures. The Florida torreya (Torreya taxifolia), however, is an example of a species whose existing range had already become unsuitable and so was translocated 600 km north to a more suitable area (Barlow & Martin 2004).
         "Assisted migration has been recommended as a climate-change conservation action due to its necessity in the conservation of species that are not able to disperse unaided to climatically suitable locations (e.g., Heller & Zavaleta 2009; Chauvenet et al. 2013; Reside et al. 2018). Conservation scientists have already constructed decision frameworks (e.g., McLachlan et al. 2007; Richardson et al. 2009; Rout et al. 2013) designed integrated strategies for selecting sites and species (e.g., Chauvenet et al. 2012; Harris et al. 2013; Gallagher et al. 2015), begun to test adaptive versus acclimatization effects in translocated species (Morikawa & Palumbi 2019), and provided recommendations about the best time to carry out assisted migration (McDonald-Madden et al. 2011). However, given the pervasiveness of the climate crisis and impending extinctions of species (IPBES 2019) and ecosystems (Bland et al. 2017), surprisingly few cases of climate-change translocations exist.
         "There has been much written about the ethics of assisted migration. Researchers have examined whether a species' instrumental, ecological, or intrinsic value justify the risk and expense of moving them (Sandler 2010), make calls for pragmatic ethical analysis (Minteer & Collins 2010) that incorporates risk (Ahteensuu & Lehv�virta 2014), and acknowledge that solutions to the philosophical, political, and practical challenges around translocation are complex and multifaceted (Hewitt et al. 2011; Schwartz et al. 2012). The legal aspects of assisted migration are also important to consider, and regulatory policy should support ethical considerations by facilitating thorough appraisals of species' conservation plans (Camacho et al. 2010; Schwartz et al. 2012). Conservation scientists and practitioners themselves are of course also subject to ethical concerns and considerations. We argue that despite several barriers to adopting assisted migration, it is urgent that it be added to the standard conservation toolkit because climate change is (or soon will become) the primary threat for many species. It is therefore critical to be open about these barriers to identify pathways to overcome them.

  • "Cloud Forests: Narrow bands of biodiversity filled with mist, fog and mystery" - by Monica Evans, 26 October 2020, Global Landscapes Forum.
    EXCERPTS: ... While projects like this might make an impact on ecosystems and communities at the ground level, a more existential threat looms large over the planet's cloud forests: climate change. A 2019 study estimated that climate change could shrink and dry 60 to 80 percent of cloud forests in the Western Hemisphere in as few as 25 years. "These forests exist in a very narrow attitudinal range, and this altitudinal range is defined by the climatic condition," says Nasi. "They can't go down, they can only go up — which means that with the climate changing, the altitudinal range where they are growing is going to be narrower and narrower, until it finally disappears.... To that end, the infectiously optimistic Toledo-Aceves is now researching 'assisted migration' for beleaguered cloud-forest inhabitants. "We're trying to help species move to sites that, in the foreseeable future, might have the right conditions for them to thrive," she said. For the past five years, she and her colleagues have been running experiments planting native seedlings in long lines up mountainsides, to see which ones survive at higher elevations. "And what's beautiful is that we have had very high survival rates for many different species," she says. "So that indicates to me that it is possible. Of course, there are plenty more components to the ecosystem that we still need to research. But I do think that there is a lot of hope."
  • "Widespread underfilling of the potential ranges of North American trees" - by Benjamin J. Seliger et. al, 11 November 2020, Journal of Biogeography
    Results: The potential ranges of North American trees and shrubs are broadly underfilled (mean = 48%). Furthermore, range filling is positively correlated with geographic range size. Large-ranged species have higher range filling than the null model, and shape ratios indicative of climatic restrictions. Small-ranged species showed a stronger influence of dispersal limitation.

    Main conclusions: Climate explains only about half of tree species' ranges, and the signal of climatic equilibrium increases with range size. Small-range species show high levels of climatic disequilibrium, which is likely be driven by combinations of dispersal lags, and undetected environmental factors or biotic interactions. These results highlight the importance of conserving small-ranged species and the difficulty of forecasting how their distributions will shift in the coming centuries.

    ... The Rocky Mountain Bristlecone Pine (Pinus aristata) had the lowest range filling of any species we analysed (1.4%; Table S5), and Sassafras albidum had the highest (99.7%; Table S5).

    ... As such, we may need to embrace emerging conservation efforts such as managed relocation or horticultural naturalizations to ensure reliable persistence for our most vulnerable tree species.

    NOTE: A popular account of this paper was published by journalist Zach St. George in Sierra Magazine, using the term "assisted migration":

    ... The question of what is constraining species' ranges is at the heart of the debate over whether people should move species to suitable places, a conservation method known as "assisted migration." Since the 1980s, botanists have worried that many plants would be unable to keep pace with the rate of modern climate change. For small, isolated species, this could mean extinction. While people have often moved species from one part of the world to another for more mundane reasons, the idea of doing so as a conservation method has proven controversial. Skeptics worry about inadvertently creating new invasive species, and about disrupting the existing ecosystems that would receive the assisted migrants.
         But there is also the question of whether species actually need the help. As ecologist Mark Schwartz wrote in a 2004 paper arguing against assisted migration, "the arguments about range and climate rely on very important assumptions that are not well justified. We usually do not have empirical data from which to judge whether narrowly distributed species are, as assumed, limited by climate and not by other environmental factors.... As a consequence, I believe that we should exercise caution."
         On the one hand, the Biogeography study, which shows species widely in disequilibrium with climate, seems to reinforce Schwartz's point. "People advocating that we need to assist movement should think twice," says Carsten Rahbek, a macroecologist who was not involved in the Journal of Biogeography study. "It looks like these small-ranged species are not determined by contemporary climate, and that kind of undermines the necessity of people to go in and help them."
         Svenning draws a different conclusion. Tree species, he says, have had more than 10,000 years of relatively stable climatic conditions since the end of the last ice age and still haven't reached equilibrium with the climate. "We're now expecting strong climate change in the next decades and centuries," he says. "It's super unrealistic to expect many species to track this. They couldn't do it across these 10,000 years. They can't do it in this short time frame."
         Seliger says that, in an odd way, both perspectives can be true. The current distributions of many tree species might have little to do with the current climate, and, for many of those species, climate change could be the biggest threat in the future. "Unfortunately," he says, "the debate is going to go on."
         Whether people take the possibility that many species are out of sync with the current climate as evidence for or against assisted migration, Svenning says he hopes it will lead them to consider a slightly broader view of whether species are "native" to a particular place. The places we find species today, he says, represent only where they've managed to reach.
         It seems to be true, at least, of Kentucky yellowwood. For decades, people have planted it in yards and along streets across eastern North America. Today, the species inhabits an area far greater than it ever managed to reach on its own.
  • "Translocation of an arctic seashore plant reveals signs of maladaptation to altered climatic conditions" - by Maria Hallfors et. al, 20 November 2020, PeerJ 8:e10357.
    EXCERPT of CONCLUSIONS section: Siberian primrose, a habitat specialist and poor disperser with small and fragmented populations that harbour low genetic variability and a limited thermal tolerance, is an example of a species likely to suffer from the lack of adaptive capacity under rapid climatic change. Proactive conservation methods, such as assisted migration, may be needed in order to save this species. Overall, our results cause concern about the viability of the Siberian primrose, especially the northern variety, for which the detrimental effects of climate change may become evident within a few decades. In addition, these findings remind us of the need to take the population level into account when modelling the effect of climate change on species....

    EXCERPTS from popular press version: "Siberian primrose has not had time to adapt to climate change": Siberian primrose, a species protected under the Habitats Directive of the European Union, spread northward from southern areas to the current Bothnian Bay as well as, through another route, to northern Norway with the gradually receding ice after the Ice Age. Compared to today, the warming of the climate was very slow at the time.... In 2013, researchers at the Universities of Helsinki and Oulu planted both the Norwegian and Finnish varieties at five different botanic gardens: in their home environments in Svanvik, northern Norway, and in Oulu, northern Finland, as well as in Rauma and Helsinki further south in Finland and in Tartu, Estonia. As expected by the researchers, both varieties fared poorer in the southern gardens compared to Oulu and Svanvik, indicating that a warmer climate may be fatal for the species if it is incapable of adapting or relocating. "We were surprised, however, by our finding that the Finnish populations were more successful in northern Norway than in Oulu — even more successful than the Norwegian variety there, in its home environment," says Postdoctoral Researcher Maria Hallfors from the Research Centre for Ecological Change at the Faculty of Biological and Environmental Sciences, University of Helsinki. "This indicates that global warming already affects this plant species. We can only speculate how many other species are suffering from changes to their environment, if they, too, are unable to keep up with climate change," Hallfors says.... "Siberian primrose has no natural dispersal route further north. One way to help species like this to survive current and future challenges would be to relocate them, by human hand, further north. In other words, species could be protected by what is known as assisted migration," Hallfors contemplates.

  • "How to rebuild California forests, with climate in mind" - by Ula Chrobak, 16 December 2020, Knowable Magazine.
    EXCERPTS: ... As foresters, ecologists and plant geneticists refine which seeds to plant to build climate-resilient forests, some scientists urge caution about importing seedlings from elsewhere. [Bruce] Baldwin, the evolutionary biologist, acknowledges that replanters have improved their methods in recent years by more carefully considering their seed sources, but he's skeptical of assisting trees in migrating to cooler elevations. "There's been a lack of appreciation for the potential downsides of some of that activity," he says.... Introducing new trees from populations that aren't next door on the seed map is still taboo among US agencies that oversee public lands. In [Emily] Moran's experiments in the Sierra and Tahoe national forests and Sequoia National Park — where the planted trees came from all over the state, not just right downhill — officials have required that she return and remove the trees before they fully mature and shed any seeds.... In Canada, however, forest officials have already changed their guidelines such that silviculturists are instructed to pick seeds suitable for a future warmer climate, rather than replanting with local seeds. That includes even shifting the species mix toward tree types better suited to a changing climate.... "Trees don't walk, and we are shifting the climate faster than it appears to have shifted in a long time," says [Malcolm] North. "It's incumbent on us to start researching and experimenting."
  • "Avalonia project (Connecticut) looks to prepare forest for the future" - by Judy Benson, 17 December 2020, U Conn press release.
    EXCERPTS: ... "We want to increase the resilience of the forest and maintain the water quality filtration services it provides to Long Island Sound," said Juliana Barrett, coastal habitat specialist for Connecticut Sea Grant. "We're trying to plant the right trees for the right time." Owned by the Avalonia Land Conservancy and popular with hikers and bird watchers, sections of the forest became unsafe over the last decade due to large numbers of diseased and storm-damaged trees. That prompted the land trust to contract with Hull Forest Products to do selective logging in 2019 that left open areas that will now be the subject of a joint project between Avalonia and CT Sea Grant.... Barrett said the project is one of the first of its kind in Connecticut that incorporates climate change projections and assisted migration techniques for plants better adapted to future conditions. ... "We're going to try some species at the edge of their limits in Connecticut that, based on climate change projections, we think will do well," Barrett said.... These could include loblolly pine, tulip poplar, sweetgum and others more common in the mid-Atlantic region.
        ... The education component will consist of a series of four webinars on topics relevant to the project, including the history of New England forests and the carbon sequestration services they provide. The series is intended for municipal officials, land trust officials, forest landowners and the general public. In addition, a two-day workshop on guiding principles for coastal forest resilience in the Long Island Sound region will be offered specifically for municipal officials, resource managers, land trust officials, forest landowners and students. An accompanying fact sheet will be developed and published.


  • "Cross-jurisdictional insights from forest practitioners on novel climate-adaptive options for Canada's forests" - by Guillaume Peterson St-Laurent, Robert Kozak, and Shannon Hagerman, 5 January 2021, Regional Environmental Change.
    ABSTRACT: Forest practitioners play a key role in the development and implementation of novel interventions to respond to climate change in forests. However, little is known about how this group perceives climate change adaptation, let alone novel interventions. Understanding how practitioners evaluate and weigh the risks of climate change for forests, their levels and patterns of support for different climate-adaptive interventions, and their views about key factors to consider in implementing novel interventions, is essential for understanding how and why different forest jurisdictions are responding to climate change. Using a comparative case study of three Canadian provinces — Alberta, British Columbia, and Quebec — we use an online survey to quantify the judgments of forest practitioners (n = 531) as above. We focus on assisted migration (AM), a climate-adaptive reforestation option that involves the intentional movement of tree species to more suitable areas within or outside of natural range based on climatic projections and genomic information. Overall, we find widespread support for AM across all three provinces, with more support for AM within as compared with outside of natural range. The central challenges of implementing AM are primarily perceived to be technical (e.g., climate projections, ecological data, and modeling), with other factors (e.g., economic viability, capacity and willingness of the forest sector, public opinion) being of secondary concern. While perceptions and patterns of support vary by province, our findings suggest that forest practitioners are embracing novel reforestation practices such as AM in response to new realities brought about by climate change.

  • "R-R-T (resistance-resilience-transformation) typology reveals differential conservation approaches across ecosystems and time" - by Guillaume Peterson St-Laurent, Lauren E. Oakes, Molly Cross, and Shannon Hagerman, 14 January 2021, Nature - Communications Biology.
    ABSTRACT: Conservation practices during the first decade of the millennium predominantly focused on resisting changes and maintaining historical or current conditions, but ever-increasing impacts from climate change have highlighted the need for transformative action. However, little empirical evidence exists on what kinds of conservation actions aimed specifically at climate change adaptation are being implemented in practice, let alone how transformative these actions are. In response, we propose and trial a novel typology — the R-R-T scale, which improves on existing concepts of Resistance, Resilience, and Transformation — that enables the practical application of contested terms and the empirical assessment of whether and to what extent a shift toward transformative action is occurring. When applying the R-R-T scale to a case study of 104 adaptation projects funded since 2011, we find a trend towards transformation that varies across ecosystems. Our results reveal that perceptions about the acceptance of novel interventions in principle are beginning to be expressed in practice.

    EXCERPTS: ... Novel conservation actions and objectives aimed specifically at helping ecosystems adapt to the accumulating impacts of climate change (hereafter "conservation adaptation") have gained increasing attention. For example, transformative actions such as species translocation and objective setting by triage principles that were not long ago eschewed by most conservation scientists, and declared by practitioners and policy-makers as anathema to the practice of conservation, are today increasingly highlighted as necessary components of conservation adaptation. At the core of arguments for a more future-looking, transformative approach are concerns that contemporary conservation practices — even those informed by climate change — remain focused on actions and objectives to preserve historic conditions rather than facilitating transitions to anticipated new ecological and climatic regimes.
         ... This study takes a critical first step towards answering the question of whether, and to what extent, a shift toward transformative actions is occurring within the field of conservation adaptation. We make two novel contributions. First, we develop a typology of adaptation actions that reduces linguistic uncertainty and supports subsequent, widespread empirical analysis of adaptation trends in the field of conservation practice. Second, we trial the typology by applying it to a case study of 104 adaptation projects funded by the Wildlife Conservation Society (WCS) Climate Adaptation Fund (hereafter "CAF projects") in the United States to assess potentially emerging trends in the field of conservation adaptation between 2011 and 2019. This study addresses two questions in relation to the CAF projects dataset: (1) What types of adaptation actions have been funded and implemented between 2011-2019, and (2) To what extent have adaptation actions changed over time, and do they vary across ecosystems in which they are implemented?
         ... The last three levels represent different degrees of transformation. Autonomous transformation describes actions aimed at allowing for changes without actively shaping the projected transformation, which is equivalent to the RAD framework's Accept category. Directed and accelerated transformation aim to drive a shift towards future projected conditions; they are distinguished by the relative speed at which transformation occurs. Directed transformation encompasses actions delivering the first few steps of the anticipated transformation, such as translocating species into areas that are expected to be suitable in the future and are also located within their current native range, but outside of their genetic range (e.g., assisted gene flow). In contrast, accelerated transformation denotes a jumpstart to the anticipated conditions, such as translocating species to areas that are anticipated to be climatically suitable in the distant future and that are located outside of their current native range (e.g., assisted range expansion or assisted colonization).
         Overall, we find that CAF projects funded prior to 2016 focused primarily on the resistance-resilience end of the R-R-T scale, and those implemented afterwards were more likely to involve transformation. The types of approaches differ across ecosystems with more resistance projects occurring in deserts, grasslands and savannahs, and inland aquatic ecosystems, and more transformative projects in forest, coastal aquatic, and urban/suburban ecosystems.
         ... Conservation in forested systems appears to be at the leading edge for the application of transformative actions (64% of projects), particularly in the form of assisted migration within current natural range. Most directed and accelerated transformation projects in other ecosystems (e.g., inland riparian, grasslands and savanna) also involved components of assisted migration of trees or plants (exceptions include, for instance, the assisted migration of seabird species in Hawaii). This finding is reflective of previous research that identified plants as a susceptible taxon for assisted migration because it involves a lower risk of intracontinental invasion due to dispersal constraints.
         ... In its early years the Fund prohibited any project proposal that involved the movement of species outside of their current natural range. The slow occurrence of accelerated transformation projects since 2016 — the year when assisted range expansion was deemed acceptable by the Fund — suggests a potential upsurge of such projects in the coming years. These funding rules offer additional evidence of the shift in perspective from resistance to transformation and the more widespread acceptance of controversial transformative projects (e.g., assisted migration).... Our study provides empirical evidence of paradigm shift, as practitioners and funders begin to move in this direction.

  • "Assisted Migration Field Tests in Canada and Mexico: Lessons, Limitations, and Challenges" - by Cuauhtemoc Saenz-Romero, Greg O'Neill, Sally N. Aitken, and Roberto Lindig-Cisneros, January 2021, Forests.
    ABSTRACT: Assisted migration of forest tree populations through reforestation and restoration is a climate change adaptation strategy under consideration in many jurisdictions. Matching climates in which seed sources evolved with near future climates projected for plantation sites should help reduce maladaptation and increase plantation health and productivity. For threatened tree species, assisted migration outside of the species range could help avert extinction. Here, we examine lessons, limitations, and challenges of assisted migration through the lens of three assisted migration field trials of conifers in Canada and Mexico: Pinus albicaulis Engelm., an endangered subalpine tree species in the mountains of western North America; the Picea glauca (Moench) Voss X P. engelmannii Parry X Engelm hybrid complex, of great economic and ecological importance in western Canada, and Abies religiosa, a tree species that provides overwintering sites for the monarch butterfly. We conclude that: (a) negative impacts of climate change on productivity of Picea glauca X P. engelmannii may be mitigated by planting seed sources from locations that are 3 °C mean coldest month temperature warmer than the plantation; (b) it is possible to establish Pinus albicaulis outside of its current natural distribution at sites that have climates that are within the species' modelled historic climatic niche, although developing disease-resistant trees through selective breeding is a higher priority in the short term; (c) Abies religiosa performs well when moved 400 m upward in elevation and local shrubs (such as Baccharis conferta Kunth) are used as nurse plants; (d) new assisted migration field trials that contain populations from a wide range of climates tested in multiple disparate climates are needed, despite the costs; and (e) where naturalization of a migrated tree species in recipient ecosystem is viewed as undesirable, the invasive potential of the tree species should be assessed prior to large scale establishment, and stands should be monitored regularly following establishment.

    EXCERPTS: Even the most critical views against assisted migration concede that more field experimental evidence of assisted migration is needed. We agree that the risks and benefits of assisted migration need to be informed with more experimental evidence, particularly with well-designed provenance trials. Here, we present three case studies of field experiments established to evaluate assisted migration in forest trees. Two of these studies pertain to tree species of conservation concern (Pinus albicaulis (whitebark pine) in Canada and Abies religiosa (Sacred fir) in Mexico) and the other deal with economically important tree species (Picea glauca X engelmannii hybrid complex known as interior spruce, in Canada). These examples were selected as examples of assisted migration both within and outside the species' native geographic range.... While assisted migration outside of range may be the form of assisted migration most commonly considered by the general public, and indeed by many forest scientists and foresters, the wide natural distribution of most North American tree species combined with the relatively short geographic and climate distances actually proposed for assisted migration suggest that most AM in forestry will likely take the form of assisted migration within range.... The optimum migration distance should also consider climate change during the lifespan of a plantation by weighing the risk of maladaptation during seedling establishment with the risk of maladaptation towards the end of a plantation's lifespan. A recently implemented assisted migration system in BC adopted the projected climate at one quarter of the plantation's expected lifespan as the adaptation target date.

  • "Can long-lived species keep pace with climate change? Evidence of local persistence potential in a widespread conifer" [Lodgepole Pine] - by Sarah M. Bisbing et al., February 2021, Diversity and Distributions.

       ABSTRACT excerpts: ... Here, we use Pinus contorta, one of the most widely distributed conifers in North America, to evaluate the influence of landscape heterogeneity on genetic structure as well as the magnitude of local adaptation versus phenotypic plasticity in a widespread tree species.... Survival of two of the three populations tested was consistent with patterns of local adaptation documented for P. contorta, while growth was indicative of plasticity for populations grown under novel conditions and suggesting that some populations are not currently occupying their climatic optimum.

    DISCUSSION excerpts: ... We also observed evidence of high phenotypic plasticity in all populations, and this response, despite local adaptation, is likely to promote local population persistence in P. contorta and other widely distributed tree species (Alberto et al., 2013). With an estimated 12 generations required for Pinus species to adapt to projected future conditions (Rehfeldt et al., 2001, 2002), evolutionary change is unlikely to match the pace of climate change, and phenotypic plasticity may allow population persistence under a wide range of future local conditions. Previous work found that plasticity in P. contorta growth potential was highest for populations from warmer environments, whereas cold-hardy populations were limited in growth plasticity but exhibited higher survival in colder environments (Rehfeldt et al., 2018). Population response in our gardens was consistent with these expectations: murrayana from the warm, dry Sierra Nevada had low survival in the cold, dry latifolia garden but exceptional growth rates across all environments, while latifolia had high survival at home and a limited growth response elsewhere. This ability of P. contorta genotypes to be plastic in their response to environmental heterogeneity may provide the foundation for persistence potential by buffering local populations from negative selection and giving this long-lived, slow-to-migrate tree species more time to adapt to novel local conditions (Alberto et al., 2013; Crispo, 2008).

    ... Although plasticity may provide populations time to adapt, it is concerning that many populations of P. contorta and other conifers of western North America already lag behind their climatic optimu (Gray & Hamann, 2013; Johnstone & Chapin, 2003). Climate change projections indicate a decline in P. contorta suitable habitat across much of the species range by 2080 (Coops & Waring, 2011; Oney et al., 2013), and productivity and growth are expected to decline at lower latitudes and elevations in the near future (Rehfeldt et al., 2001; Wang et al., 2006).... Similar mismatches to contemporary climate were recently identified in Pinus ponderosa (Mart�nez-Berdeja et al., 2019) and Quercus lobata (Browne et al., 2019) and interpreted as evidence of environmental change that exceeds the pace of evolutionary change (i.e., adaptational lag; Matyas, 1994). In these species, populations from warmer, drier climates had the highest growth potential when grown in cooler or wetter conditions, suggesting a mismatch to current climate and high vulnerability to ongoing warming and drying.

    CONCLUSIONS: Our findings suggest that P. contorta populations likely have high persistence potential via phenotypic plasticity and high genetic variability. However, geographically-based genetic substructure in some portions of the species' range as well as complete mortality of non-local populations in our most water-limited garden also indicate that some populations may be vulnerable to local maladaptation and extirpation with rapid climate change. Management of conifers is already incorporating assisted migration as part of a conservation strategy for maintaining viable populations of these long-lived species (e.g., O'Neill et al., 2008; Young et al., 2020), and our results suggest that such efforts may be warranted for vulnerable populations, complementing the natural processes of high gene flow and local adaptation within widespread conifers.

  • "The potential for using rare, native species in reforestation — A case study of yews (Taxaceae) in China" - by Ditte Arp Jensen et al., 15 February 2021, Forest Ecology and Management.
    CONCLUSIONS: In this study, we show that there is substantial quantitative potential of using Taxus cuspidata, Torreya grandis, as well as likely other native Taxaceae species, in reforestation in China. Based on our results and on findings from the scientific literature, we argue that Taxaceae species can contribute to generate structurally complex stands of increased value for biodiversity and increased stability, hereby also contributing to climate change mitigation as well as other important ecosystem services. Further, using rare Taxaceae species in reforestation will also help conserve these rare species in a changing future.

    EXCERPTS: ... Here, we present a species distribution modelling (SDM) framework for assessing the potential use and integration of native species into local forest restoration projects. We chose two species from the Taxaceae family for our case study since they represent species that are usually under-used in reforestation, but that can potentially bring both ecologically and culturally important functions to a restored ecosystem. We address the following questions in the assessment: 1) Which areas of China are climatically suitable and available for reforestation using Torreya grandis and Taxus cuspidata? 2) How is the local-scale natural occurrence of these species affected by environmental factors, and what are the implications for their use in restoration?
         ... Species of the yew family (Taxaceae) are rarely used in reforestation. The yew family encompasses six extant genera worldwide, four of which are represented in China with eleven species where of five is endemic (Fang, Wang and Tang, 2011). Several Taxaceae genera have restricted natural distributions, e.g. most of the Chinese Taxaceae species are endemic to small regions within China or between China and neighboring countries, and many species are listed as either vulnerable or endangered (IUCN Red List). Further, many Taxaceae species are threatened especially by human factors such as collection of plant material for medicinal uses and habitat destruction, as well as climatic changes (Cope, 1998; Qin et al., 2017). Taxaceae species have flat needle-like leaves, and are mostly slow-growing, dioecious trees/shrubs (Cope, 1998). Uniquely among conifers, they produce solitary ovules surrounded by a fleshy aril, and hence have value for frugivorous animals (Cope, 1998; Li et al., 2015; Tsuji and Morimoto, 2016). Although Taxaceae species are rarely planted as part of forest restoration efforts, several conservation projects to protect threatened populations of Taxaceae species exist worldwide (Iszkulo, 2001; Kwit, Horvitz and Platt, 2004; Shi, Bai and Lu, 2010; Qu, Wang and Zhang, 2018). Because of their long-lived, shade-tolerant nature and low stature, Taxaceae species have the potential to provide ecosystem services in terms of adding to the structural complexity of the restored area by creating stable patches with an evergreen, middle-story layer.
         Torreya grandis is an evergreen conifer tree species native to the subtropical monsoon regions of east-central China. It grows most often as an understorey tree at elevations between 200 and 1400 m a.s.l. reaching up to 25 m tall and producing fleshy, edible seed cones (Flora of China). A variant of the species, To. grandis cv. Merrilli, is cultivated on a large scale and the aril and seeds are used for making essential oil and for human consumption (Feng et al., 2011; He et al., 2016; Yu et al., 2016; Chen and Jin, 2019). Taxus cuspidata is a small evergreen conifer tree native to northeast China, east Russia, Korea and Japan. The species often grows in cold, humid forests at elevations of 500-1000 m a.s.l. as an understorey tree that reaches a maximum height of 20 m (Flora of China). It produces red, fleshy seed cones that are edible (aril only), while the foliage, bark and seeds contain the poisonous alkaloids called taxines (like all members of the Taxus genus) (Russin et al., 1995; Thomas and Polwart, 2003). The wood is used for manufacturing of furniture and as carving material, while the heartwood yields a red dye (Flora of China).

  • "U.S. conservation translocations: Over a century of intended consequences" - by Ben J Novak et al., March 2021, Conservation Science and Practice.
    Note by editor, Connie Barlow: Although assisted migration in response to climate change is not mentioned in this report, one sentence does speak to the risk of a translocated listed species becoming invasive within the recipient ecosystem: "None of the 608 total invasive species established in the U.S. and its territories as reported in the GISD [Global Invasive Species Database] resulted from conservation translocations." I highlight this quote because the risk of invasiveness was one of two risks stated at the onset of debate (in 2004) over assisted migration of the glacial relict Florida Torreya — and as of 2024 has not officially been set aside. The other risk stated since the beginning was to ensure that translocation into different climate zones would not prove to be a waste of funds, owing to climate-based failure. It is noteworthy that the citizen network of Torreya Guardians, relying entirely on their own money for moving seeds by mail or private vehicle, called upon no government, foundation, or NGO to help with their expenses.
  • "To Save Giant Sequoia Trees, Maybe It's Time to Plant Backups" - by Kevin Webb, 15 March 2021, State of the Planet: Blog of Earth Institute, Columbia University.
    EXCERPTS: "Because of their slow dispersal, long time to reproduce, scientific value, and sheer charisma, sequoias are ideal test subjects for how responsible assisted migration might work. Sites would be further north along the Sierras, where sequoias might have spread with longer time horizons and fewer manmade obstacles. Groves could be planted with genetically diverse seed stock, with enough seeds planted to allow natural selection to work. Partnered institutions and organizations would be responsible for ongoing study and monitoring for adverse consequences. If successful, methodologies could hopefully be re-used for many species facing similar fates. Even if groves throughout California were lost, there would then still be living, thriving trees whose seeds could someday repopulate their original territory.
         Ultimately, I'm drawn to considering assisted migration because it is active and optimistic, when so much of conservation is necessarily about just slowing damage. Climate change is the mother of all collective action problems, where individuals' powerlessness can manifest as very real climate grief. Meanwhile, anyone with a yard or access to a park can advocate for species figuring out how to survive. If done responsibly, welcoming some species into new, relatively nearby homes would be an act of faith that there will be a place for the array of life that calls Earth home. It's faith that humans can be forces for more than destruction."
    "Climatic criteria for successful introduction of Quercus species identified by use of Arboretum data", by Corrie Lynn Madsen et al., March 2021, in Forestry.
    Climate change is projected to have a major influence on forest tree populations and composition. Translocation of species outside their historic range has been suggested to maintain healthy forests and tree species. The introduction of exotic species into botanical gardens and arboretums worldwide demonstrates the ability of many trees to grow outside their natural habitat and may play an important part in avoiding climate driven extinction if grown in a matching climate. However, it remains to be determined which climatic factors are the most important predictors of climatic match. In this study we use information from the arboretum in Horsholm, Denmark, to analyse differences in performance of translocated Oak (Quercus) and show how data from tree collections can be used to predict success of assisted migration.
         ... Here, we propose a new statistical approach to study assisted migration specifically by using empirical data from arboreta. In this paper, we use information from the arboretum in Horsholm, Denmark, to analyse differences in seed source performance. Oak (Quercus) is used as a model genus since Oaks are considered important forest forming trees in the Northern Hemisphere and have great global ecological, scientific and economic importance (Simeone et al., 2013). Differences in performance are related to climate conditions at provenance origin and thereby interpreted across environmental gradients. Ultimately, our goal is to clarify whether data collected from arboreta can be used for scientific study to identify which climatic variables are most important for predicting growth and survival when translocating species outside their natural distribution.... In Europe and the Mediterranean region, Quercus comprises around 30 species (Govaerts and Frodin, 1998; Kubitzki, 1993), whereas Denmark only holds two naturally occurring species, Pedunculate oak (Q. robur L.) and Sessile oak (Quercus petraea Mattuschka Liebl.). The Horsholm arboretum currently holds 113 (including 18 grafted) trees of the genus with representatives of 27 species (three species only as graftings), collected in North America, Europe and Asia.... Diameter growth rates varied between 0.15 and 0.95 cm y-1. Some non-native Quercus species were at par with the two native species found in Denmark, Pedunculate oak and Sessile oak (Supplementary Table S2). This included six North American species, white oak (Q. alba L.), swamp white oak (Q. bicolor Willd.), Hill's oak (Q. ellipsoidalis E.J. Hill), chestnut oak (Q. montana Willd.), Pin oak (Q. palustris Munchh.) and black oak (Q. velutina Lam.), from sections Quercus and Lobatae, and Turkey oak (Q. cerris L.) native to SE Europe and Turkey from the Quercus section. None of the East Asian origins showed fast growth.... Climatic extremes occurring at a critical stage in the life of seedlings may also have removed species able to survive as a tree, and conversely, watering of young plants during the establishment phase may have given them an unnatural advantage. Limitations are illustrated by the mortality of some Danish accessions (Figure 1). Assessing individual species based on a single introduction is therefore questionable. In an assessment of the role of botanical gardens in research on climate change, Primack and Miller-Rushing (2009) emphasized the advantageous features and resources available at botanical gardens in climate change research as being primarily due to controlled growing conditions and living collections with broad taxonomic representation. Yet, the aggregated data presented here demonstrates that even with a relatively restricted data set, interesting patterns of adaptation can be extracted. The analysis applied a meta-type approach, where focus is not on the individual tree or species, but rather on the performance of the whole assembly of introductions. Although our analyses can give probabilities for performance of individual species or origins, the major advantages of the approach seem to be identification of areas with potential homologous climates for trees, and help in identifying the underlying climatic factors.
         CONCLUSION: ... We find that arboretum data contain biogeographic information that may help interpret factors involved in climatic adaptation, and assist in selecting suitable source areas for assisted migration. The full potentials can only be realized, however, if data from several arboreta are combined. Here we determined criteria for successful migration under current conditions, but what will they be under future conditions? Establishing a network of collections ('metacollections' as coined by Dosmann 2006) across Europe or the world would make it possible to expand the scope of analyses considerably by verifying whether the same parameters are decisive for success under different conditions, and by allowing more detailed studies of individual species or genera. This could potentially lead to a new understanding of assisted migration under climate change.

    • March 2021 - "Ecological risk assessment of managed relocation as a climate change adaptation strategy" - by Aviv Karasov-Olson et al., report to and published by U.S. National Park Service, 113 pp. Note: Two co-authors are also authors of principle papers on this issue in the early years: Mark W. Schwartz and Jessica J Hellmann. The report includes 4 case studies: Bull Trout, Karner Blue Butterfly, Giant Sequoia, and Pitcher's Thistle.

    EXCERPTS: Changing climate and introduced species are placing an increasing number of species at risk of extinction. Increasing extinction risk is increasing calls to protect species by relocating, or translocating, them to locations with more favorable biotic or climatic conditions. Managed relocation, or assisted migration, of species entails risks to both the conservation target organisms being moved as well as the recipient ecosystems into which they are moved.... These protocols provide guidance for qualitative ecological risk assessment to inform management decisions regarding proposed movements of populations or species beyond their historical range as a conservation management response to climate change or invasive species. The protocols provided here are not designed to answer the question "Should management move a species?" This subjective question must be answered by the decision-maker. Protocol completion informs that decision by formalizing a risk analysis and risk characterization. The purpose of assessing risk is not to preclude such actions by promoting an environment of risk aversion. Rather, these protocols inform risk management by assisting the user in evaluating the risk of causing harm by either taking or not taking a managed relocation action and balancing this risk against perceived benefits of the proposed action.
         ... We adopted the premise that risk decisions are inherently subjective and that different aspects of risk (e.g., the risk of a moved species introducing a novel pathogen to an ecosystem, the risk of unwanted evolution in the moved species) are non-additive. Hence, our strategy is designed to encourage managers to think broadly and comprehensively about risk in order to make the best possible decision given alternate opposing risks (i.e., the risk of extinction versus the risk of causing unintended harm to other species and ecosystems in the process of trying to save a species).... These protocols are tools to guide evaluation of the ecological risk of species managed relocation as part of planning and decision making. The protocols do not address existing, or proposed, policies regarding managed relocation (or assisted migration) as a natural resource management strategy.... We treat the term 'managed relocation' as similar to and encompassing 'assisted migration, 'assisted dispersal', and 'ecological replacement, and as a subset of the broader set of actions known as 'conservation translocations' (McCormack 2018).
         The intended audiences for this risk assessment strategy are biologists, ecologists, and managers responsible for decisions regarding managed relocations involving natural areas, such as federal and state parks and protected areas. We envision two primary scenarios in which readers can use these protocols to consider managed relocation. First, we address cases where the historical range of a target becomes unsuitable, and the target might not be able to disperse on its own to newly suitable sites. Here, the intended use is for considering managed relocations in response to threats to targets where climate change, at least in part, increases extirpation risk. Second, we seek to inform cases where changing environmental conditions are compromising an existing ecosystem. In this case the intended use is for considering managed relocations aiming to recover or retain ecosystem functionality in the recipient ecosystem, to foster longer term conservation goals in light of the dynamics on the landscape (e.g., ecological replacement).

    Note: In July 2021 the same set of authors published a scholarly paper on this same project: "Co-development of a risk assessment strategy for managed relocation", Ecological Solutions and Evidence.

    • March 2021 - "Climatic criteria for successful introduction of Quercus species identified by use of Arboretum data" - by Corrie Lynne Madsen et al., Forestry, Oxford Academic, Institute of Chartered Foresters.

    ABSTRACT EXCERPT: ... In this study we use information from the arboretum in Horsholm, Denmark, to analyse differences in performance of translocated Oak (Quercus) and show how data from tree collections can be used to predict success of assisted migration. Our data included archive lists of georeferenced Northern hemisphere introductions of Quercus, and assessments of their survival and growth rates in nursery and the Horsholm arboretum.... The study demonstrates an approach to use historical data collected from arboreta and botanical gardens in climate change research. This new approach can provide useful information in relation to assisted migration for an array of poorly investigated species where this may be the only source of information.

    EDITOR'S NOTE: This paper begins with an excellent REVIEW of key papers and concepts, mostly drawn from North American foresters, including Aitken et al. 2008, Iverson 2004, Rehfeldt et al. 1999, Davis 1989, and Saenz-Romero et al. 2017 — which compare distance estimates of natural tree dispersal rates v. cited estimates of the speed of future range shifts.

    EXCERPTS: ... Here, lessons learned from unsuccessful planting can also improve knowledge about phenotypic plasticity at the species level — how sensitive are species to modification in their climatic growth conditions? To what extent are we able to understand and predict the success of species moved by assisted migration?... Ultimately, our goal is to clarify whether data collected from arboreta can be used for scientific study to identify which climatic variables are most important for predicting growth and survival when translocating species outside their natural distribution.... Since the establishment in 1936, 27 species of known origin from the genus Quercus, corresponding to 62 accessions from four continents, were tested in the arboretum (Figure 1).... Some non-native Quercus species were at par with the two native species found in Denmark, Pedunculate oak and Sessile oak (Supplementary Table S2). This included six North American species, white oak (Q. alba L.), swamp white oak (Q. bicolor Willd.), Hill�s oak (Q. ellipsoidalis E.J. Hill), chestnut oak (Q. montana Willd.), Pin oak (Q. palustris M�nchh.) and black oak (Q. velutina Lam.), from sections Quercus and Lobatae, and Turkey oak (Q. cerris L.) native to SE Europe and Turkey from the Quercus section. None of the East Asian origins showed fast growth.... Height growth rates varied between 10 and 44 cm y-1 . Several non-native species had a high mean height growth rate (Supplementary Table S2). These included Scarlet oak (Quercus coccinea M�nchh.), Hill's oak, Pin oak, Shumard's oak (Quercus shumardii Buckley), Black oak and also Turkey oak.... Only one bioclimatic variable, bio15 (precipitation seasonality), was significant across all dependent variables affecting both survival and growth rates negatively. High precipitation seasonality was associated with lower chance of survival and growth rates. ... Finally, with respect to fruiting, seven of the surviving species so far were observed to bear fruits (Supplementary Table S2).

    DISCUSSION EXCERPTS: Data from the Horsholm arboretum (and other arboreta) are seen from a traditional experimental point of view marred by lack of repetitions, imbalances in the data, variations in microclimate across the site and sometimes incomplete information about the origin. We assume that horticultural practices have been fairly constant but cannot rule out certain inconsistencies. Climatic extremes occurring at a critical stage in the life of seedlings may also have removed species able to survive as a tree, and conversely, watering of young plants during the establishment phase may have given them an unnatural advantage. Limitations are illustrated by the mortality of some Danish accessions (Figure 1). Assessing individual species based on a single introduction is therefore questionable. In an assessment of the role of botanical gardens in research on climate change, Primack and Miller-Rushing (2009) emphasized the advantageous features and resources available at botanical gardens in climate change research as being primarily due to controlled growing conditions and living collections with broad taxonomic representation. Yet, the aggregated data presented here demonstrates that even with a relatively restricted data set, interesting patterns of adaptation can be extracted. The analysis applied a meta-type approach, where focus is not on the individual tree or species, but rather on the performance of the whole assembly of introductions. Although our analyses can give probabilities for performance of individual species or origins, the major advantages of the approach seem to be identification of areas with potential homologous climates for trees, and help in identifying the underlying climatic factors.... Species showing fast growth were distributed across sections and across the North American and Eurasian continents, with the native Pendunculate oak and Sessile oak performing at par with species such as swamp white oak, Hill's oak pin oak and Turkey oak. There are few comparisons of performance of broader ranges of Quercus species, but Sanders et al. (2013) found that three exotic species marginally outperformed the native Pedunculate oak and Sessile oak in England. The only geographical signals in our study was the failure of southern introductions (Mexico and Morocco) and the slow growth of Asian introductions.
         ... Modelling of climate effects on species mainly focusses on range contraction or expansion within the natural distribution area. Although long-distance assisted migration is considered controversial, it seems reasonable to identify potential successful long-distance translocations to counteract the expected speed of climate changes (Aitken et al., 2008). Arboreta and botanical gardens have already started this line of research with detailed records of species collected from other countries and continents (Primack and Miller-Rushing, 2009), which could be expanded to show the potential for survival and growth, such as this pilot study has demonstrated. If our data for Quercus can be extrapolated it suggests that transfers can be made to warmer climates, but that trees from the genus will be poorly adapted when transferred to areas with lesser rainfall.
         ... A basic assumption in species distribution modelling is that climate is the main limiting factor for species distributions, and species distribution models are usually based on presence or presence/absence data (e.g. Dyderski et al. 2018). To the extent that species distribution is limited by dispersal or competition, and not by climatic extremes, this may result in bias when the potential natural distributions are mapped. Recently it has even been questioned whether species distribution models ignore important bioclimatic variables (Gardner et al. 2019). In that respect, tree collections and arboreta provide experimental evidence of the climatic suitability outside the natural range (Booth, 2015), and hence may verify variables used in distribution modelling.
         It is our opinion that data from tree collections have so far been underutilized and we suggest that they possess a wide range of information needed to understand tree performance under future climates. The inclusion of arboretum data may reduce the effect of non-climatic constraints and offer tested and proven data for identifying climatic matches. Including additional factors such as production of fertile seed and possibilities for natural regeneration would be an additional asset to further improve models of potential distributions of forest species.

    CONCLUSION: We find that arboretum data contain biogeographic information that may help interpret factors involved in climatic adaptation, and assist in selecting suitable source areas for assisted migration. The full potentials can only be realized, however, if data from several arboreta are combined. Here we determined criteria for successful migration under current conditions, but what will they be under future conditions? Establishing a network of collections ('metacollections' as coined by Dosmann 2006) across Europe or the world would make it possible to expand the scope of analyses considerably by verifying whether the same parameters are decisive for success under different conditions, and by allowing more detailed studies of individual species or genera. This could potentially lead to a new understanding of assisted migration under climate change.

    • 22 April 2021 - "Earth Day 2021: Why reforestation is a crucial part of saving the environment" - by Julia Jacobo, ABC NEWS.

    EXCERPTS: Climate change may be the focus of the environmental movement, but restoring the Earth, the theme of this year's Earth Day, will play a crucial role in keeping global temperatures down.... Reforestation is the top nature-based climate solution in the U.S., Brian Kittler told ABC News. Solomon Dobrowski, professor of landscape ecology at the University of Montana, believes that forests play a "pivotal role" in finding solutions for biodiversity and climate change.... Building brand new forests provides scientists with an opportunity to approach the replanting strategically, Burney said, describing the process as "climate-smart reforestation." Researchers have taken the idea of assisted migration — for example, planting a species of tree that is native to the area but sourcing the seed from a little farther south — to ensure that the forest will endure....
    • 22 April 2021 - POLICY FORUM, CONSERVATION: "Global policy for assisted colonization of species" - by Jedediah F. Brodie and seven coauthors (Lieberman, Moehrenschlager, Redford, Rodriguez, Schwartz, Seddon, and Watson), Science.
    NEED FOR GLOBAL POLICY NOW: Negotiations in advance of the 15th meeting of the Conference of the Parties to the Convention on Biological Diversity (CBD) in October 2021 will set the course of international conservation for the next several decades, providing a critical opportunity to harmonize policy and set priorities for species conservation and climate change adaptation. The CBD is the foundational intergovernmental agreement on biodiversity conservation and drives both government actions and donor priorities. However, the treaty itself and its existing strategic framework (the "Aichi targets") were agreed on some time ago (1992 and 2010, respectively) and so need to match advances in knowledge and evidence on the immediate and devastating impacts of climate change.

    EXCERPTS OF DOCUMENT BEHIND THE PAYWALL: ... To keep pace with changing conditions, many organisms that cannot adapt will either need to move poleward in latitude, upward in elevation, downward in water depth, or to refugial areas that might lie outside their current or historical indigenous ranges. For many species, these movements are stymied by human infrastructure and disturbance. Assisted colonization — the translocation and establishment, for conservation purposes, of populations of organisms outside their historical range — could facilitate species conservation by moving individuals of species that cannot disperse around these barriers, allowing them to escape from shrinking climate refugia and to establish populations in new locations that have the conditions needed for population persistence. But despite having been discussed by conservation scientists for decades, assisted colonization has been deployed for climate adaptation only rarely and often remains precluded by contradictory global policies. Private citizens in several countries, however, have been acting on their own to implement assisted colonization without guidance, oversight, or reporting. There is therefore a need for processes by which potential assisted-colonization projects could be planned, evaluated, implemented, regulated, and monitored within the framework of international treaties, intergovernmental organizations, and statutory bodies. The CBD has an opportunity to set global standards that countries can create policy on, implement, and report back on. We recommend that the CBD empower a technical committee toward creation of an assisted-colonization protocol that all countries could implement based on structured benefit-risk assessment.
         ... The underlying values, goals, risks, and potential benefits must be evaluated in a transparent decision framework in any assisted-colonization project. The records from such a framework will also allow practitioners to learn from other projects, improving the efficacy of assisted colonization over time, thereby increasing the probability of success.
         ... The need for policy harmonization is especially acute for species that are "extinct in the wild," which have increased extinction risk but often cannot be returned to their historic ranges because conditions there are no longer suitable. Proof of this urgency was shown in November 2020, when members of the IUCN adopted a motion to improve the recovery of "extinct in the wild" species, with the support of 95% of government members voting and 99% of nongovernmental organizations voting. This included a call to "...recognize the role of populations outside historic ranges resulting from assisted colonization" (IUCN motion 119/2020).

    CONCLUDING PARAGRAPH: The time is ripe for the global conservation community to initiate a formal evaluation of regulatory approaches for assisted colonization, along with regulatory guidance on its implementation. Ecological and social vetting and risk assessment in potential assisted-colonization projects are already likely to slow the process. Appropriate screening and analysis are essential but should not delay decision-making to the point where it is too late to achieve desired outcomes. It is essential to develop policies to confront these issues head-on so that existing conservation strategies do not become impediments through lack of forethought and planning.

    PHOTO CAPTION: this paper contains one photograph, which is a picture of Florida Torreya. Here is the caption: "Florida torreya (Torreya taxifolia) is a species native to Florida that is currently undergoing unregulated assisted colonization to other US states."

    NEWS STORY BY AAAS STAFF WRITER: "International Policy Guidance for Assisted Colonization of Species Needed", by Walter Beckwith, 30 April 2021.

    EXCERPTS: ... In a Policy Forum in the April 30 issue of Science, researchers argue that global policy guidance for the assisted colonization of species threatened by climate change is urgently needed. "Assisted colonization could be a critical tool in our toolbox for ameliorating the impacts of climate change on biodiversity, but it could also be dangerous if done wrong," said lead author Jedediah Brodie, an ecologist at the University of Montana. "We argue that the international community needs a clear and coherent framework by which assisted colonization projects can be evaluated, vetted, regulated and reported." Considering the current negotiations in advance of the meeting of the Conference of the Parties to the Convention on Biological Diversity in October 2021 — an event that will set the course of international conservation policy for many years to come — now is the time to set global standards and targets for assisted colonization, the researchers say.
         According to Brodie, the strategy is becoming increasingly important as the impacts of climate change become increasingly severe. However, despite having been a topic of discussion among conservation scientists for decades, assisted colonization remains a controversial conservation strategy and is often precluded by contradictory global policy. One of the main arguments against using assisted colonization is fears that translocated species would become invasive and cause irreversible damage to their newly introduced communities. This is a valid concern given humans' poor track record with invasive species thus far, said Brodie.
         But this hasn't stopped private citizen groups from acting on their own accord to implement assisted-colonization projects for species without guidance, oversight, or reporting. For example, over the last several years, a group of well-intentioned citizen scientists have been working to translocate the highly-threatened, Florida-native conifer species, Torreya taxifolia or "stinking cedar," to forests in North Carolina. "My sense is that unregulated assisted colonization efforts have been relatively benign, so far," said Brodie. "But humans have been moving species to new areas for other reasons for a long time, and sometimes with disastrous consequences."
         As it currently stands, the Convention on Biological Diversity (CBD) — the foundational international agreement concerning the conservation of Earth's biodiversity — does not recognize assisted colonization. What's more, the Convention's existing biodiversity goals, last negotiated in 2010, are contradictory regarding the issue.
         ... "The strategy is controversial because of concern about introducing new invasive species or just altering natural communities, concerns that may have slowed or stymied policy development and project implementation," said Brodie. "But if done right, with careful vetting and multi-stakeholder engagement, assisted colonization could be a very important way of preventing extinctions in the coming decades." ...
    NEWS STORY IN YALE E360: "Amid Climate Pressures, a Call for a Plan to Move Endangered Species", by Zach St. George, in Yale Environment 360, 19 May 2021.
    EXCERPTS: ... Three decades later, people are still arguing over whether the risk of moving species to more favorable conditions outweighs the risk of inaction. This debate has spawned hundreds of scientific papers, media reports, and even side debates, including over what to call the novel conservation practice (which, in this article, will be referred to as "assisted colonization"). It is a debate fueled less by differences of fact and more by differences of philosophy.
         ... Guidelines from the [global] Convention on Biological Diversity would also make more space for discussion, says Sarah Dalrymple, a Liverpool John Moores University plant ecologist, who helped draft both the IUCN and Scotland's managed relocation guidelines. She says the fierceness of the debate has made even discussing potential experiments difficult. An official policy, she says, would "allow people to feel more like they could explore the potential for assisted migration, without having to put the head above the parapet and risk being shot down."
         ... The debate over assisted colonization is evidence that many conservationists and biologists remain stuck in an old paradigm, in which any human intervention in nature is undesirable and fraught, says Cuauhtemoc Saenz-Romero, a forest geneticist at Universidad Michoacana de San Nicolas de Hidalgo. Saenz-Romero has conducted experiments planting Mexican pines and firs upslope of their natural range in the mountains of central Mexico (a project also designed to aid overwintering monarch butterflies) and aims to do the same with several Mexican spruces in the future. Many of his frequent scientific collaborators work in forestry. In that industry, he says, where future profits depend on foresters planting trees well-suited to the local conditions, assisted colonization is quickly becoming a matter of course. Saenz-Romero says it's time for conservationists to also take a pragmatic look at the practice.
         "Humans have disrupted the ecology of the entire planet," he says, raising the amount of carbon dioxide in the atmosphere to levels not seen for millions of years. Assisted colonization may be an extraordinary measure, he says, but in such times, "we have to look at extraordinary things."

    • MONTH 2021 - The State of Canada's Forests: Annual Report 2020, Natural Resources Canada.

    EDITOR'S NOTE - Canadian foresters present the importance of helping forests move poleward without ever using the standard terms in use by conservation biologists pondering whether and when to move threatened species. In the entire 88 pages, the term "assisted migration" appears only twice — and that entirely within the titles of papers in the citations section. "Assisted colonization, facilitated migration, and managed relocation" do not appear at all. One can surmise that not only is this a practical way to defuse debate, but because the emphasis is on retaining healthy forest canopy — irrespective of species identities — there is no reason to choose a term created in the context of concern about species-specific tree wellbeing.

       "...Traditionally, foresters have used local tree seed for planting seedlings, as local populations were generally thought to be best adapted to the climate conditions of the site. However, with a rapidly changing climate, these local populations may not be able to adapt quickly enough, and while well-established adult trees can often withstand increased stress, seedlings are highly vulnerable. If forest managers know which seeds and seedlings from the southern portion of the range would thrive in the changing northern conditions, they can strategically select the hardiest and best-adapted for planting."

    SEE ALSO the frightening news report of Canada's aggregate forests shifting already from carbon sink to source: "One of Canada's biggest carbon sinks is circling the drain", by Barry Saxifrage, 7 May 2021, Canada's National Observer.

    • 3 May 2021 - "As northern Michigan warms, scientists bring tree seedlings from the south", by Kelly House, The Bridge Michigan

    EXCERPT: On a blustery hillside near the tip of the mitten, Noah Jansen stooped to inspect the shagbark hickory saplings he spent months growing from seeds collected 250 miles south of here. It's not a species commonly found among the maple, birch, cedar and white pines of northern Michigan. But on this 311-acre property known as Ziibimijwang Farm, few of the newly planted seedlings are.
         Jansen and his colleagues at the Little Traverse Bay Band of Odawa Indians have planted thousands of trees since the tribe purchased the property in 2013, transforming it into a small-scale experiment in girding northern forests against climate change. Along with the shagbark and silver maple, there's black walnut commonly found in southern Michigan, sassafras and swamp white oak that typically ranges only as far north as mid Michigan, and a host of other species — about 30 in all — that Jansen hopes will become the feedstock for a diverse, climate-resilient forest. "I don't know which of these species are going to thrive in 50 or 100 years,� said Jansen, the tribe's conservationist. "So we cast the net broad and try to have something there that creates habitat for wildlife, sources of cultural significance for tribal members and areas to hunt and gather."
         ... Forests migrate at a speed of "feet per year," said David Price, who leads the Michigan Department of Natural Resources' forest planning and operations section, inching into new territory only as far as their acorns, whirligigs and pinecones will scatter. Fossil records provide a measuring stick: After the North American ice cap retreated and temperatures rose following the ice age, forest ranges shifted by about 31 miles per century. The ongoing climate crisis is outpacing that speed. U.S. Forest Service scientists estimated in 2018 that growing regions in the Northern Hemisphere will shift hundreds of miles northward by the end of this century if humans fail to curb greenhouse gas emissions.
         For Renee Dillard, those changes are personal. A member of the Little Traverse Bay Bands and renowned Anishinaabe natural fiber artist known for her intricate black ash baskets, Dillard had to stop harvesting ash in northern Michigan's swamps after the emerald ash borer decimated the population. She switched to other fiber, including cedar, dogbane, basswood and bullrush. But climate change threatens to push some of those species northward, too, and Dillard believes they'll eventually become scarce near the Little Traverse Bay Bands' land in the Northwestern Lower Peninsula. So she is experimenting with substitutes from further south. She keeps a stash of pawpaw seeds, and occasionally buries a few near her home in Harbor Springs, hoping they'll grow into the deciduous tree nicknamed "the Indiana banana" for its custardy, tropical-tasting fruit. But it's the fibrous bark Dillard is after.
         Jansen's tree migration project is aimed at facilitating this kind of cultural resilience. He has specifically chosen plants that could preserve tribal members' ability to hunt, gather and carry on cultural traditions: There's sassafras, a species with medicinal properties. And American plum, which can be harvested by humans or grazed by deer. As foliage on the forest canopy matures, tribal species managers hope to continue their efforts by filling in the understory with plants that can survive in the future climate.
    • May 2021 - "Beyond Planning Tools: Experiential Learning in Climate Adaptation Planning and Practices", by Kristen M. Schmitt, Todd A. Ontl, Stephen D. Handler, Maria K. Janowiak, Leslie A. Brandt, Patricia R. Butler-Leopold, P. Danielle Shannon, Courtney L. Peterson and Christopher W. Swanston, May 2021, Climate
    Editor's note: The term "assisted migration" first appeared in the conservation biology literature and applied to endangered species with small or relict ranges. It was also the conservation biology academics who soon thereafter proposed a replacement term "assisted colonization" — designed to emphasize an intent not just to help a species move in sync with a changing climate but to ensure that the species successfully establishes there. Later, "assisted colonization" came under fire as potentially (or actually) repulsive to citizens and professionals of Indigenous heritage in Australia (and North America). This history of how the terminology originated and shifted through time in academic publications is presented in detail (and with links) on this webpage posted by Connie Barlow in 2021: "Assisted Migration or Assisted Colonization: What's In a Name? (Chronological History of the Debate on Terminology)".
        The distinction between FORESTRY and CONSERVATION BIOLOGY researchers and practitioners thus is carried through in terminology: While conservation biologists focus on the wellbeing of a species (and usually, in papers, just one species at a time), foresters focus on a situated forest — the health of a place, and thus the emphasis is on forest management practices to maintain healthy ecosystem services and natural resource values during this century of rapidly shifting climate.
        A 2021 paper coauthored by academic and USDA forestry researchers exemplifies this terminology trend in forestry: "Beyond Planning Tools: Experiential Learning in Climate Adaptation Planning and Practices", by Kristen M. Schmitt, Todd A. Ontl, Stephen D. Handler, Maria K. Janowiak, Leslie A. Brandt, Patricia R. Butler-Leopold, P. Danielle Shannon, Courtney L. Peterson and Christopher W. Swanston, May 2021, Climate. Below is Table 3. Notice the terminology in the right-most column of "Select Adaptation Actions." Also notice that of the 5 projects shown (all within MICHIGAN), 3 are Indigenous communities and 2 are conservation land trusts.

    "Cities as hot stepping stones for tree migration", by Qiyao Han et al., Urban Sustainability, 27 May 2021.
        ABSTRACT: Cities around the world are promoting tree-planting initiatives to mitigate climate change. The potential of such efforts to assist tree migration has often been overlooked. Due to the urban heat island effect, cities could provide suitable climates for the establishment of outlier populations, serving as propagule sources for poleward tree migration.

    EXCERPT: As a response to recent climate warming, cities such as Philadelphia, Chicago, and London (Ontario, Canada) have already begun planting more southerly tree species on urban parks, streets, as well as other municipal lands. However, the potential of urban tree planting to assist species migration in a wider landscape has often been overlooked. Due to the urban heat island effect, cities are experiencing a preview of future climates for nearby rural areas, potentially offering a climatic condition suitable for the persistence of outlier populations at higher latitudes than their native ranges. The outlier populations in cities could serve as propagule sources for species' poleward migration under climate change. Moreover, since trees can cool their environment, planting trees in cities can slow the rate of warming, which in turn allows them to grow for decades to reach reproductive maturity for further expansion. Here, we discuss the potential of urban tree plantings to assist the poleward migration of forest trees in temperate and boreal regions. Emphasis is placed on the unique climatic condition that cities could provide for the establishment, growth, and expansion of outlier populations.
        ... The stress induced by rapid climate warming will be exacerbated by the negative effect of extreme weather events (e.g., heat waves, drought, floods, and storms), which constrain the establishment and spread of tree species. The consequent decoupling between climate shifts and species migrations may result in species extinction, as happened to a species of spruce, Picea critchfieldii, in eastern North America after the Last Glacial Maximum.
         Despite the pessimistic predictions, empirical studies of postglacial recolonization indicate that trees in boreal and temperate regions may not necessarily lag behind climate change, as species migration can be facilitated by the persistence of outlier populations in advance of their main ranges. Rapid range shifts of boreal and temperate trees occurred following the retreat of ice sheets after the last glacial period. Molecular evidence suggests that such range shifts were achieved by local dispersal from small, isolated populations occupying high-latitude microrefugia, where climates were favourable for their persistence outside of main ranges during the glacial period. A well-documented example is ice-free refugia in northern Scandinavia, which supported the survival and expansion of conifer trees after the Last Glacial Maximum. Recent models have also highlighted the favourable effects of outlier populations on poleward range shifts. The role of outlier populations in the past may have an analogy under future climate change, as outlier populations not only can occur naturally as relicts of past climates but also could result from anthropogenic planting. Even a small number of trees planted far beyond their native range limit can be sufficient to establish naturalized populations.
         URBAN HEAT ISLANDS AS STEPPING STONES. Cities are already ahead of their surroundings in terms of climate warming, therefore potentially offering suitable climate conditions for the establishment of outlier populations (Fig. 1). Urban areas tend to have higher temperatures than their surrounding rural areas as if a warmer city air lies in a "sea" of cooler rural air. This phenomenon has been commonly observed and investigated around the world, known as the urban heat island effect. Generally, the urban heat island effect is an "inadvertent" modification of local climates during urbanization.... In Baltimore, for example, urban�rural differences in air temperature are similar to projected climate changes over the next 50-100 years.... Planting outlier populations in urban heat islands is expected to provide a substantial head start on poleward range shifts.... It is, therefore, possible to shorten or even eliminate migration lags in tree species by planting outlier populations in cities.... An investigation of 357 European plant species showed that 73% of them have been moved into nurseries and gardens hundreds or even thousands of kilometres north of their natural range limits. In the eastern United States, southern species planted in northern urban areas as ornamental plants are expected to speed the process of tree migration to a rate of 1 km per year.... The process of range expansion can be supported by urban green spaces, such as private gardens, agricultural islands, roadside hedges, and copses. These man-made landscapes could work as a series of habitat islands that provide stop- over points, food, and shelters for the movement of seed dispersal agents (such as crows, jays, and nutcrackers) from urban to rural areas.
         USING CITIES AS STEPPING STONES: Establishing outlier populations in cities can be regarded as a form of assisted migration (also called managed relocation or assisted colonization), which refers to the intentional translocation of species and populations outside their historic ranges to facilitate their range shifts under climate change. Here, cities are perceived as 'hot' stepping stones for poleward migration, whilst species' future distributions are viewed as moving targets, which can be achieved by successively establishing outlier populations in cities along latitudinal gradients (Fig. 2). The 'climate analogues' approach developed by CCAFS50 can help identify cities that have similar climatic conditions with those of species� native ranges at lower latitudes. Besides, the outlier populations established in cities can provide additional nursery capacity for assisted migration in local and regional spheres. For example, public parks and botanic gardens could serve as nurseries to test and accommodate translocated seeds and seedlings, providing a future supply of trees for efforts of assisted migration in nearby rural areas. Such efforts also avoid some problems associated with planting species outside their native ranges: not only because cities could provide them with extensive horticultural expertise, regular care, and record-keeping, but also because cities could offer real-world laboratories for ecologists, foresters, and managers to monitor and minimize the invasiveness of translocated species in their new environments, as well as their potential for creating pest problems, before the implementation of large-scale tree plantings..
         It should be noted urban tree plantings that aim to assist tree migration will be able to reduce losses of ecosystem services in urban environments due to climate change. Trees are a vital part of urban ecosystems. Maintaining and enhancing the long-term health of trees is essential for urban forests so that they can continue to provide ecosystem services, such as climate regulation, air purification, and carbon sequestration. The rate of recent climate change has exceeded the capacity of some native trees in urban environments to adapt, leading to increased mortality and susceptibility to fungal disease, insects, and other pathogens. One example is the native trees in the city of Bellevue, Washington, including western red cedar, western hemlock, and Douglas fir, which are experiencing a higher mortality rate due to drought stress. Efforts of assisted migration in urban areas can help establish new and better-adapted urban forests that support the sustainability of urban ecosystems.... Gardeners need to think beyond beauty when selecting species and more on the potential of horticulture to serve as a route of assisted migration.

    • June 2021 - VIDEO on assisted migration by Verge Science - 10 minutes.

    EDITOR'S NOTE - This is an extraordinarily well-written and illustrated short video on "assisted migration" as a climate adaptation tool. Two scientists provide the faces with quotes. The first, pictured left, is Angie Patterson. She's a plant ecophysiologist at Black Rock Forest in New York, and she's the one who gathers data by shooting leaves off the full-sun tops of trees. The other is Jessica Hellmann, University of Minnesota ecologist and an author of academic papers on "managed relocation" for many years. Torreya Guardians has a cameo role, too.

       EXCERPTS OF VIDEO NARRATION: "... At first, assisted migration was controversial in academia. In fact, one of the most well known efforts was carried out by a loose collective of citizen-scientists called the Torreya Guardians. They've been trying to save the critically endangered Florida Torreya. A fungus blight brought on by environmental changes has pretty much wiped them out.

    ... Human-induced climate change has irrevocably altered the planet.... We have to make pragmatic decisions about what is worth saving and why. And then we probably do have to intervene.... Indigenous perspectives are incredibly important too."

    • 9 June 2021 - "Mason man works with organization to research new habitats for endangered tree", by reporter Ashley Saari, in Monadnock Ledger-Transcript, 9 June 2021.
       EXCERPTS: Hidden away on a property in Mason, about two dozen seedlings of Torreya taxifolia are quietly growing, watched over by Daein Ballard. They may be the only specimen of their kind in New Hampshire.
         ... So far, since starting the project in 2014, he said the results have been about 50/50 whether the trees survive.
         "It can definitely survive here, but they may not thrive," Ballard said. "They're growing more slowly than they are in the south. It's probably too far north for them here."
         That's OK, he said — at the moment, his results are just a data point for where these trees might do well, and where they might not. And, Ballard said, the success or failure of Torreya taxifolia might inform how the process works with other endangered plants.
         ... Ballard said the [torreya] is a good test case for human assisted migration because it has such a small, niche environment where it grows in the wild.
         "It's a prime example of a tree in a habitat that is no longer suited for it," Ballard said. "But a lot of trees are starting to have that problem. There are a lot of trees no longer in their ideal habitat."

    ... "Trees grow slower than us and live a lot longer than us. So who's to say? Maybe the climate in New Hampshire 100 years from now will be better for them. It's a long game." Read PDF of full new story.

    • June 2021 - "Exploring the potential for plant translocations to adapt to a warming world", by Sarah E. Dalrymple, Richard Winder, and Elizabeth M. Campbell, in Journal of Ecology.
    EXCERPT of "1. Introduction": This Special Focus assembles research in Journal of Ecology and in Ecological Solutions and Evidence to examine the potential of global plant translocation activities as an adaptation strategy for climate change. We explore the various roles that plant translocations could play (Figure 1). First, we discuss the current state of knowledge on plant translocations, before synthesising evidence that supports the use of plants as reliable bioassays of climate change. Second, we explain how translocations could be repurposed into a coherent monitoring system of ecological response to climate change. Finally, we evaluate the potential for translocations to address species range loss and make recommendations for advances in policy, practice and knowledge generation to mitigate biodiversity losses due to climate change.

    FULL TEXT of "2. A Cross-Sector View of Plant Translocations": Plant translocations are the deliberate movement of plants or seeds/spores from one location to another whereby the recipient site is a natural, semi-natural or managed ecosystem. Our definition includes conservation translocations as defined by the IUCN (IUCN/SSC, 2013) and translocations undertaken when the main motive is natural resource management (sensu Pedlar et al., 2012), environmental improvement or ecosystem service provision (Winder et al., 2011). Although there have been many persuasive calls to work together more cohesively across sectors — conservation, forestry and horticulture (e.g. Pedlar et al., 2012) — to share conceptual advances and best practice for plant translocations, we are not aware of any meaningful attempts to overlook these traditional divides until now. This Special Focus was initiated by the Plant Translocation Network, a group of 120 researchers, practitioners and policymakers in 19 countries. The articles in the Special Focus encompass 760 past translocation attempts across Europe, the Mediterranean and North America, and showcase projected future distributions of 197 species to investigate the potential for translocations to avert range loss. The species examined vary from trees grown for commercial forest products over large spatial extents, to locally endemic xerophytes that are highly vulnerable to environmental change. By incorporating this breadth of research and practice, we hope to demonstrate that plant translocations are a valuable tool for understanding plant response to climate change and can form the basis for a global system to monitor biological impacts of climate change.

    EXCERPT of "3. Plant Translocations as Bioassays of Global Climate Change": - Plants are physical manifestations of a complex environment. Ecological niches of plants are a product of biotic interactions and climatic limits to survival and growth across seasonal, annual and decadal time-scales, with some plants persisting for several centuries. In a rapidly changing world, this integrating quality is a valuable characteristic enabling the use of plants as climate bioindicators where mechanistic responses to warming and drought can be defined and monitored into the future. However, simply observing plant response to climate change is beset by problems such as the difficulties in separating climate from non-climatic causes of population loss, a lack of understanding of how local genotypes tolerate change and the confounding effect of dispersal limitation which prevents species from occupying suitable climate space as conditions shift (Svenning & Sandel, 2013). Correlative methods can be used to describe climate change impacts at the scale of whole species range, but they focus on population losses without considering sub-lethal impacts on fitness, dispersal constraints or biotic interactions. They are beset with detection problems resulting from a lack of confirmed absences (Jetz et al., 2019), and poor understanding of physiological thresholds for population survival (Urban et al., 2016). Transplant, or translocation, studies have obvious advantages over observational or predictive studies by empirically testing the response of plants across a range of conditions (Table 1).

    EXCERPT of "5. Plant Translocations as Solutions to Climate-Induced Biodiversity Loss. The term translocation has typically been used in the context of reintroduction whereby a population of a threatened species is created within the indigenous range to address population loss in that region (IUCN/SSC, 2013). However, climate change is rendering portions (or the entirety) of species' indigenous ranges, unsuitable thereby constraining the use of reintroductions.... Recognising the challenges posed by climate change, conservationists are now cautiously exploring the use of plant translocations in management interventions, using terms such as 'assisted colonisation', 'assisted migration' or 'managed relocation'. Generally speaking, these all involve the intentional movement of individuals, populations or species to areas outside their indigenous range (IUCN/SSC, 2013), as a strategy for adapting conservation management to a changing climate. In this context, it is recognised that movement outside a species range entails risks where plants could become vulnerable to other factors (e.g. disease). In forestry, 'assisted migration' is viewed more favourably as a practice capable of matching planted tree populations to future climates. ... We expect that dominant tree species threatened within their range (e.g. coast redwood) would have to be translocated at a landscape level to protect overall habitat, ecosystem productivity and associated species. Implementing translocations at such a scale requires an ecosystem-level perspective.

    • June 2021 - MINI-REVIEW: "Disentangling the social complexities of assisted migration through deliberative methods", by Shannon Hagerman and Robert Kozak, in Journal of Ecology.
    EXCERPT: ... In the case of plant translocations, particularly interventions outside of native range, a reliance on over-simplified measures of ecological and economic parameters is problematic in that it fails to address the complex realities of the challenge, including myriad scientific uncertainties (from the models themselves to the effectiveness of technologies), the oftentimes unknown consequences of interventions for different social groups, and the variable and commonly contested labile value positions held by these groups. In order to construct and contextualize this problem to begin with, we argue that the analysis must begin with the following underexamined questions: Whose values does an intervention serve? Whose vision for the future is being advanced? Who will benefit? And what forms of knowledge help us know (Jasanoff, 2003)? These questions, and the analytical approaches to examine them (including insights relating to the ways that different forms of knowledge are more or less connected to structures of power and the implications of this for understanding the science-policy interface; Jasanoff, 2004; Turnhout, 2020) are well-established in the environmental social sciences, but have not yet been fully applied to the challenge of plant translocations. In this review, we argue for the need to broaden the (inter)disciplinary conversation as it pertains to understanding plant translocations, and that connecting these additional insights to decision-making requires methodological advancements in deliberative methods that are tailored to the particulars of this problem context.
         We begin by describing the example of a large-scale interdisciplinary plant translocation research project, co-led by the authors, that was designed to better understand public, stakeholder and expert perspectives on the potential for assisted migration in British Columbia's public held forests. Next, we connect insights arising from this project to key debates in deliberative public engagement, and offer a tentative pathway forward for a deliberative focussed research agenda for plant translocation research.... Given the rapidly evolving trajectory of plant translocation work from ideation to pilot projects to institutionalized programs, this is a critical moment to foster dialogue between the diverse scholarly and applied communities involved.... Our approach was grounded in a mixed-methods design, where we deployed methods that ranged in degree of and potential for interactivity and deliberation. These included a specialized public survey of attitudes, values and risk tolerance for assisted migration that contained information tutorials, deliberative 'nudge' elements, and opportunities to revisit and change previously stated preferences and explain why, participatory focus group sessions and semi-structured interviews with key stakeholders that allowed for more in-depth explorations across a range of topics... What we found was general support for assisted migration within geographic range (similar to widely used approaches like natural regeneration and local tree breeding), but much less support for assisted migration outside of geographic range (approaching more interventionist approaches like the use of non-native species and genetically modified organisms). Crucially, the deliberative elements in our survey revealed a great deal of lability in these preferences. In particular, when respondents received a 'nudge' that provided more information — especially in the form of assurances about forest resilience and ongoing research and monitoring — they were highly likely to change their minds about supporting or opposing assisted migration as a viable forest management strategy.
         ... Issues of representation and expanding the range of expertise considered in environmental decision-making is a longstanding challenge. Barriers include contested land ownership, plural value systems and uneven relations of power to name a few. We see all of these issues at play in British Columbia, where the range of groups consulted on matters related to the assisted migration/translocation of tree species has tended to follow powerful actors who are firmly embedded within the current model of forest governance, namely, industry and government representatives and select experts affiliated with each. At the most fundamental level, this narrow representation matters because those involved generally define the problem and shape the understanding of the problem itself — from outlining the issues at stake and formulating sets of viable options to demarcating the nature of threats and crafting plans for implementation. A more specific consequence of engaging only a select group of actors in consultations is the resultant narrowing of expertise. We see stark evidence of this in the context of the development of assisted migration policies (Pelai et al., 2021), where Indigenous and local knowledge have been systematically relegated to the margins. This is not an isolated finding, nor are its consequences benign. An adherence to positivist science as the sole primary credible source of knowledge input to policy has been shown to be a tool of 'social exclusion' within the field of forest management (Forsyth & Walker, 2008, p.12). While expert judgement is central to robust environmental decision-making, without additional perspectives, it can also constrain and limit important insights and other legitimate forms of knowledge that can inform the definition of the problem itself.... In the case of assisted migration in BC, Indigenous knowledge was dismissed by some precisely on the basis that it lacks 'validity', but issues of validation also extend and apply to knowledge produced within different corners of the scholarly literature (e.g. emergent, qualitative).... Yet, we do see the potential of this particular moment, with an increasing recognition of the value of diverse knowledge systems and a willingness on the part of institutional funding agencies to integrate socially based methodologies into larger-scale natural sciences research.... In the context of British Columbia, for example, First Nations can no longer be considered usufruct stakeholders of vast areas of forestlands, but as rightful owners, pursuing land management in accordance with their own vast knowledge, practices and laws. From the perspective of researchers employing deliberative methods, this requires the use of a decidedly decolonizing approach (Smith, 2012) as a means of fostering meaningful and trusting relationships, co-creating research questions and protocols, and co-producing knowledge.

    CONCLUSIONS: ... Some may interpret our suggestions here, particularly with respect to expanding knowledge and expertise, as undermining the role of science or evidence-based decision-making. Nothing could be further from our intent. The abundance of data, produced by Western science, that affirms the ways in which humans are driving potentially ruinous environmental change is crucial for understanding the complexities of our world and for developing solutions. That said, the scientific process is not as immune to social production as many would like to think that it is (Jasanoff, 2004; Oreskes, 2004; Sarewitz, 2004; Turnhout, 2020). This, again, is not to say that data and evidence — in a Western scientific sense — should not be a key input to decision-making. It should. Rather, it is that science is always the 'view' from somewhere (Jasanoff, 2017). It is situated, it is partial, and it can be steeped in colonial and racist ideologies (Smith, 2012).

    • July 2021 - "Why climate change is forcing conservationists to be more ambitious: by moving threatened species to pastures new", by Sarah Elizabeth Dalrymple, in The Conversation.
    EXCERPTS: ... Conservation translocation, also known as assisted migration, assisted colonisation and managed relocation, describes interventions that could be used to tackle climate change-driven species declines and extinctions. Instead of leaving species to suffer in hotter and drier environments, we can try to expand their range by moving them to new habitats. This overcomes situations where species can't move by themselves, such as plants whose seeds disperse only a few metres at a time, or birds who won't leave the safety of their woodland home to seek new territory. However, this approach remains controversial due to the perceived risks of moving species to ecosystems they've never experienced before. Risks include spreading diseases into new habitats, aggressive competition with resident species for prey or space, and the introduction of new predators.... A new paper on assisted migration from a team of international researchers calls for the risks of translocation to be balanced against the risks of doing nothing at all. Given the immediacy of the climate crisis, it is now the path of least risk that we must take.
         ... There are only a handful of attempted assisted migrations undertaken specifically to reduce the negative effects of a warming world. A good example is the western swamp turtle: Australia's rarest reptile, thought to be extinct for a century but recently discovered near Perth.... trial translocations are already reporting good results.
         Plants are in a similar predicament. In a recent collection of papers in the Journal of Ecology, a group of Italian researchers estimated under pessimistic (but highly probable) climate change scenarios that 90% of 188 threatened plant species may need assisted migration to cope with habitat loss. But while researchers are using computer models to predict the future needs of threatened species, one group has decided that the time to act is now. The Florida torreya, the most endangered coniferous tree in the US, has been moved north by a group of citizens known as the Torreya Guardians. They exploited a loophole in US law that allows plant translocations on private land by the public but prevents federal conservation authorities from doing the same thing. The species' current range is extremely restricted but was much more widespread before the last global ice age. The Torreya Guardians argue that the specimens of Florida torreya growing across the US provide evidence that the species can thrive beyond its current restrictions.
         With new temperature records being set all the time — and melting ice, sea-level rise and historic droughts affecting the whole planet — it's only a matter of time before climate-induced extinctions become a regular feature in the headlines. It's time for calls for better global policy on assisted migration to be heeded. We need guidance so that we, as a global community of concerned citizens and conservation scientists alike, can act decisively to protect the survival of threatened species.
    • 26 August 2021 - "Managing for RADical ecosystem change: Applying the Resist-Accept-Direct (RAD) framework", by Abigail J Lynch et al., July 2021, Frontiers in Ecology and the Environment.
    ABSTRACT: Ecosystem transformation involves the emergence of persistent ecological or social-ecological systems that diverge, dramatically and irreversibly, from prior ecosystem structure and function. Such transformations are occurring at increasing rates across the planet in response to changes in climate, land use, and other factors. Consequently, a dynamic view of ecosystem processes that accommodates rapid, irreversible change will be critical for effectively conserving fish, wildlife, and other natural resources, and maintaining ecosystem services. However, managing ecosystems toward states with novel structure and function is an inherently unpredictable and difficult task. Managers navigating ecosystem transformation can benefit from considering broader objectives, beyond a traditional focus on resisting ecosystem change, by also considering whether accepting inevitable change or directing it along some desirable pathway is more feasible (that is, practical and appropriate) under some circumstances (the RAD framework). By explicitly acknowledging transformation and implementing an iterative RAD approach, natural resource managers can be deliberate and strategic in addressing profound ecosystem change.

    EXCERPTS: ... Consequently, the cumulative costs of resistance may outpace those of directing change, despite potentially higher costs in the initial stages of the latter. Furthermore, unwavering adherence to resistance poses risks of interruption or diminution of ecosystem services, particularly if ecosystems are susceptible to threshold transformations or contrasting stable states (Millar and Stephenson 2015). In such cases, early intervention to direct changes toward a desired future state consistent with the climate trajectory may be most suitable (Hobbs et al. 2011).... A number of structured approaches and tools in the broader fields of "adaptive management" and "decision science" may facilitate defining and navigating the RAD decision space (WebTable 1). In this rapidly changing new terrain, this toolkit still needs to be tested, refined, and augmented for managers to benefit from iterative application of RAD approaches. To foster the transition to RAD, we propose a suite of guiding principles for informing decisions on how to implement RAD approaches in management of changing ecosystems.

    • 26 August 2021 - "Federal Court Signals Hope for the Climate Threatened Joshua Tree", by Jennifer Schwartz, a Staff Attorney for WildEarth Guardians, in Counterpunch.
    TAGLINE: When the very icons and namesakes that define America's national parks can no longer survive, we have a problem that should alarm everyone.

    EXCERPTS: After gearing up for the culmination of WildEarth Guardians' nearly two-year long court battle to secure federal Endangered Species Act (ESA) protections for the imperiled Joshua tree — an August 2 hearing before Judge Otis D. Wright, II of the Central District of California — my brain is teeming with factoids about these beloved plants and the perils so many Mojave Desert dwellers face.
         The combined threats of climate change, invasive grass-fueled wildfires, human expansion, and habitat degradation have already reduced the richness of the region's biodiversity by about fifty percent over the last century. Striking losses of bird communities are increasingly evident. Recent studies describe mass die-offs of other regionally endemic plants from prolonged droughts. Records from Twentynine Palms weather station show that not only have average daytime temperatures already increased 2° F over the last 40 years, but nighttime lows in the area are nearly 8° above average —; so even if precipitation levels don't decline (though they already have) the evaporation rate is much higher so less water actually reaches the desert floor to get soaked up by native plants. Graveyards of charred Joshua trees now blanket the Mojave National Preserve after 2020's Dome fire swept through and destroyed an estimated 1.3 million of these majestic desert icons. And for the past two consecutive years, summertime temps have reached a mind-numbing 130° F.
         Desert ecologists believe that many Joshua trees are now living in an environment that is no longer conducive to replacing themselves — older trees in hotter and drier portions of the Mojave are dying off and researchers aren't finding any baby trees in those areas to replace them. But even aside from the lack of new, young Joshua trees in much of the southern Mojave, every peer-reviewed study to model future climate impacts to this species agrees that most of their current range will be rendered climatically unsuitable by the end of the 21st century under the most likely greenhouse gas emissions scenarios — including nearly the complete extirpation of Joshua trees from their own namesake, Joshua Tree National Park.
         ... In other words, all the available scientific evidence points in one direction: Joshua trees will be in danger of extinction throughout most of their current range by century's end. This dismal projection need only be "likely" for Joshua trees to meet the ESA's definition of a "threatened" species and be entitled to the Act's broad federal protections. Indeed, this whole concept of protecting threatened species (as opposed to only those that are already "endangered" with the risk of imminent extinction) reflects what our federal courts have dubbed the ESA's policy of "institutionalized caution" — to conserve species before they're conclusively headed for extinction.
         Sadly, the U.S. Fish & Wildlife Service chose to deliberately ignore a wealth of science showing the Mojave will undergo truly profound transformations in the coming decades. Instead, the agency summarily concluded that Joshua trees are long-lived, hardy desert plants distributed over broad geographic areas so that must mean they'll be able to weather climate change and various other combined stressors.
         Given just how blatant the agency's conscious disregard of the available science was, I shouldn't have been surprised when Judge Wright suggested at the outset of our hearing two weeks ago that Guardians' position was more reasonable than the government's. In fact, Judge Wright indicated that the clarity of Guardians' legal arguments and the record science obviated the need for any additional oral argument from me (lead counsel). He asked only one question to defendants: would USFWS consider redoing its decision not to list the Joshua tree? Alas, the government's attorney responded with a strident "NO." So while we're disappointed with the Biden administration's refusal to voluntarily walk away from this terrible Trump-era listing decision, we're left at least feeling optimistic that the Court will now wade past all USFWS's pleas for deference, its unsupported assertions and selective cherry-picking of the record evidence, and force the government's hand at a better decision.
       We know Joshua trees are long-lived plants that have evolved to withstand harsh desert conditions, but living on the edge of what is already one of the most extreme environments is precisely why this species is so vulnerable to further rising temperatures, prolonged droughts, and uncharacteristically severe fires. We also know that the ESA isn't the legal mechanism to solve climate change. But it can give climate threatened species like the Joshua tree a fighting chance.
         If listed, USFWS would be required under the Act to develop a "recovery plan" and formally designate "critical habitat" for the Joshua tree. In this case, that would likely necessitate protecting higher elevation areas that climate modeling experts predict will have the right temperatures and precipitation levels in the future for Joshua trees to successfully reproduce and survive. But these areas (see all that land depicted in green on the map above) are far too distant for these stationary plants and their sole obligate pollinator (a Yucca moth that can only fly a few hundred feet at best) to migrate to on their own, before their current habitat is lost. So, in all likelihood, Joshua trees will need a recovery plan that involves human assisted migration to persist beyond the 21st century. It'll also likely necessitate increased efforts to combat invasive grasses that are fueling so many devastating fires in this region.

         Those are the efforts USFWS should be devoting its limited resources to — not litigating its deeply flawed listing decision. Here's to hoping a favorable court decision will now drive the Joshua tree's preservation. In the meantime, please take action and urge the Biden administration to protect Joshua trees.

    • 22 September 2021 - "Cuyahoga Valley National Park Struggles With The Effects Of Climate Change" - by Amy Eddings, Ideastream Public Media.
    EXCERPTS: ... ... The department (DOI) released new guidance in April, built around a decision-making framework known as "Resist, Accept, Direct." "So, black locust here, historically, we've considered it invasive. It comes in and it will take over a whole field," said Davis. "But it is naturally present just south of here, like in southern Ohio and Kentucky. So, in the past we've been fighting that tree in some sites. And now we're trying to, like, not so much, because it's probably on its way." Assisted migration comes under the category of "directing" change in the "resist, accept, direct" guidance. Here, park managers shepherd a landscape toward a new ecosystem that is presumably more stable, more adaptable and more desirable than it would be if left alone.
    • Nov-Dec 2021 - "Can We Move Our Forests in Time to Save Them?" - by Lauren Markham, Mother Jones. (Same article also in Wired.)
    EXCERPTS... Back in 1992, forest geneticists F. Thomas Ledig and J.H. Kitzmiller coined the term "assisted species migration" in a seminal study in the journal Forest Ecology and Management. Since then, hundreds of biologists and geneticists like Brad St. Clair have been studying how best to move forests in advance of their looming destruction. To do so requires a complex set of mapping and experiments�understanding, for instance, what climate trees are best suited to grow in, what region will most closely resemble that same climate in, say, 50 years, and what adaptations best ensure that a tree will take root and flourish, build symbiosis with the soil fungi, and not end up a mere matchstick awaiting the next megafire. St. Clair is something of an assisted migration evangelist, a firm believer that we need to move tree populations, and fast, if we want to keep apace. But due to bureaucratic logjams and a fervent commitment to planting native species, there's very little assisted migration in the United States — unlike in Canada, where the practice has been adopted with more urgency in recent years. St. Clair and other Forest Service scientists are working to transform assisted migration from a mere research subject to a standard management strategy in our vast, imperiled public lands.... During the talks he gives about his research, he likes to show an image from Lewis Carroll's Through the Looking-Glass, in which the Red Queen charges forward with her crown and sturdy scepter, pulling frenzied Alice along in her wake. He had the slide printed out and handed it to me as we walked. "Now, here, you see," the Red Queen says to Alice, "it takes all the running you can do, to keep in the same place." "So that's what we gotta do," he told me, pointing to the Red Queen. "We gotta run."
         While assisted migration is a relatively new concept, the movement of forests is as old as trees themselves. Since they first evolved, trees have been shifting north and south, east and west, up and down in elevation as the climate has changed. Forests outran the frost as an ice age set in, and as the ice began melting, they darted back the other way, traversing mountain ranges and unfurling themselves across continents�moving, sentiently, toward climatic conditions that suited their ability to grow and produce the trees of the future.
         ... Proponents of assisted migration claim that this balance has already been upended by climate change. They also stress that assisted migration is an umbrella term for a range of activities, some way more far-reaching than others. The most drastic intervention is known as assisted species migration, which transplants species of trees from places where they naturally occur to faraway places where they do not. Then there's assisted range expansion, which plants trees slightly outside their naturally occurring territory. The strategy involving the least human intervention is known as assisted population migration, which, like St. Clair's studies of Douglas fir, plants trees of a single species with certain adaptations to a new location where other members of that same species already live. Most scientists advocate the latter two strategies and consider the first one too extreme.
         So how to safely move a population to a new habitat — and to know how far to do it, and how fast? "If I knew the answer to that," Forest Service scientist Kas Dumroese told me, "I'd have the Nobel Prize." To find out which plants are best suited to which environments, scientists tend to use something called the Common Garden Study, which, like the artificial forest I visited in Oregon, plants flora from a wide range of locations — and thus adapted to a range of conditions — on a single plot to study their response and growth patterns. What scientists have found in most assisted migration garden studies is that the trees that do best are those whose parents and ancestors thrived in similar terrain. If you move a population of trees adapted to a particular climate too slowly, it's bound to succumb to the hotter, drier conditions brought on by climate change. But move it too fast to a colder, wetter climate, and the trees might fall victim to too much frost, or to root rot in damp conditions that make them vulnerable to pests.
         Shifting trees that can handle midcentury climate projections — so new forests are adapted to the temperatures of roughly 2040 to 2070 — seems to be the Goldilocks balance that will ensure a population's survival. But there are other important considerations, including the symbiotic relationship between soil fungi and trees. Suzanne Simard, the author of the recent bestselling book Finding the Mother Tree, explains that, while trees will likely find some symbiotic mycelium as long as they are moved within their species' existing range, that mycelium might not be the best adapted for their needs. Trees can't be seen as growing in isolation, but need to be considered in terms of the overall health and relationships of a larger ecosystem. "There's a lot we don�t know," she told me. Assisted migration "is risky, but, you know, we also have no choice. We have to start experimenting with this. We have to start moving things around and watching and seeing how they do." The Forest Service scientists who study assisted migration couldn't agree more, and they hope that the agency's forest managers will start using this strategy in actual forests. Despite decades of research, the Forest Service has rarely put assisted migration into practice, in part due to some foresters' and scientists' resistance to moving trees outside their agreed-upon range. In the 1930s, the Forest Service created the idea of seed zones — mapping the landscape into areas "within which plant materials can be transferred with little risk of being poorly adapted to their new location," as the agency states on its website. Ever since, forest managers have stayed loyal to these zones when selecting seeds for planting.
         While assisted migration isn't strictly prohibited by the Forest Service Manual and its accompanying handbooks — the official policy documents that, as Forest Service land manager Andy Bower explains, guide "every aspect" of how the agency operates — it isn't encouraged, either. Last fall, Bower, St. Clair, and five other forest geneticists in the Forest Service proposed changes to the manual that include assisted population migration and, in some cases, slight range expansion, as forestry strategies. If their recommendations are accepted, it could drastically accelerate the use of assisted migration nationwide.
         The Forest Service doesn't have to look far for an example of a country taking a more aggressive tack: Canada is substantially ahead of the United States in research and implementation of assisted migration. This is, in part, a result of urgency. In the early aughts, aided by worsening climate change, lodgepole pine forests were devastated by invasive bark beetles and massive wildfires. This was also true in the United States, but when it happened in Canada, the country acted far more aggressively. "It was huge," Greg O'Neill, a scientist working for the Canadian Forest Service, told me, "like they got hit by a sledgehammer. It really woke up the forestry community." The Forest Service of British Columbia launched the Assisted Migration Adaptation Trial, or AMAT, in 2009, planting roughly 153,000 trees to see how each would fare in different climates. With more than a decade of results, they have begun to use this data to reforest areas that have been logged or burned.
         ... But even in the most optimistic of climate scenarios, the forests need to get moving, from south to north, from lowlands to highlands, so that our landscapes remain populated with trees. "It's almost like we have this temporal-centric view of nature," O'Neill said. "A lot of people view climate change as something that's going to happen, not something that has already happened." And though all trees can generally survive a change of 4 degrees Fahrenheit in either direction, O'Neill reminds me that 2.7 degrees — the amount that the climate has already warmed in the past century — is a cataclysmic change of circumstances from a tree's perspective. Seen this way, he said, "these trees are already a long way from home." If all we do is help them get back to the kinds of habitats they'd lived in before the climate began to change so rapidly, he added, "I think we'll be doing a great service."
         ... If a forest [after a devastating fire] will be replanted anyway, why plant what was already there and burned, when we can reforest these burn sites — which have grown all the more common, and so much bigger — with trees that will be better suited to that future in 30 to 50 years? A stressed forest brings diseases and pests, which kill trees, offering more kindling to burn. The healthier a forest, the less likely it is to catch fire.
         ... Joshua Tree National Park is central on my personal map of sacred places. It was the first place I went backpacking as a kid, the first place I slept under the stars, and a place I've returned to again and again to reattune with the world. The Joshua tree's silhouette is imprinted on many significant memories throughout my life — these are trees I really, really, really want to survive. After getting vaccinated last spring, I headed down for a few days in search of desert light and those fabled trees. I drove from the south end of Joshua Tree to the north, moving through a low, flat valley where Joshua trees and cholla clustered in mighty, baffling stands. The Joshua trees here in the valley looked healthy enough, but botanists know better: Look closely, they told me, and you'll see there are no young sprouting among the noble elders. This was a forest of childless parents, living their final days as the last of their kind to call that spot their home....
    • November 2021 - "Assisted migration poleward rather than upward in elevation minimizes frost risks in plantations" - by Zihaohan Sang, Andreas Hamann, and Sally N. Aitken, Climate Risk Management.
    ABSTRACT: When assisted migration is used to address climate change, tree seedlings may have to be moved to substantially colder environments in anticipation of climate warming over their life span. Here, we evaluate frost risks for four economically important forest tree species of western Canada, Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), interior spruce (Picea glauca, P. engelmannii, and their hybrids), and western larch (Larix occidentalis), when moved to adjacent northern and higher elevation seed zones that are cooler by approximately 2 degrees C.... Based on daily interpolated climate data between 1980 and 2019, we find that late spring and early fall frost risks do not change significantly for transfers toward the north (<1 percentage point in most cases). In contrast, moving planting stock toward higher elevation generally leads to a substantial increase in exposure to unseasonal frosts (late spring frosts: 0.5% to 9.4%, early fall frosts: 0.8% to 17.1%). We conclude that transfers toward the north are preferable to transfers up in elevation in reforestation of these tree species in western Canada.
    • November 2021 - "Regulatory Fragmentation: An Unexamined Barrier to Species Conservation Under Climate Change", by Alejandro E. Camacho and Jason S. McLachlan, Frontiers in Climate.
    ABSTRACT: Requirements for the protection or restriction of species are based on regulatory classifications such as "native" or "invasive," which become anachronistic when climate change drives species outside of their historical geographic range. Furthermore, such regulatory classifications are inconsistent across the patchwork of land ownership that species must traverse as they move between jurisdictions or when transported by humans, which obstructs effective regional management. We surveyed the U.S. laws and regulations relevant to species movement and found that the immigration of species to new jurisdictions makes paradoxical existing regulatory language that sets the categories of species deserving protection or removal. Climate change is universal and progressing rapidly, which provides a shrinking window to reconcile regulatory language originally developed for a static environment.

    EXCERPTS (re assisted migration): Species migrations of hundreds to thousands of kilometers were a common response to past periods of rapid climate change (Davis and Shaw, 2001), and, because movement was not coherent across species, the species composition of ecological communities changed substantially with these climate disruptions (Blois et al., 2013). Contemporary climate change is already driving species shifts and community realignment (Blois et al., 2013; Moritz and Aguda, 2013). Since the rates and magnitude of contemporary climate change are projected to be as high or higher than those past analogs (Raftery et al., 2017), it is virtually certain that species range shifts will grow larger and more ubiquitous this century. Species displaced long distances by climate change will thus increasingly have to traverse a patchwork of jurisdictional boundaries to survive. However, the regulatory status of species that disperse beyond their historical ranges varies from jurisdiction to jurisdiction and often hinges on whether they are considered "native," an ambiguous designation for species undergoing range shifts. Like habitat fragmentation, which can impede the capacity of migrating species to keep up with shifting climates (Warren et al., 2001), such "regulatory fragmentation" can compromise management strategies under climate change (Craig, 2008).
         ... Because active adaptation strategies, such as managed relocation, are already being discussed and used as a component of species conservation under climate change (Richardson et al., 2009), it is also important to consider the impact of direct human assistance on the regulatory status of spreading species. In most jurisdictions, if the governing authority determines that species moved by humans to minimize or mitigate the impact of climate change are "introduced," such species receive less regulatory protection and more regulatory resistance than if their arrival was not facilitated by direct human intervention. The National Parks Service, for example, defines and manages "exotic species" as "those species that occupy or could occupy park lands directly or indirectly as the result of deliberate or accidental human activities," while native species include "all species that have occurred, now occur, or may occur as a result of natural processes on lands designated as units of the national park system," (U.S. National Park Service, 2006). Thus, active management intended to preserve a species might paradoxically lead to lowered protective status for that species. Laws favoring purportedly "natural" migration over conservation-oriented human introduction are increasingly untenable in the context of a rapidly changing patchwork landscape that subjects wildlife to substantial physical and regulatory dispersal barriers.
         ... Here, we use illustrative scenarios to show how current regulatory language can become problematic, even paradoxical, when climate drives species out of their historical ranges. Our goal is to make regulatory fragmentation as visible to conservation biologists and strategists as habitat fragmentation, which is routinely used in the assessment and planning of species conservation (Dickson et al., 2017). Our approach is to use simple "climate envelope" projections of species range shifts, developed by us and others, not as predictions but as plausible scenarios, illustrating how far, and by which route, species might move under climate change this century. We then collate and interpret the set of laws and regulations that apply to species movement in the jurisdictions that the species crossed in our "migration" scenarios. This approach allows us to identify a set of likely unforeseen consequences of the current regulatory landscape. We believe that the types of regulatory paradoxes illustrated by our scenarios are likely to pose general problems in the near future, but we emphasize, for clarity, that the specific migratory pathways we delineate in this paper are only realistic scenarios.
         ... Because active adaptation strategies, such as managed relocation, are already being discussed and used as a component of species conservation under climate change (Richardson et al., 2009), it is also important to consider the impact of direct human assistance on the regulatory status of spreading species. In most jurisdictions, if the governing authority determines that species moved by humans to minimize or mitigate the impact of climate change are "introduced," such species receive less regulatory protection and more regulatory resistance than if their arrival was not facilitated by direct human intervention.
         ... The existing paradigm for invasive species management focuses on prohibiting only certain blacklisted species. In the novel ecological communities created when "new natives" mix with "old natives," the difficulty of establishing such lists will be compounded by ambiguity about the status of "new natives" combined with the difficulty of assessing the acceptable impact of "new natives" in the context of novel ecological communities. These problematic aspects of determining "invasive" status in a dynamic biological setting thus raise the risk both of inhibiting the movement of species deemed beneficial and of facilitating the movement of species that may cause considerable harm.
      Black locust (Robinia pseudoacacia), a native tree in the Ozarks and southern Appalachians, is identified as an ecological threat in the Upper Midwest, due primarily to its habit of establishing dense groves that exclude native vegetation (Hoffman and Kearns, 1997). Eight states in the eastern US consequently have laws or regulations limiting the movement of black locust, or encouraging its eradication. In Wisconsin, black locust is listed as a "restricted" invasive species, mandating a statewide plan for controlling the species, including prohibitions on the transport, possession, transfer, or introduction of the species.
         Ironically, in projections of the habitat range of black locust under a high greenhouse gas emissions scenario, black locust is projected to become rare or extinct in the western range of its native habitat by 2,100, shifting its primary habitat to Northeastern and Midwestern states, including states where it is currently considered invasive (Figure 2; Peters et al., 2020).
         Might a policy of continued black locust eradication in Wisconsin look as non-sensual to future generations as it would for us to consider black spruce to be "invasive" in formerly glaciated Canada, and "native" in the Southeastern US, where it thrived in glacial times?

    ... The current regulatory paradigm emphasizes the preservation of historical conditions and the minimization of human intervention, but these goals are becoming increasingly at odds with each other. Moreover, these standards will be increasingly untenable as species make essentially permanent range shifts accompanying climate change. Accordingly, it is important to immediately begin the difficult task of establishing new standards. Rather than a myopic focus on promoting native species and minimizing active management, laws and policies should be reoriented to promote beneficial and discourage harmful movement. This necessarily means increased emphasis on ecological health over historical and wildness preservation objectives in conventional conservation strategies like ecosystem-based and landscape-level conservation planning, species recovery planning, or even private land management incentives to increase or decrease permeability (Kostyack et al., 2011). Yet advancing ecological health in the face of landscape-level climatic change will likely require employment of active interventions such as assisted migration, biotechnological strategies (Camacho, 2020), and reconsideration of invasive management strategies.
         ... We unequivocally acknowledge, however, that determinations of what are beneficial or harmful movements are value laden and contextual. Science and management expertise alone cannot solve the problem. To be sure, policymakers will need to work closely with scientists and local managers to develop and implement measurable criteria that balance the increasingly competing goals of preservation and biodiversity in the broader framework of promoting ecological function at broad scales.... Conservation scientists and managers must increasingly direct their efforts toward characterizing the value of ecological phenomena and the metrics of operationalizing values of ecological constituents, processes, and systems in the context of the tradeoffs raised by resisting, allowing, or assisting species movement (Camacho, 2020)
         If legislators determine that humans should take an active hand in protecting species from the ravages of climate change by introducing them to new habitats, it will no longer make sense to deem such "introduced" species less worthy of protection in their new homes. Such decisions are fundamental value choices that raise tradeoffs that not only require the input of the resource management and scientific communities. More importantly, they necessitate thoughtful and inclusive public deliberation through the democratic process. Accordingly, ensuring robust conservation governance processes is at least as important an endeavor for conservation law in the Anthropocene. Federal and state legislatures in the U.S. must reevaluate not only the ends but also the means of species management policy under climate change. New dynamic and adaptive processes and institutional authority are needed for managing species as they move across jurisdictional boundaries (Camacho, 2020). This includes integration of adaptive species movement management in, for example, ESA recovery planning and habitat conservation planning for listed species, federal land management planning, and state wildlife action plans for other vulnerable species.... More fundamentally, a meaningful democratic dialogue about the goals, procedures, and structures of species management in a changing world is needed to foster regulatory species management policies that are as complex and dynamic as the threats to ecological function and diversity presented by a rapidly changing climate.

    SUGGESTED READING: Three previous (and lengthy) law review articles by A. Camacho also deal with assisted migration policy, ethics, and regulation: 2010 - "Assisted Migration: Redefining Nature and Natural Resource Law Under Climate Change"; 2015 - "Going the Way of the Dodo: De-Extinction, Dualisms, and Reframing Conservation"; 2020 - "De- and Re-Constructing Public Governance for Biodiversity Conservation Symposium: Governing Wicked Problems"

    • 2 December 2021 - "Michigan's forest stewardship heritage", by Kathleen Lavey, Michigan Department of Natural Resources.
    EXCERPTS: "This new era with climate change is going to require a tremendous amount of stewardship," Jason Hartman said. "Everyone seems to want to plant more trees, which is great. We just need to be strategic." Some important Michigan trees such as aspen and jack pine are at the southern end of their current geographic range and need cool temperatures to thrive. But DNR data shows that mean temperatures in the state rose between 1969 and 2020. That means Michigan's forests may lose a few iconic tree species in the next 100 years, but at the same time may gain a few different tree species as southern trees expand their range to the north.
         One of the stewardship tasks the DNR is considering now is a process known as assisted tree migration. "We are basically just selecting some species from farther south to plant as tests across different latitudes in Michigan," Hartman said. "For instance, we are planning to plant some hickory trees in Lansing and Gaylord and Shingleton. We want to see which species perform best if assisted migration were to become operational."
         Hickory currently thrives in southern Michigan but becomes rare as you head north. It's an important prospect because its hard-shelled nuts provide food for wildlife through the winter. Other hardwood species under consideration for assisted migration include yellow poplar, walnut and perhaps some of the southern species of oak or blue ash, which resists the invasive and destructive emerald ash borer.
         DNR foresters also are looking at species that could possibly replace red pine and jack pine in the distant future, and additional experiments are likely to include growing short-leaf pine and pitch pine in Michigan. Short-leaf pine grows in southeastern Ohio, the Ozarks and much of the south. Pitch pine currently grows on the east coast and in portions of the south... "We're not going to move any species that have the potential to be invasive," Hartman said.
    • 15 December 2021 - "Risks and opportunities of assisted colonization: The perspectives of experts" - by Irma Kracke et al., Nature Conservation.
    EXCERPTS: ... We evaluated the specific opinions of global experts for assisted colonization on potential risks and opportunities that this approach offers. For this purpose, we used an online survey targeted at authors of scientific publications on assisted colonization. The majority (82%) of the 48 respondents were in favor of applying assisted colonization for species that are at risk of global extinction due to anthropogenic environmental change. Most respondents agreed that assisted colonization should be considered only when other conservation tools are not available and that certain preconditions must be met. Some of these were already highlighted in the IUCN guidelines for assisted colonization and include a completed risk assessment, clearly defined management plans and secured political as well as financial support.... Regarding possible risks, most of the respondents were concerned about consequences like failure of the long-term establishment of the translocated species and the transmission of diseases and invasiveness potentially endangering native biota.... In the original survey the term "assisted migration" was used instead of "assisted colonization". However, throughout this manuscript, we finally applied the term assisted colonization to achieve consistency with the terminology in the IUCN guidelines... This survey showed that ethical aspects about assisted colonization are considered of modest importance, most likely because protecting threatened species from extinction is considered to be of paramount importance.... In recent years, an increasing number of assisted colonization events have been implemented worldwide. Examples are the relocation of swamp tortoise (Pseudemydura umbrina) in Australia (Seddon et al. 2015), the introduction of the conifer Torreya taxifolia in regions north of its current range the USA (McLachlan et al. 2007), and the introduction of two butterfly species (Melanargia galathea, Thymelicus sylvestris) north of their current range in the United Kingdom (Willis et al. 2009). All these species are assumed to become threatened by climate change in their current range, and thus assisted colonization was deemed to be a useful conservation strategy.
    • MONTH 2021 - "Northwest Reforestation, Planting to Suit Current and Future Climates" Northwest Climate Hub, of the U.S. Department of Agriculture.
    EXCERPTS: After a few years of drought, including extreme droughts in 2021 and 2015, forests are showing signs of drought stress (scorched leaves and needles, flagging), and some trees have died. Many foresters and small woodlot owners are considering what they should plant that will survive current and future climate conditions. Future climate projections show increases in temperature that may occur faster than plant populations can adapt or move (migrate or disperse).... Assisted migration is receiving increasing attention as a reforestation option. Assisted migration is the human-assisted movement of plants or animals to a new habitat. Assisted migration can be used to reduce negative impacts of climate change because it involves planting trees that are adapted to current and future climates. What many people do not realize is that assisted migration is a general phrase used to refer to three different types of assisted migration:
      Assisted population migration moves seed sources from populations (usually represented by seed zones or breeding zones) to a new location that represents a different seed zone within the species range. Note in the graphic below, movement is occurring among distinct seed zones (grey areas).

    Assisted range expansion moves seed sources from populations (usually represented by seed zones or breeding zones) within the species range to suitable locations that are just beyond the current species range, mimicking a tree's ability to disperse to this new habitat.

    Assisted species migration moves seed sources from populations (usually represented by seed zones or breeding zones) to locations outside of the species range and farther away than could occur through natural plant dispersal. In this case, help by humans overcomes any natural migration boundary (noted by the dotted line in graphic below). [Assisted species migration is also called species rescue, managed relocation, or assisted long-distance migration].

    ABOVE: This simple graphic demonstrates each type of assisted migration using a conifer icon, though the three types of assisted migration are applicable to all plants (deciduous trees, shrubs, etc.). In the graphic, different seed zones are represented by distinct grey areas, and orange arrows represent the movement of plant material from one seed zone (or population) to a new location. In the graphic, the historical climate notes the movement of plant material from warmer climates to historically cooler climates.

  • "Strategic Application of Topoclimatic Niche Models in Managing Forest Change" - by James J. Worrall and Gerald E. Rehfeldt, 15 December 2021, Forests.
    ABSTRACT: Forest management traditionally has been based on the expectation of a steady climate. In the face of a changing climate, management requires projections of changes in the distribution of the climatic niche of the major species and strategies for applying the projections. We prepared climatic habitat models incorporating heatload as a topographic predictor for the 14 upland tree species of southwestern Colorado, USA, an area that has already seen substantial climate impacts. Models were trained with over 800,000 points of known presence and absence. Using 11 climate scenarios for the decade around 2060, we classified and mapped change for each species. Projected impacts are extensive. Except for the low-elevation woodland species, persistent habitat is rare. Most habitat is lost or threatened and is poorly compensated by emergent habitat. Three species may be locally extirpated. Nevertheless, strategies are described that can use the projections to apply management where it is likely to be most effective, to facilitate or assist migration, to favor species likely to be suited in the future, and to identify potential climate refugia.

    14 SPECIES: Abies concolor, Abies lasiocarpa, Juniperus osteosperma, Juniperus scopulorum, Picea engelmannii, Picea pungens, Pinus aristata, Pinus contorta, Pinus edulis, Pinus flexilis, Pinus ponderosa, Populus tremuloides, Pseudotsuga menziesii, Quercus gambelii

    EDITOR'S NOTE: Because this is the first technical forestry paper to apply a "topoclimatic niche model" (and and a very detailed scale), it is excerpted at length in the Forestry section of this webpage.

  • "Limited Range-Filling Among Endemic Forest Herbs of Eastern North America and Its Implications for Conservation With Climate Change" - by Stephanie K. Erlandson, Jesse Bellemare, and David A. Moeller, 8 December 2021, Frontiers in Ecology and Evolution.
    EXCERPTS: Species with low dispersal and poor range-filling capacity may be especially threatened by modern climate change because they are unlikely to migrate quickly enough to keep pace with changing climate (Thomas, 2011). In some cases, their realized and potential distributions might shift apart entirely, exposing them to high risk of extinction (Sax et al., 2013). In this context, many endemics might be particularly susceptible, as their distributions often reflect past marginalization by climate change (e.g., Pleistocene glaciations), and their current distributions are often restricted to unusual habitats (high elevations, north slopes) in southern areas that are surrounded by warmer, unsuitable habitat (Ohlemuller et al., 2008). Conservation of such endemics may require assisted migration (McLachlan et al., 2007). However, in the case of endemic forest herbs of the Southern Appalachian Mountains, it has been unclear whether suitable habitat already exists outside their native ranges. Our models based on current climates predicted suitable habitat north of the range margins of three endemics, suggesting that assisted migration could be successful currently and that single, larger-scale translocations might be feasible, rather than "many small steps" moving incrementally northward over decades... Notably, Diphylleia cymosa and Shortia galacifolia are known to survive, reproduce, and recruit new adults in parts of New England where they have been transplanted decades ago, making these patterns plausible (J. Bellemare, pers. obs.).
         ... In the case of the endemics investigated here, our Last Glacial Maxium projections suggest that they could have persisted near their present-day distributions in the Southern Appalachian Mountains (SAM) even during the colder climatic conditions of the Pleistocene. This pattern is consistent with horticultural observations that narrow endemics of the SAM often survive and reproduce in gardens far to the north. However, this Pleistocene context might not suggest a similar likelihood for pre-existing tolerance to the significantly warmer conditions projected for the future given that they would be unprecedented in the recent geological past. In the absence of rapid evolution or preexisting tolerances, poleward migration might be necessary for the long-term survival of the endemic species investigated here. However, natural dispersal to northern areas for endemic species may be particularly unlikely, given their apparent lack of substantial northward migration during the Holocene.... Given the severity of reductions in suitable habitat within the range and the disjunct nature of suitable habitat outside the range, assisted migration may be an important strategy for long-term conservation (Hoegh-Guldberg et al., 2008)... Our results suggest a history of dispersal limitation following the last glacial maximum along with an environmental barrier to northward migration. Conservation of endemic species would likely require intervention and assisted migration to suitable habitat in northern New England and Canada.


  • "Intentional Forests: Growing Hope for the Future" - by Marie E. Antoine and Stephen C. Sillett, 2022, International Dendrology Society Yearbook 2021.
    EXCERPTS: "... The lifespan of a tree may be long enough for human civilizations to rise and fall... Integration of conservation and restoration efforts into social and economic systems could allow a transition towards post-industrial societies, where more people might make a viable living in services related to ecosystem health.... Even if we are powerless to predict and prevent change, we can provide sufficient space for nonhuman species to adapt and persist. It is also worth contemplating assisted migration for the sake of species' survival. ... While there are improvements to be made in land management for future protection of surviving giant sequoia, climate change could render ineffectual even the best management efforts. With hotter droughts and increased frequency of severe fires, much of the Sierra Nevada could become inhospitable to giant sequoia, the most fire-resistant tree in the world.
         Does climate change mean geographically restricted species like giant sequoia are unavoidably doomed? No! Let us be proactive and hedge our bets with extensive offsite planting of this charismatic tree. We know giant sequoia thrives when planted beyond its range in temperate regions around the world. There is also the long view: redwoods once flourished across large swaths of the Northern Hemisphere until their range was constricted by glaciation. In that sense, a wider planting of giant sequoia and other redwoods is not outside the realm of natural.
         The habitat value and carbon-sequestering power of giant sequoia is undiminished in a planted tree. The question of where species 'belong' may ultimately become less important than what they can do when intentionally used across the landscape. Extraordinary problems require creative and unconventional solutions.
         Perhaps all this talk of using trees and managing the Earth strikes you as cynical. We argue that the opposite is true. A fundamental awareness that we are inseparable from nature means we have a responsibility to reexamine our vast potential for shaping life on Earth. Climate change adds a layer of chaos and urgency to our collective situation. As these unprecedented changes are anthropogenic in their causes, so too must be the solutions. Acknowledging this reality is not pessimistic or defeatist but rather optimistic and empowering. We need not be passive observers to the collapse of our biosphere!
  • "Here's how science is trying to conserve the monarch butterfly's forests" - by Thelma Gomez Duran, 17 January 2022, Mongabay News. EDITOR'S NOTE: 2022 update on assisted migration experiments of Oyamel Fir near Mexico City — planting substantially upslope, which requires positioning the seedlings under nurse plants to avoid the full intensity of high-altitude UV light damage. See also a 2021 4-minute VIDEO (with English captions) that shows the planting process.

  • "RAD Adaptive Management for Transforming Ecosystems", by Abigail J Lynch et al., January 2022, BioScience ABSTRACT: Intensifying global change is propelling many ecosystems toward irreversible transformations. Natural resource managers face the complex task of conserving these important resources under unprecedented conditions and expanding uncertainty. As once familiar ecological conditions disappear, traditional management approaches that assume the future will reflect the past are becoming increasingly untenable. In the present article, we place adaptive management within the resist-accept-direct (RAD) framework to assist informed risk taking for transforming ecosystems. This approach empowers managers to use familiar techniques associated with adaptive management in the unfamiliar territory of ecosystem transformation. By providing a common lexicon, it gives decision makers agency to revisit objectives, consider new system trajectories, and discuss RAD strategies in relation to current system state and direction of change. Operationalizing RAD adaptive management requires periodic review and update of management actions and objectives; monitoring, experimentation, and pilot studies; and bet hedging to better identify and tolerate associated risks. [NO MENTION OF ASSISTED MIGRATION.]

  • "Bibliometric Analysis of the Structure and Evolution of Research on Assisted Migration", by Lahcen Benomar et al., March 2022, Current Forestry Reports, Vol 8, pp 199-213.
    EXCERPTS: ... Since the first publications on assisted migration as a climate change adaptation strategy in 2007, the number of publications per year increased rapidly from 4 to 75 between 2007 to 2015 thereafter fluctuated moderately.... Based on the number of published articles, our results showed that the most productive author in the field of assisted migration is Cuauhtemoc Saenz-Romero from Instituto de Investigaciones Sobre los Recursos Naturales (Mexico), followed by Andreas Hamann from the University of Alberta, Canada (Fig. 3). The 15 most productive authors were from the forest ecology and management domain with research emphasizing commercial forest tree species (Fig. 3). The two most cited authors were Gerald Rehfeldt from US Forest Service (USA) and Jason McLachlan from the University of Notre Dame (USA) based on local citations.

    ... This study showed that much of the research on assisted migration has been carried out in North America, where Canada and the USA have established strong collaborative networks. Canada-USA collaborations have emphasized research related to assisted migration of populations for forest trees, compared to other research categories.... Overall, this bibliometric analysis points towards the need to establish new, long-term experiments that expand international collaborations and foster development of interdisciplinary toolkits to fill existing and evolving knowledge gaps that are important to assisted migration and its application to conservation and restoration.

  • "New Forest for a New Climate", by Greg Breining, March-April 2022, Minnesota Conservation Volunteer.
    EXCERPTS: ... By day's end, the workers treat nearly 20 acres in Split Rock Lighthouse State Park, one of four North Shore state parks where the DNR is working with The Nature Conservancy on a project to replant hundreds of acres of forest. Something makes this project different from what might have been done 20 years ago. Rather than draw from local seed sources to replant the forest of the recent past, resource managers are using a diverse mix of seedlings, some drawn from more than 100 miles to the south. The goal is a subtly different, more resilient forest that will thrive in a warmer climate.
         "We're keeping a component of the trees everyone wants on the North Shore — the cedar, the spruce, the white pine," says Liza McCarthy, DNR district resource specialist who works for state parks. "But we are adding in species that we wouldn't normally plant in large numbers in the past." These "climate winners" include red oak and yellow birch. "They're expected to do well, they belong here, but it's new to plant them in large numbers," she says.
         The state parks reforestation is one among many forestry projects around the country to adapt forests to a changing climate. The approach upends the old paradigm of preserving the forest as it existed before European settlers. In some cases, foresters, ecologists, and other land managers are actively moving in new species from as far as hundreds of miles away to prepare forests for a warmer climate. The change is an adjustment for resource managers — such as those at state parks — who have sought to preserve a sample of the past, and a challenge for those who have to figure out what might thrive in the future. "We are kind of paving a new path," McCarthy says. "So it's a little challenging because we are trying new things. It's supported by data and science but it is still different than what we've done in the past."
         ... In all, 100,000 seedlings have been planted in the past year at Split Rock Lighthouse, Gooseberry Falls, Temperance River, and Cascade River state parks. The seedlings are a mix of white pine, red oak, bur oak, yellow birch, white cedar, white spruce, and tamarack. The oaks are clear climate winners. White pine and yellow birch are local species that are expected to do well in a changing climate. White spruce and tamarack were planted because they don't require protection from deer. Iconic boreal trees such as spruce, cedar, and birch were planted on north-facing slopes and similar shady "microclimates" with cooler soil temperatures. "We are still planting trees that aren't projected to do well with climate change, but we're considering where they are planted," says McCarthy. "People love them and they're great animal habitat and part of our plant communities here."
         ... These North Shore sites aren't the only parks forced to adapt their forests to a changing climate. Nerstrand Big Woods State Park in southeastern Minnesota has lost many of its namesake towering sugar maple, basswood, oak, hickory, and other hardwoods. A wetter climate and heavier rains in recent decades have killed trees on poorly drained soil. (See "When a Tree Falls in the Woods," May-June 2020.) "We've got 150-plus acres of really nice mature Big Woods forest that died off and is not going to come back," says Ed Quinn, DNR Parks and Trails natural resource program supervisor. As on the North Shore, at Nerstrand, park managers are drawing on species they wouldn't have planted a generation ago, such as silver maple and Dutch elm disease�resistant elm. They are native to the general area, but not to Nerstrand specifically. Says Quinn, "We're trying to reestablish a native community, but not the one that was there before."
         The idea of transitioning to a new forest, of introducing species or genotypes that were never or rarely found on a site, of taking seeds from distant sources can be unsettling to some of the people who manage parks, scientific and natural areas, and other sites that operate under a goal of preserving a slice of the pre-settlement landscape. Says Quinn, "So many of us who have been in this field for decades — our touchstone was always pre-European settlement conditions. Those were the reference sites. That's what you looked at and said, OK, that's what we're trying to restore."
         "What should our new goals for restoration ecology be, in light of the fact that replicating historical conditions is no longer going to be possible?" asks Cornett of The Nature Conservancy. "I would describe that as a real crisis of confidence in some ways for ecological restoration and restoration ecologists, because we've often used these historical references to guide our work."
         Interest in climate adaptation might be even keener among county, state, federal, and tribal foresters with "a multiple-use mindset" than among park managers, says Stephen Handler, climate change specialist for the Forest Service Northern Research Station and Northern Institute of Applied Climate Science. For managers of working forest land, manipulating a forest for specific objectives is everyday work. "In many cases it's a lightbulb moment when people realize some of the practices we already consider as smart forest management are perfectly in line with climate change adaptation," he says.
         Foresters have a range of strategies for dealing with climate change. The most conservative is "resistance" — as Kueper explains, "looking for places like climate strongholds and places where we don't expect there to be as drastic a change because maybe it's a protected microclimate." Some of the planting on the North Shore is a good example. In Chippewa National Forest, foresters are thinning red pine stands to leave remaining trees with more soil moisture. A bit more aggressive is "resilience", says Kueper. "Resilience is really about promoting forest health and recovery from disturbances. And to do that, we might have to tweak the forest ecosystem as it is, and that might look like increasing the diversity of tree species that are present at the site and making sure that we're incorporating more species that are going to be climate winners, that are more resilient against the future climate." Again, the North Shore parks provide a good example. Another is found in Minnesota's black ash swamps, threatened indirectly by climate change as warmer winters have allowed the emerald ash borer to spread in the state. Says Kueper, "Our big concern in forestry is that eventually this insect is going to find its way to north-central Minnesota where we have a million acres of black ash swamp across our state forest lands and kind of wreak destruction and havoc there." State foresters have employed a resilience strategy in an ash swamp near Warroad in northwestern Minnesota. They recently planted a mix of not-quite-native-to-the-site red maple, silver maple, bur oak, swamp white oak, and black spruce so that when most of the ash die, the site persists as a forest.
         The most far-reaching and controversial method of forest adaptation is "assisted migration". Species may be moved hundreds of miles, completely out of their native range, to new areas where they are expected to flourish in a warmer climate. Assisted migration has been avoided by Minnesota state foresters and the crews working on the North Shore parks partly out of caution and also because DNR policy was only recently changed to allow forest managers to plant more southerly genotypes and species. Says McCarthy, "You have a little more flexibility now, but we still want to do it carefully. And you want to monitor your results and not apply it broadly until you know how it will turn out."
         In some cases, assisted migration aims to save endangered plant species that are isolated and threatened with extinction as climate becomes unsuitable in their native range. A good example is the endangered yew Torreya taxifolia, known as "the rarest conifer in North America." It survived only in tiny areas of Florida and Georgia until the volunteer Torreya Guardians transplanted specimens to sites throughout the Appalachians and Midwest, as far north as southwestern Wisconsin.
         Assisted migration can also involve moving common species to new locations — not to protect individual species but to diversify a forest and help it thrive under changing conditions. Among the research leaders is the Cutfoot Experimental Forest in the Chippewa National Forest in north-central Minnesota. "This is the largest assisted migration experiment in Minnesota for sure, likely in the [Great] Lakes states and beyond," says Brian Palik, research scientist for the U.S. Forest Service. The 3,000-acre experimental forest is dominated by red pine stands that grew in the wake of fire a century ago. Researchers have been looking at silvicultural practices such as thinning, and mixing in different species in the understory to determine what might succeed in a warmer climate. "Novel species" from more southerly reaches, such as white oak, bitternut hickory, and black cherry "are going like gangbusters," says Palik. Seedling survival after six years is nearly 100 percent.
         One of the wildest experiments has been finding a potential replacement for the red pine itself. It is Minnesota�s state tree, and red pine stands, such as those at Itasca State Park, are beloved. Nonetheless, the species is vulnerable to drought and, according to some models, will shrink away to the northeast. "The worst-case scenario is that red pine doesn't do well in the future," says Palik. "We thought, what's a potential alternative that is similar ecologically, economically, and culturally? Ponderosa pine may be it."
         Yes, Ponderosa pine. In Minnesota. The closest native population is in the Black Hills. "That," says Palik, "is truly assisted species migration." Ponderosa pine looks nearly identical to red pine. (In fact, Scottish botanist David Douglas originally misidentified it as red pine.) Ponderosa pine is suited to warmer, wetter winters and hotter, drier summers, both predicted in northern Minnesota. "They grow better than anything else that we planted," says Palik.
         Tribal and industry foresters in particular have been interested in bringing in species from surrounding areas, says Palik. The Leech Lake Band of Ojibwe has expressed interest in more oak because acorns are valued as a traditional food, he says. And the timber industry places high value on Ponderosa pine and black cherry in their native ranges.
         Whether Ponderosa pine ever finds a significant foothold in Minnesota is up in the air. What is not in question is that Minnesota's forests will be changing, either as a result of die-off and regeneration, or because forest managers anticipate and facilitate a new assemblage of species. Either way, there's no standing still. As Palik says, "The climate of southern Minnesota has been in northern Minnesota for at least 20 years."
  • "Conservation strategies for the climate crisis: An update on three decades of biodiversity management recommendations from science", by B.C. McLaughlin et al., April 2022, Biological Conservation
    EXCERPTS: 3.3.2. Climate-adaptive assisted migration. 'Climate-adaptive assisted migration' included the practices of assisted gene flow, defined as the intentional movement of organisms or gametes between populations within species' current distributions (Aitkin and Whitlock, 2013), and assisted species migration, defined as the intentional movement of species beyond their historical range limits into areas that have or are projected to become climatically suitable (Peters and Darling, 1985). Recommendations for climate-adaptive assisted migration increased from 7% to 12% of papers in the second time period, yet these recommendations frequently were tempered by recognition of potential challenges. In the first time period, a large majority focused on plants in forest systems in North America. In the second time period, just over a third related to plants and the remainder included corals, invertebrates, mammals and birds. Consistent with trends in the full data set, the specificity of recommendations increased — concept papers dropped from over half to less than a third, and more papers modeled or mapped specifically where to move species. Authors expressed near-universal concern about the disruptions that assisted species migration could cause to non-target organisms in recipient ecosystems... Because of these concerns, most authors presented assisted species migration as appropriate only for species under exceptionally high threat from climate change, as a form of 'extreme conservation.'
         ... The increase in recommendations for assisted migration occurred in the context of a broader shift away from polarized debates around this strategy toward more nuanced analyses (e.g. Hallfors et al., 2017, Skikne et al., 2020).
  • "US proposes experimental populations of endangered species outside historic habitat", by Edvard Pettersson, 6 June 2022, Courthouse News Service.
    EXCERPTS: The proposed rule change will remove a requirement that experimental populations must be reintroduced in a listed species' historic range.... The U.S. Fish and Wildlife Service said Monday it wants to introduce experimental populations of endangered or threatened species outside these species' historical habitats where climate change and invasive species have made those habitats unsuitable. In what the agency said was the first Endangered Species Act interpretive rule produced under the Biden-Harris administration, the proposed change will remove the requirement that experimental populations of listed species are to be reintroduced in their historic range.
         Under today's proposed revisions, the Service would be able to introduce an experimental population of an ESA threatened or endangered species into suitable habitat outside of its current range and probable historical range.

       FWS Press release quote by Secretary of the Interior Deb Haaland:

    "Climate change and the rapid spread of invasive species pose an ever-increasing threat to native biodiversity. The time to act — and use every tool at our disposal — is now.... The growing extinction crisis highlights the importance of the Endangered Species Act and efforts to conserve species before declines become irreversible. This effort to update proven conservation tools will help ensure species on the cusp of extinction can recover and thrive for generations to come."

    NOTE: A report on this ESA rule change published in Audubon Magazine incorporates the term "assisted migration."

  • "Bibliometric Analysis of the Structure and Evolution of Research on Assisted Migration", by Lahcen Benomar et al., June 2022, Current Forestry Reports.
    ABSTRACT (excerpts): Purpose of Review - Assisted migration is increasingly proposed as a proactive management strategy to mitigate the consequences of maladaptation predicted under climate change. Exploring the social and academic structure of the field, its research gaps, and future research directions can help further the understanding and facilitate the implementation of assisted migration strategies. Here we used bibliometric analysis to examine the intellectual, social, and conceptual structures of assisted migration research to identify gaps and opportunities for future research. Bibliometric data based on publications on assisted migration were collected from Scopus and Web of Science databases using assisted migration and climate change or their synonyms as queries. Metadata were merged, processed and several networks were constructed.... Summary - We conclude that future research is expected to concern mainly the assessment of physiological response of species and populations to extreme climate events such as drought and frost, and the contribution of non-climatic factors and biotic interactions in local adaptation and population performance under climate change. Social core hubs distinguished in this work can be used to identify potential international research and training collaborators necessary to address gaps and challenges underlying assisted migration implementation.

    EXCERPTS: Among the various strategies that have been proposed to manage species under climate change, assisted migration (AM) is a proactive conservation and restoration strategy that aims to limit species' maladaptation by facilitating gene flow and transfer of genetic material that may be adapted to the climate of the recipient environment. AM, also called "assisted colonization," "managed relocation," and "assisted gene flow" is defined as the intentional movement of species or populations to regions predicted to be suitable under future climate conditions.... Bibliometric analysis can assist in identifying research gaps and individuals active in collaborative networks required for this work. Bibliometric analysis involves a set of quantitative explorations that aims to provide insight into the evolution of a given discipline, detect research gaps, and describe the collaborative structure between academic institutions or countries.... This study showed that much of the research on assisted migration has been carried out in North America, where Canada and the USA have established strong collaborative networks. Canada�USA collaborations have emphasized research related to assisted migration of populations for forest trees, compared to other research categories ... Overall, this bibliometric analysis points towards the need to establish new, long-term experiments that expand international col- laborations and foster development of interdisciplinary toolkits to fill existing and evolving knowledge gaps that are important to assisted migration and its application to conservation and restoration.

  • "Tree species in one of the world's most diverse conifer forests not migrating uphill fast enough", by Cal Poly Humboldt, 17 August 2022, Phys.Org News.
    EXCERPTS: The trees in NORTHERN CALIFORNIA'S KLAMATH MOUNTAINS are not keeping up with climate change. Instead, many tree species are in decline, losing the race due to climate warming and decades of fire suppression. A new study by researchers at Cal Poly Humboldt, the University of Wyoming, and the U.S. Forest Service and published in Ecological Monographs found that trees in an extraordinarily diverse mountain wilderness in Northern California have been inching their way to higher elevations over the last half-century, but not fast enough to keep up with climate warming.

    The Klamath Mountains are a biodiversity hotspot, home to the richest assemblage of conifer species in the world, but climate change and fire suppression threaten the future of this region.

    Using data first collected by two Humboldt professors John Sawyer (Botany) and Dale Thornburgh (Forestry) in 1969, contemporary researchers retraced their footsteps by resampling the same plots nearly 50 years later. They found that most tree species are barely starting to shift to higher ground, likely in response to climate warming. But that migration was far slower than expected given the degree of warming over the last half-century. Most tree populations are declining, and the persistence of rare species is in question.

    Lead researcher, Humboldt Biology Professor Erik Jules, says the climate has warmed significantly since the 1969 study. The summer temperatures of today's forest, at any given elevation, are similar to what would have been found 1,000 feet lower during that initial research. "Sawyer and Thornburgh's work from 1969 provided a treasure trove of data for understanding how forests have changed during a time of rapid warming and drying," says Jules.

    "One of the most thrilling parts of this project was when we tracked down two field assistants and former Humboldt students who worked with John and Dale, and they mailed us Kodak slides from their time in the mountains in 1969," says Melissa DeSiervo, a former Biology graduate student at Cal Poly Humboldt and now a postdoctoral research associate at the University of Wyoming. "From the photos, we could see we were pitching our tents in exactly the same places the researchers camped nearly 50 years ago! Our ability to detect changes in the forests of the Klamath Mountains has been greatly enhanced by the careful work of this previous generation of ecologists."

    While tree species in other parts of the world have moved upslope much faster, the ponderosa and sugar pines and other conifers in the Klamath Mountains have only moved an average of 37 feet upward in the following years — a small fraction of the 1,000 feet they would need to be living at the same temperature as they did in 1969.

    So why are trees in Northern California moving more slowly? Researchers believe that the suppression of wildfire is at least partly responsible. Fire used to be a natural and frequent component of the forest environment, even in the cooler, high elevations of the region. Most tree species in the area are tolerant of low and even moderate severity fires, and some are dependent on fire for successful establishment, taking advantage of the forest canopy gaps created and maintained by fire.

    "Fire naturally promotes drought- and fire-tolerant species. But fire suppression over the last century paved the way for the growth and expansion of white fir, a species less tolerant of fire and drought," says Matthew Reilly, a former researcher at Humboldt and now a research forester with the U.S. Forest Service. In fact, white fir is crowding out other tree species, in particular the large, old fire- and drought-resistant pines that are declining in abundance.... "The changes that have occurred since 1969 have resulted in a less resilient forest that may not be able to adapt to continued climate change, and one that could be severely damaged from an intense wildfire" says Jules.

  • "Forests can't adapt to climate change fast enough. So humans are trying to help", by Hanna Hett, 30 August 2022, Canada's National Observer.
    EXCERPTS: As climate change raises the Earth's temperature, trees — which are highly adapted to specific climates — are now trying to survive in environments too warm for them to thrive. In most parts of B.C., it is already about 1.5 C warmer than it was in 1945. With over 300 million trees planted in B.C. every year to replace what has been logged or lost in wildfires and other natural disasters, there's an opportunity to help forests adapt to climate change. This summer was the first time the province's Ministry of Forestry made it mandatory that every single tree planted must be adapted to warmer climates.
        Traditionally, reforestation companies collected local seeds in the area they planned to reforest. But these seeds are genetically adapted to past climates and are already suffering from climate change. Now, they use seed sources from climates about 2 C warmer than their reforestation site. The extra 0.5 degrees, O'Neill says, will mean the trees are adapted for a climate that is expected in about 15 years. It's a balancing act: they have to plant trees that will survive in the current climate and that will also do well in the future. Still, this "assisted migration" of trees is only happening in the portion of B.C.'s forested land base reserved for timber harvesting. This means forests not slated for logging are left to deal with the impacts of climate change naturally.
  • "Pac NW's 'trees of life' are dying. Now we know why", by Nathan Gilles, 18 August 2022, Columbia Insight. (Cross-posted 31 August 2022 in The Register-Guard newspaper, Eugene OR).
    TAGLINE: Drought and climate change are wreaking havoc on an icon of Pacific Northwest forests. How long do the western redcedars have?

    EXCERPTS: ... They grow as understory trees for much of their lives, but they can also stretch to the forest overstory, reaching heights of up to 200 feet. They're a key part of Pacific Northwest ecosystems, though they rarely dominate the forest, often living alongside firs, hemlocks, alders and maples. These trees are the Pacific Northwest's iconic western redcedars (Thuja plicata).

    To many indigenous peoples, who used the trees for houses, clothes, weapons, tools, medicines, art and canoes, they�re known as The Tree of Life. They've been recorded to live for over 1,500 years. But these trees are now dying.

      For at least a decade, struggling and dead western redcedars have been reported throughout the Pacific Northwest. But the cause and extent of the dieback (a condition in which a tree or plant begins to die from the tip of its leaves or roots inward) have long remained unknown.

    Now we have the answers. The dieback is widespread, and the cause appears to be climate change. What's more, we now know that the dieback could be the beginning of the end for the species in many parts of the Pacific Northwest.

    Earlier this year, scientists from the Oregon Department of Forestry, the Washington Department of Natural Resources and U.S. Forest Service published the results of a two-year study on the dieback. The study concludes not only that the cedar dieback is happening throughout Oregon and Washington, but also that the dieback is not the result of a biotic agent — such as a fungi or insect attack — but due to climate, namely the decades-long drought affecting Oregon and Washington.

    Columbia Insight was given a copy of the official report for the study ahead of publication by the project's lead scientists. The study's results are also available online on a public website.

    Now a second, yet-to-be-completed study from Washington State University is arriving at similar conclusions.

    While the government report falls short of saying climate change is killing western redcedars, the public website refers to the drought as "climate change-induced." But by far the most interesting climate change connection in the report and on the website is a reference to previous research that predicts the range of the western redcedar will change significantly as temperatures rise throughout this century. The website speculates, "We could be seeing the range of WRC [western redcedar] shift or shrink due to changing conditions that reduce the suitability of some sites for this species."

    ... In western Oregon and Washington, researchers observed dieback at lower elevations — in Oregon in the Willamette Valley and in Washington in the urban corridor running from Olympia to Puget Sound. By contrast, in the tree's distribution in eastern Washington, dieback was observed throughout the tree�s elevational range. "What we're seeing is probably true to what most [scientific] models that have been developed [have predicted], though it's obviously not going to be exact," says Melissa Fischer, forest entomologist and lead researcher on the dieback for the Washington State Department of Natural Resources and coauthor of the official report.

    ... Both sets of researchers found signs of fungal and insect damage, but only on some not most of the trees experiencing dieback. Western redcedars contain a number of anti-pest compounds, one of the reasons the trees are prized as a building material. That the trees showed signs of biotic attacks at all was a bit surprising and is itself an argument for drought-induced stress, according to the researchers. "They [biotic agents] are secondary," says [Betsy] Goodrich [U.S. Forest Service]. "They come in when the tree is stressed. So, it does point more to stress than a biotic damage agent."

    ... So far, the project [Western Redcedar Dieback Project, directed by Joseph Hulbert, a researcher at Washington State University] has planted trees from Oregon in three Washington cities: Seattle, Tacoma and Renton. But, says Hulbert, this effort is just a pilot project and was not designed to be scientifically rigorous but intended to be used as an educational tool in schools....

    Editor's note: Read another article on Western Redcedar dieback: Has this iconic Northwest tree reached a tipping point?, by Nicholas Turner, 30 October 2022, Seattle Times.

    Editor's note: See also the "2 Billion Trees" project page of Natural Resources Canada for this project: "Resilience of western redcedar to climatic extremes (drought)".

  • "The Forest Service Is Experimenting with Relocating Tree Species To Save Them from Climate Change", by Nathan Gilles, 15 September 2022, Columbia Insight.
    TAGLINE: 'Assisted migration' has come to the Pacific Northwest, but experts don't agree if it's a good thing or a radical response to a warming world.

    EXCERPTS: ... Assisted migration is the idea that because the climate is steadily warming, trees can — and, some argue, should — be moved from where they currently grow to where they are predicted to grow in the future. This, the idea goes, will introduce trees better adapted to tolerate climate-induced warming and droughts.

    While decades of research into assisted migration have provided proof of concept, these past experiments have tended to be small and far more controlled. Unlike the neat, tightly packed rows of little trees grown in highly controlled conditions, [Andrew] Bower's seedlings [of Douglas-fir planted in the Gifford Pinchot National Forest of southern Washington State] are spaced 17 feet part in exactly the sort of chaos foresters face when replanting after a disturbance, such as a harvest or a wildfire. (Bower has another experimental site even further north, in the Okanogan-Wenatchee National Forest where he's planting ponderosa pines in a section of the forest that burned during the 2014 Carlton Complex fire.) Testing in disorderly real-world conditions is the point.

    Bower's experiment is one of the first of many planned in the coming years by the Forest Service to see if the agency can put years of scientific research into assisted migration into operational practice.

    ... In the years and decades to come, Bower expects to see clear differences between the locally sourced trees and the migrated trees. "One scenario is that the local seed lots do better to begin with because they are adapted," says Bower. "And maybe the seedlings from the warmest [climes] suffer from frost damage now, but over time as things warm up we start to see a shift where the productivity of the local seed lot decreases and those seedlings that are more adapted to warmer temperature do better."

    If the climate predictions the Forest Service is using prove accurate, by the middle decades of this century (2041-2070), the Willamette National Forest seedlings [Oregon] should be perfectly adapted to their current location [Washington]. While by the end of this century (2071-2100), the Siuslaw National Forest seedlings [central Oregon coast] will find their current location matches their evolved needs. The lower elevation seedlings should be adapted in matter of years. The local seedlings are being used as a control.

    ... Earlier this year, researchers from the Forest Service and states of Oregon and Washington published the results of a multi-year study concluding that the Pacific Northwest's iconic western redcedars [Thuja plicata] are dying due to climate change.

    ... Further south, California's beloved coast redwoods could lose the southern half of their range as early as 2030, according to scientists. California's giant sequoias and Joshua trees are also threatened by climate change.

    ... Plants, according to multiple studies, simply cannot migrate fast enough to keep up with the rate of change. Trees — being long-lived perennials that often take years if not decades to get to productive age — are expected to be especially vulnerable to climate change.

    Assisted migration essentially lends a helping human hand, moving trees fast and far enough to keep up with the rate of climate change. However, assisted migration is not without risk. Move trees too soon and they also risk environmental mismatch, or "maladaptation." Move trees from warm locations to cold ones and the cold can sometimes do them in. Move trees from dry climates to wet ones and novel fungi will end their lives.

    Assisted migration, say its critics, is ethically fraught. If widely adopted, they say, it would entail a massive reordering of the natural world and could lead to unintended consequences. What's more, because one tree's current home is another tree's future home, saving one species could mean sacrificing another.

    The City of Seattle is currently experimenting with assisted migration, including a small experiment to see if western redcedars can be replaced with nonnative incense cedars. Seattle isn't alone. Other groups are experimenting with assisted migration.

    ... In April of this year, the Portland-based Bonneville Environmental Foundation (BEF) released the results of a similar survey of individuals doing ecological restoration for local nonprofit, federal, state, municipal and tribal organizations in the Pacific Northwest. While also small, just 51 individuals responded, the survey further confirmed that assisted migration is already happening regionally, including planting native plants that were grown from seeds outside their range and planting (or planning to plant) nonnative species, including incense cedar, giant sequoia and coast redwood.

    ... Bower's two sites are part of the Forest Service's Experimental Network for Assisted Migration and Silviculture, or ENAMS project, an ambitious effort spanning Forest Service operational and research offices in Washington, Oregon and California. The Washington Department of Natural Resources and Oregon Department of Forestry, which are also running experiments in assisted migration, have joined in the effort, as has the Bureau of Land Management. The Forest Service also plans to work with private landowners.

    As of this writing, ENAMS has planted trees on three sites, including Bower's two and an additional site in the Umpqua National Forest in Oregon. Two more Oregon sites, both in the Willamette National Forest, are scheduled to be planted this fall. But this is just the beginning. An additional 15-20 sites are expected to be planted by 2024. The overwhelming majority of sites are on lands affected by wildfires.

    "This is intended to be very big and all encompassing," says Robert Slesak, research forester at the Pacific Northwest Research Station and project lead. "The science is important but one of the most valuable things that could come out of it hopefully is that we are forming a foundation to get a shared purpose to work together collaboratively on this issue because it's huge."

    It would be hard to overestimate the impact the ENAMS trials could have on forestry in the Pacific Northwest. To date, regional foresters have been cautious about embracing assisted migration, believing that "local is best" when it comes to selecting seeds. "We're starting to move on this [assisted population migration], to match seed sources with the climate to which they are adapted to the climate to which they will be experiencing," says Brad St. Clair, a retired (though still very active) former USFS research geneticist with the Pacific Northwest Research Station.

    St. Clair has been a leading advocate for assisted migration in the Pacific Northwest. He's also run some of the longest and most involved studies in assisted migration in the region. This has involved, to put it bluntly, torturing trees, moving trees from one climate to another and seeing what happens.

    What St. Clair and his colleagues discovered is that trees tend to tolerate climates that are either 2 degrees Celsius (3.6 degrees Fahrenheit) warmer or 2 degrees C cooler than the climate they evolved for. "The climate has changed by 1 degree Celsius [roughly 1.8 degrees Fahrenheit] so far and we are looking at 2-3 degrees C [3.6-5.4 F] by another couple decades," says St. Clair. "It's going to look bad. So, we need to start moving now or we aren't going to have any chance of keeping up with it."

    To address this rapid change, St. Clair, Slesak and Bower are recommending the Forest Service should reassess its "local is best" practice and embrace assisted migration. Specifically, they're hoping to change guidelines around "seed zones." Existing within a tree's larger range, seed zones are the Forest Service's way of describing what are, in effect, climate varieties, trees of the same species that form genetically unique populations based on adaptations to climate.

    ... What St. Clair, Slesak and Bower are recommending isn't so far-fetched. Very similar rule changes about where seeds can be collected and planted have already gone into effect in Canada. In 2019, the British Columbia Ministry of Forests changed its rules around its "seedlot" selection system — B.C.'s version of seed zones — to incorporate climate change and assisted migration. On April 1 of this year, the Ministry of Forest's chief forester made using the new rules obligatory. Greg O'Neill, climate change adaptation scientist for the British Columbia Ministry of Forests, outspoken advocate for assisted migration and project lead for the Ministry's Assisted Migration Adaptation Trial (AMAT) says he's pleased to see the rules change.

    ... Assisted migration has critics. "Quite frankly, it [assisted migration] seems to be a recipe for driving ecological simplification," says Mark Schwartz, plant ecologist and professor emeritus at the University of California Davis. In 2012, Schwartz was the lead author on a paper in the journal BioScience outlining potential problems with assisted migration. Calling themselves the Managed Relocation Working Group ("managed relocation" is another term for assisted migration), Schwartz and 31 coauthors detailed the ethical, ecological and even political problems that could arise from assisted migration. Problems include: a lack of clear policies and laws around assisted migration; the possibility that the practice could lead to "severe negative ecological consequences"; and the possibility that assisted migration poses a "moral hazard," because people might think it's a solution to climate change, which could discourage efforts to lower emissions and slow global warming.

    The paper also points to how assisted migration tends to "privilege a species-centered approach to conservation," one that tends to focus on single dominant species, like trees, and just a handful of dominant trees at that. "We shouldn't be comfortable with saying that we need to change the dominant tree species, and everything will be okay," says Schwartz. As an example, he says, consider what would happen if people started moving coast redwoods in large numbers out of their current range in northern California and southern Oregon further north into northern Oregon and southern Washington. Doing this, says Schwartz, would only move the trees not the whole ecosystem. The bay trees that live in the forest understory, the fungi that live in the soil, the salamanders that swim in the water that collects on the forest floor and all the other organisms and complex interactions that make up the forest would be gone, an ecology simplified. "What kind of redwood forest would that be if it succeeds?" says Schwartz. "It might be a very impoverished redwood forest because we haven't brought in the hundreds of things that fill in around the redwoods."

    The critique is a valid one. The Forest Service ENAMS trials involve just two dominant tree species: Douglas-fir and ponderosa pines. Though Slesak says he hopes to expand the number of species in the future. O'Neill's AMAT project includes 15 species. However, missing are many of the understory trees, including vine and big leaf maples. What's more, the attention afforded the 15 species isn't distributed equally. Seeds for Douglas-firs come from 11 seedlots, whereas only 2 seedlots are used for western redcedar.

    In general, says B.C. forester O'Neill, research dollars tend to go to dominant tree species, which often are dominant timber species as well. While O'Neill and the Forest Service's research has clear applications beyond timber production, timber production could certainly benefit from adopting assisted migration and for a very obvious reason: trees, at least in theory, could be harvested before they become maladapted due to climate change. Trees could keep up with the rate of change by being cut down.

    On the other hand, trying to use assisted migration to restore an ecosystem in which trees will not only not be cut down but will be expected to live for decades if not centuries, and hence will need to endure the long years of climatic mismatch, is another story altogether. "If you're not planning on harvesting, then the assisted migration is more complicated, because you will expect trees to last longer than 60 or 70 or 80 years," says O'Neill.

    ... [Re: The "Stossel Creek" project east of Seattle] The Stossel Creek site is an experiment in using assisted migration for ecological restoration. A land that was partially logged, the 154-acre Stossel Creek site was purchased by Seattle City Light in 2015 as part of its efforts to restore salmon and steelhead habitat in the area. About a third of the site is being actively restored, though only a small part using assisted migration. Using methods similar to Bower's, the Stossel Creek site includes seedlings representing six local trees species but migrated from sites further south, an example of assisted population migration. Trees include Douglas-fir and western redcedars.

    The site also includes an example of species migration. Incense cedar seedlings from California were planted at the site. Incense cedar is being investigated as a "surrogate" — meaning ecological replacement — for the climate-imperiled western redcedar. Incense cedars were selected when the project was unable to locate western redcedar seedlings from California. While the site's plot of incense cedars is small, the site's operators, Ronda Strauch [Seattle City Light] among them, are in effect experimenting with replacing a local species threated by climate change with a non-local species. This has some concerned.

    "The common consensus is that western redcedars aren't going to make it. And so, yeah, people are already replacing the species," says Brenda Clifton, senior restoration botanist for the Skagit River System Cooperative, which oversees natural resource management for Sauk-Suiattle Indian Tribe and the Swinomish Indian Tribal Community. Clifton isn't a member of either group and does not claim to speak for them. Without naming any one project, Clifton says she worries that, because the western redcedar is experiencing a major climate-induced dieback, people are rushing to replace the species when they should be working harder to protect it. "For me, replacing the western redcedar is problematic," says Clifton. "It's an iconic species and certainly has its niche, and I would worry that if you go too gung-ho and try to fill that niche with a species from somewhere else you might advance the decline of the western redcedar."

    Strauch says this is oversimplifying the situation. "I don't think incense cedar is going to replace western redcedars," says Strauch. "But that's part of the experiment, to see how incense cedars are going to do right next to western redcedars. If for some reason people don't want that species [incense cedar] on the site, we can always go in and cut them down.

    ... Dr. David Shaw, professor and forest health specialist at the Oregon State University in the College of Forestry and another critic of assisted migration, also thinks more attention should be paid to local genetic variability. "I believe our native forests represent biodiversity hotspots," says Shaw. "My big contention is, since we don't know where climate change will take us, ultimately, that we should look for local seed sources and drought tolerance — because we may have it here, we just don't know because we haven't looked." Echoing Schwartz, Shaw says the assumptions underlying assisted migration tend to simplify or overlook the complex interactions that occur in healthy undisturbed forests. He thinks assisted migration, even the least controversial and risky assisted population migration, is selling local genetic diversity short. Trees that have survived climatic disturbances like droughts should be sought out and their seeds collected, he says. "In some evolutionary theory," says Shaw, "disturbance actually increases the resilience of the forest because it kills the trees that aren't adapted to the disturbance and leaves the ones that are. As disturbance comes in and causes a lot of mortality, the question is what do the survivors represent?"

  • OPINION, Guest Essay: "Humans Have a Long History of Making 'Very bad Decisions' To Save Animals", by Tim McDonnell, 16 September 2022, New York Times.
    EDITOR'S NOTE: This opinion essay entails a range of high-tech methods for conserving the biodiversity of endangered animals. The cautionary statements made are very appropriate for animals — but when the concept of "assisted migration" is later reported for plants, a whole field of far less risky opportunity opens up for poleward movements of plants native to that continent and for the achievements already documented in, what is termed, "urban biodiversity arks". Excerpts that highlight the PLANT perspective are included below:

    EXCERPTS: ... "You might argue there's no such thing as a natural system anymore," he [biologist Brad Shaffer at UCLA] said. "I'm looking out my window on an urban forest, and I don't think a single tree is native." Up to now, these infiltrations have occurred by chance or accident. But, in the future, Mr. Shaffer thinks they could be part of an intentional design.

    As natural habitats diminish, he argues, scientists should consider relocating some endangered species into "urban arks." After careful study of potential conflicts with native species (including people), nonnative species could be released in cities to reside in parks and backyards, on rooftops and window ledges, and in water bodies. From there they could take their food and shelter from natural resources and infrastructure that, as Mr. Shaffer wrote in the journal Nature, "although built for humans, happens to also fulfill the nonnative species' ecological needs." Endangered birds and trees could be good candidates for this kind of deliberate "assisted migration" (snakes, maybe not so much: "People don't like them," Mr. Shaffer, a herpetologist by trade, says).

    At the least, he says, nonnative species already living in urban areas without causing undue harm to native species should be protected as "in-situ conservation colonies," not eradicated as pests.

    The concept of an urban ark also speaks to a principle that Ms. Shaw [Rebecca Shaw, chief scientist of the World Wildlife Fund] says is crucial to effective conservation, no matter what form it takes. We need to break down the artificial psychic barrier, she says, between people and wildlife that causes us to think of nature as "something you go to, instead of something you are a part of."

    Climate change ensures that there are few if any species left on Earth that aren't feeling the effects of human activity. Well-intentioned meddling in ecosystems is now unavoidable in many cases, and has the potential to forge a new, mutually beneficial covenant of protection between "us" and "them."

  • "Trees can't outrun climate change. Should humans give them a lift?", by Elisabeth Weise, 21 September 2022, Phys.Org News. Also published in USA Today, but it is behind a paywall there.
    EXCERPTS: ... "We're anticipating Mother Nature would migrate the red spruce northward," [David] Saville said. "We're just accelerating that." He is one of hundreds of foresters, arborists, scientists and researchers working to give species like the red spruce a lift north to outrun a climate that's changing faster than they can keep up with. Although still somewhat controversial, as the extent and speed of temperature rise becomes clear, such "assisted migration" is increasingly being contemplated.

    "The goal," said Tony D'Amato, a professor of forestry at the University of Vermont, who's overseeing the experiment, "is to help them deal with these really unnatural conditions that don't have an analog in the past."

    With a warming climate, insect devastation and habitat destruction, as many as 1 in 6 U.S. tree species outside of Alaska are threatened with extinction, a study published last month found. They include the Torrey pine of California, Arkansas's maple-leaf oak, Georgia's Franklin tree, American chestnuts and the East Coast's black ash. Those trees evolved to be adapted to the climates in which they originally grew, said Brad St. Clair, an emeritus research geneticist who worked for decades in the forest service's Pacific Northwest Research Station in Corvallis, Oregon. Historically the migration rate for trees is between 650 to 1,300 feet a year, he said. "To keep up with climate change, it's going to need to be about 10 times that," he said. By the end of the century, mossy, rainy Portland, Oregon, is predicted to look more like Redding, California, which is dry and sweltering in summer. "Plant populations aren't going to be able to keep up."

    After more than 30 years of discussion in the U.S. forestry community, multiple trials are now underway to test how well assisted migration works and whether it disrupts existing ecosystems.

    Helping tree species get to more hospitable climes, sometimes also called managed relocation, simply means planting them in climates to which they're genetically suited. It's just that their native climate has changed, said Gerald Rehfeldt, a forest geneticist who published some of the first papers on the topic in the 1990s.

    While the climate hasn't radically changed yet, projections show by mid-century it will be a much bigger problem, St. Clair said. "We have to do something now if we are to have any hope of keeping up with it," he said.

    The idea of playing God with species, moving them farther north than they'd naturally get on their own in time, is controversial. A central belief of the environmental movement has been that nature should be left alone as much as possible — human tinkering, however well-intentioned, can too easily go wrong. "The red flags go up," said Forest Service geneticist Jessica Wright, who is planting test reforestation sites up and down the West Coast. "It's something that needs to be done with a lot of consideration. You're opening a Pandora's box."

    ... Many argue there's no such thing as "natural" at this point. Humans have introduced tremendous change by burning fossil fuels since the Industrial Revolution began in the 1750s, said Cuauhtemoc Saenz-Romero, a research biologist at the University of Michoacana de San Nicolas de Hidalgo in Mexico. "The forests cannot follow their natural cycles because we now have 420 parts per billion of CO2 in the atmosphere," he said. "The normal level is 260."

    Increasingly, the mainstream forestry community sees assisted migration as a necessary tool as the planet warms.

    Wright hopes her test plots of seedlings will provide insight into how trees in California, Oregon and Washington will fare toward the end of the century. While 80 years is a long time for humans, it's the blink of an eye for many tree species. "We're substituting space for time," she said. Such efforts are meant to give the trees a chance, not to change the face of the forests. "We're moving populations within a species range," she said. "It can't be, 'Let's plant Joshua trees in Oregon."

    In Vermont, D'Amato wants it made clear no one's talking about replanting entire forests. "We're just trying to introduce a few of these trees so that 50 to 100 years from now we'll have some seed-producing individuals adapted to the change that can sustain the forest moving forward," he said.

    Sometimes the work is not to move but simply save species for a time when they might be reintroduced in a new, more favorable home. An international network of arboretums is working to act as lifeboats for threatened species. In Chicago, the Morton Arboretum has planted specimens of two threatened oak species from the South, the maple-leaf oak and the Georgia oak, in case they become even rarer in their current homes because of warming temperatures. "We're trying to be proactive in the sense that we want to plant the species that will be well-adapted to these future climate change scenarios," said Silvia Alvarez-Clare, the arboretum's director of global tree conservation.

    Without intervention, a species might slowly move northwards a few hundred feet a generation. "Now it's happening so fast, there's not even one or two generations for the trees to adapt," she said.

    While arborists in the United States are cautiously testing these ideas, in Canada's westernmost province, assisted migration is now law. In April, the province of British Columbia made it mandatory that tree replanting on logged provincial land be done according to climate. Previously, the seedlings had to come from the same general area. Now they come from as far as 250 miles south. The province replants 300 million seedling trees a year on logged land. "You want to get your seed from where it's 3.8 degrees warmer now, because we need to recognize there's already been 2.7 degrees of climate change that's occurred in the last 80 years," said Greg O'Neill, the province's climate change adaptation scientist.

    It's not just trees but entire ecosystems that are at stake. Take the beloved monarch butterfly. For millions of years, the iconic insects have made an epic 2,500-mile journey from Canada to Mexico. There they overwinter in mountainside forests of Abies religiosa, called oyamel in Spanish and sacred fir in English. Today, the trees at lower elevations are struggling. "The rainy season now starts one month late, and what is worse, ends one month early," said Saenz-Romero. In part because of this habitat loss, the monarch was added this summer to the International Union for Conservation of Nature's "red list" of endangered species.

    A pilot project in Mexico is trying to help. In the Monarch Butterfly Biosphere Reserve, a UNESCO world heritage site 80 miles west of Mexico City, Saenz-Romero is planting sacred fir seedlings higher up the sides of dormant volcanoes where it's cooler. He wants to see if the trees, and the monarchs that depend on them, can better survive there. His research found that moving the trees 1,300 feet up the mountain — the equivalent of a 3.6-degree cooler environment — kept them healthy. The unanswered question is whether the monarchs will move to the new forests. "We hope," said Saenz-Romero. "We pray."

    EDITOR'S NOTE: In this very informative and wide-ranging article, there was one paragraph that is an unfortunate carry-forward from the past:

    "There are plenty of examples of the best intentions going awry. The Tree of Heaven, imported from China as a popular landscaping tree, became invasive across much of North America, even secreting a chemical toxic to nearby plants. The glossy privet crowds out native species in the eastern U.S. The Bradford pear, originally brought from Asia in the 1960s, is so invasive several states have banned its sale."
    All those examples are exotics from another continent. "Assisted migration", in contrast, as it has been proposed for decades, is entirely poleward movement ON THE SAME CONTINENT. For trees in eastern North America, the Pleistocene glaciations forced movements hundreds of miles southward, aggregating "novel communities" along the way. Assisting SAME-CONTINENT northward migration now is best understood as restoration of range conditions for "deep-time natives".

  • "Portrait of a Forest on the Climate Edge", by Jessica Leber, Fall 2022, Audubon Magazine.
    EXCERPTS: ... Land and wildlife managers across Minnesota's boreal zone are actively thinking about how to build resilience into ecosystems to help them withstand stresses from insect invasions, extreme weather, and warming temperatures, as well as help tree and animal species move and adapt. For example, in 2021 unusually severe drought-fueled wildfires burned in Superior National Forest. Conservationists and scientists there have been monitoring the regrowth. In one experiment using a strategy called assisted migration, the Nature Conservancy this summer worked with officials to reforest some trees that they hope will be able to tolerate a hotter future.

    At Beltrami Island State Forest, located on the state's drier western boreal edge, one of several adaptation strategies is increasing tree species diversity within and among forest stands. "If we lose one species, at least we'll still have a forest," says Charlie Tucker, a wildlife supervisor at the Minnesota Department of Natural Resources Division of Fish and Wildlife. Tucker and his colleagues have already singled out several climate-sensitive birds, including Spruce Grouse and Boreal Chickadees, they are actively managing and monitoring at Beltrami Island. The grouse there live in highest densities in the area's thick jack pine forest, where they eat conifer needles, but these habitats may transition to thinner woodlands as the climate dries. "If jack pine does not regenerate as well under drier scenarios, then this will not bode well for Spruce Grouse in this area. We suspect they are already experiencing a northward range contraction, but data are lacking — other than anecdotally," he says. Conversely, while there are no Kirtland's Warblers at Beltrami Island State Forest currently, in the future, there may be plenty of woodland habitat that is suitable for them, he says. Managers there are also doing experiments with timber harvest patterns in parts of the state forest to see how to best help birds that may be vulnerable.

  • "Potential for Assisted Migration of Coast Redwood (Sequoia sempervirens) to Vancouver Island: Problems and Prospects", by Richard S. Winder, Anais Valance, Ian Eddy, Vince Waring, and Alessandra Jones, October 2022, Report BC-X-459, Natural Resources Canada. Note: Direct DOWNLOAD for Researchgate members.

    ABSTRACT: Climate change threatens coast redwood (Sequoia sempervirens) within the extent of its current range along the western coast of North America, from southern California to southern Oregon. We examined the potential for assisted migration of coast redwood to the western coast of Vancouver Island as an adaptation strategy to counter climate threats. While many coast redwood trees have been planted successfully throughout the Pacific Northwest, a question remains concerning the ability of the species to establish successive generations of seedlings in this region. We first plotted potential optimal habitat for self-sustaining populations of coast redwood on Vancouver Island using several key factors, including optimal annual fog frequency (> 200 h), optimal elevation above sea level (20-300 m), aspects not facing and adjacent to the ocean, optimal mean spring temperature (>6C) and optimal biogeoclimatic zone. Within this optimal habitat, we also plotted the variation in three relevant parameters: mean annual precipitation, mean summer humidity, and cumulative annual frost-free days. This resulted in a prediction of narrow strips of optimal habitat along the central west coast of Vancouver Island, wherein the best environmental trade-offs were located midway along coastal inlets.... The potential for recruitment of coast redwood planted in this region appears to increase with increasing temperatures; contemplating assisted migration of sustainable populations would therefore involve considering the influence of future warming. These considerations are complicated by unknowns in the future behaviour of shifting ocean currents in the region as it warms, and their impacts on atmospheric temperature and fog formation in the region. Modelling these factors with increased resolution, establishment of field trials, and assessment of the social context and acceptability of moving this species would improve our understanding of the potential for assisted migration of coast redwood to Vancouver Island.

    EXCERPTS: INTRODUCTION: The purpose of this document is to explore the potential use of assisted migration (AM) to extend the range of Sequoia sempervirens (D. Don) Endlicher (coast redwood, coastal redwood, or California redwood) northward to the Pacific Rim of Vancouver Island. Coast redwoods are well-known to be among the largest trees and are an important endemic component of forests occupying coastal zones in California and southern Oregon. However, the International Union for Conservation of Nature (IUCN) has designated this tree species 'endangered', with its current habitat reduced due to past logging and facing the threat of further human encroachment (Farjon and Schmid, 2013). As the Earth's climate changes, warmer temperatures and associated droughts are also threatening habitat in the current native range of the tree (Brunhuber, 2015; Earle, 2020). While the specific response of mature coast redwood trees to climate change is uncertain (Carrol et al., 2014) and the climate tolerance for many species often extends beyond their current fundamental niche (Bocsi et al., 2016), there is ongoing concern for conservation of the species as climate change proceeds. Assisted migration of coast redwood provenances is an adaptation strategy that might help counter the potential impact of climate change and loss of habitat (Libby, 2017).

    Plant species have the natural capacity to disperse into new habitats and adapt to change, but ongoing climate change is so rapid that many species are unable to naturally keep pace (Aitken et al., 2008). AM has been used by humans since historical times but is only now being considered as a deliberate forest management tool to counter the effects of climate change, albeit not without challenges and controversy. Risks and problems to consider include potential invasiveness of the translocated species, disease introduction and exposure, differences in soil environments (pH, soil biota, etc.), proportional differences in climate parameters (temperature and precipitation ranges and extremes), differences in herbivory, etc. AM may involve the human-assisted movement of provenances to more suitable habitat within the native range of a species (assisted population migration, APM), translocation just beyond the current range (although possibly within the historic range) of the species (assisted range extension; ARE), or migration to a point well beyond the current range (assisted long-distance migration; ALM). APM carries the lowest risk for unexpected or undesired outcomes and is usually considered in the context of managing commercial forest species. ARE is also considered within a forestry context but may involve slightly increased risks and challenges while ALM is a method employed as a 'last resort' method for conserving endangered species as it involves higher risks and challenges (Winder et al., 2011). AM of redwood has been proposed as a potential method to conserve this species (Mandel, 2015; Libby, 2017; O'Hara et al., 2017). The strategy might also contribute to sustaining the productivity of coastal BC forests as climate change progresses (Artz, 2010; Mandel, 2015) for other declining species such as yellow cedar (Cupressus nootkatensis) (Buma et al., 2016; Comeau et al., 2019).

    This report will focus on the prospects of using ARE [Assisted Range Extension] to extend the range of coast redwood northward in a changing climate regime, along with the associated issues. Our specific objectives were to use known habitat characteristics to map areas of Vancouver Island where ex-situ conservation of self-sustaining coast redwood populations might be possible in a changing climate, and to test the ability of Vancouver Island soils to support germination of S. sempervirens seedlings. The latter is an important aspect of successful ex-situ conservation, where a complete life cycle (from seedling recruitment to full-sized trees at maturity) is required. Natural recruitment proceeds in a forest environment where competition, pests, and other selective pressures are extant. We hypothesized that the germination of coast redwood seeds would be reduced in soil with relatively low organic content (within the range of soils existing on Vancouver Island), colder temperatures, and higher sodium and magnesium salt concentrations....

    COAST REDWOOD HABITAT: Coast redwood is a North American conifer famed as one of the world's tallest tree species. It is currently distributed in a narrow (ca. 8-56-km wide) band of coastal areas that extend almost 725 km from just south of 46 N latitude in Big Sur, California to just north of 42 north latitude in the very southern portion of coastal Oregon, normally not more than 30 km (up to 80 km) from the Pacific Ocean (Fig. 1). A Late-Holocene disjunct population may have existed as far north as the central Oregon coast (Gavin et al., 2013). Until recently, old-growth coast redwood forests covered approximately 70,000 ha within their native range. Less than 5% of that amount remains after extensive logging and clear-cutting, much of it as homogeneous, dense, and even-aged stands (Lalemand, 2018). The extensive decline in habitat leaves populations of this species vulnerable to further losses. Unfortunately, there are concerns that coast redwood may also be declining within its range due to climate change and associated changes in fog regimes (Brunhuber, 2015; Earle, 2020). While cone and seed production is abundant in the northern part of the range, it is more variable elsewhere (Olson et al., 1990; O'Hara et al., 2017), and trees in the southern part of the range tend to be clustered in canyon bottoms susceptible to disturbance (Lorimer et al., 2009). Dynamic range models based on climate variables generally predict attenuation of the southern portion of the range with a concomitant expansion to the north in warmer, drier climates. DellaSala et al. (2015) have used climate models to project a 21% loss of habitat supporting baseline distribution for the species by the 2050s. Fernandez et al. (2015) developed models incorporating historical climate trends that generally project contraction of suitable climate in the southern portion of the species range and expansion towards the north in anomalous (warmer and/or drier) climates, with some relatively stable areas (refugia) also occurring within the range. Hargrove (2016) modeled several climate scenarios for coast redwood that also generally follow the trend of a northward shift. In addition to all these concerning trends, the requirements for coast redwood to reach future climate refugia may present significant challenges (Roberts and Hamman, 2016).

    CURRENT RANGE CONSTRAINTS: In the current epoch, higher elevation and mountainous terrain, which are above fog decks where habitat may be increasingly xeric and characterized by serpentine soils (Zinke et al., 1986), limit eastward distribution of coast redwoods. While fires can be damaging to coast redwood in the northern part of its range, the species nevertheless copes with natural fire regimes in this region (Viers, 1980; Olson et al., 1990). Zinke et al. (1986) point out that serpentine soils east of coast redwood habitat in southern Oregon limit spread in that direction. The species is also sensitive to cold temperatures and frost (Snyder, 1992) which poses another challenge to northern expansion. Competing vegetation could theoretically constrain range limits; however, coast redwood is classified as a shade-tolerant, dominant climax species. Within its range, it coexists with Douglas-fir (Pseutotsuga menzesii) — a tree that is also dominant throughout the coast of the Pacific Northwest (Olson et al., 1990). With potentially optimal terrain in much of coastal Oregon being a relatively narrow region between the Pacific Ocean and mountainous terrain, we theorize that this coastal corridor would allow disturbances such as storms, fire, and floods to have a relatively strong influence on northward spread, in effect constituting a 'bottleneck' terrain. For example, tsunamis and storms periodically inundate the lowest seaward elevations, exposing prime areas for northward expansion to salt water. Likewise, fires, winter storms, and other natural disturbances might block or slow expansion further inland along this confined area. However, there is evidence that a disjunct population of coast redwood existed further north along the Oregon coast (Fig. 2, Table 1) during the recent epoch (late Holocene) either as a relict community or the result of long-range movement of propagules (Gavin et al., 2013).

    CLIMATE: Redwoods are thought to be a relict species, a holdover from more diverse and widespread Mesozoic conifers. Since then, their distribution has changed considerably in response to changes in climate. During the Paleocene and Eocene Epochs (6.5-3.8 x 107 y bp), they reached their widest and northernmost distribution, mixing with other conifers and ranging up 60 N latitude (Florin, 1963, Snyder, 1992). There is evidence of S. sempervirens occurring in Alaska, Eurasia, and Greenland. Cooler, drier temperatures during the Oligocene and Miocene (38-6 x 106 y bp) accompanied a shift southward, until coast redwoods reached their present location during the Pliocene Epoch (Snyder, 1992). One study suggested that drought-induced limits to CO2 availability might have been a factor involved with this range contraction (Quirk et al., 2013). Lack of drought tolerance has also been noted as a limiting factor in the post-glacial rebound in the distribution of conifer species in general (Elias, 2013).

    FOG: The current core habitat of coast redwoods is characterized by cool summer temperatures and high humidity from fog. The occurrence of summer fog may be more important than precipitation in delineating habitat because the area is also defined by the occurrence of summer droughts (Snyder, 1992). Fog interception is a key source of water for coast redwoods since it decreases water loss through evapotranspiration (Dawson, 1998; Burgess and Dawson, 2004; Simonin et al., 2009. In fact, coast redwood trees absorb as much as 40 percent of their water directly from coastal fog — an adaptation necessary in taller trees where transpiration stress might otherwise limit growth (Dawson, 1998; Burgess and Dawson, 2004; Simonin et al., 2009).

    California's coastal fog has decreased significantly over the past century, associated with a decrease in atmospheric moisture and a lifting of the cloud deck(O'Brien, 2011). These changes have the potential to affect the entire coast redwood ecosystem (Hamilton, 2013), given that a cool coastal temperature regime and warm interior is one of the defining characteristics of California's coastal climate. Using a network of 114 temperature stations along the Pacific Coast, Johnstone and Dawson (2010) found that the coast-inland temperature contrast associated with fog has decreased substantially, not just in Northern California, but along the entire U.S. coastline (Sanders, 2010). Redwoods also depend upon deep, moist soils or ground water provided by rainfall during winter rainfall events. Mature coast redwoods are therefore unlikely to die outright with decreased fog, but there could be less recruitment of new trees, which would lack necessary water, high humidity, and cooler temperatures.

    OTHER EXCERPTS: ... Currently, coast redwoods occupy a range and habitat that generally includes irregular NW to SW ridges and deep, narrow valleys, with principal streams draining NW. The terrain is generally rough and steep, divided by both major streams and smaller drainages. Coast redwoods are distributed from approximately 0 to 915 m elevation (mostly 30-760 m). Growth of the largest trees occurs on flats and benches along the larger streams, on wetter coastal plains, river deltas, moderate westerly slopes, and valleys with seaward openings. Drier zones are less optimal for growth and seedling viability (Olson et al., 1990).

    Soils are also an important component of coast redwood habitat. Distribution is sharply delimited by inland changes in bedrock and associated serpentine soils inhibitory to growth (Zinke et al., 1986). Areas directly adjoining the Pacific Ocean are also not necessarily favourable, as soils may accumulate deleterious concentrations of sodium and magnesium, and salt spray may cause foliar damage (Snyder, 1992; Wu and Guo, 2006). Within coast redwood habitat, predominant soils include Xerochrepts, Haploxerults, and Haplohumults (Hugo, Josephine, Melbourne, Empire, Sites, and Larabee series, orders Inceptisols and Ultisols), along with alluvial soils derived from these; the soils originate from consolidated or soft sedimentary rocks. The Hugo soil series (Typic Distrochrept, order Inceptisols) predominates in the natural range (Olson et al., 1990). Within coast redwood habitat, moisture ranges between 18-86% of soil storage capacity (62% being optimal) (Olson et al., 1990) and equivalents of replaceable calcium are reported to range from 4-80 or more, with 63 being optimum (Zinke, 1964; Snyder, 1992). Coast redwood does not grow well on soils with high amounts of magnesium and sodium.

    The aspect of coastal terrain is another factor that may constrain coast redwood habitat. Although most habitat borders the ocean, the species does not tolerate strong winds and is reported to be sensitive to salt spray carried inland during storms (Olson et al., 1990, Wu and Guo, 2006). The soils of areas proximate to the ocean may also lack sufficient depth and fertility. With increasing altitude and slope, and decreasing moisture, coast redwoods have a smaller stature and other tree species begin to predominate. Habitat occurs in all aspects of terrain in its northern range, where the trees reach maximum growth and development. In the southern range of coast redwoods, its occurrence is limited to western or northern aspects; at the southern extreme the species almost exclusively occurs on narrow canyon floors in foothills adjacent to the ocean. At canyon mouths, the trees exposed to onshore winds frequently have flat tops with dead windward limbs — effects attributed to desiccation (Haasis, 1933). Coast redwoods reach their maximum size on alluvial flats where flooding generally limits competing species, resulting in nearly pure redwood stands (Olson et al., 1990).

    VANCOUVER SLAND AS POTENTIAL FUTURE HABITAT: ... In this study, we considered habitat with a potential future climate similar to the contemporary climate of coastal California. We focused on coastal Vancouver Island, as it possesses the most optimal fog and temperature regimes for the growth of coast redwood. The North Pacific Seasonal Sitka Spruce Forest (NPSSSF) occupies the hypermaritime zone along the Pacific Rim on Vancouver Island. Sitka Spruce (Picea sitchensis), the dominant or co-dominant tree species in this zone, can be associated with other conifers, including western hemlock (Tsuga heterophylla, often co-dominant), western redcedar (Thuja plicata), Douglas-fir (Pseudotsuga menziesii), shore pine (Pinus contorta) and yellow cedar (Cupressus nootkatensis), usually within 25 km of the Pacific Ocean (NatureServe, 2022).

    Fog is also an important feature of the NPSSSF; it ameliorates the effect of summer droughts and therefore would be critical to recruitment and survival of coast redwoods. On Vancouver Island, maximum fog frequency occurs along the west coast, due to occurrence of a semi-permanent oceanic high-pressure cell (Fig. 4). Maximum fog frequency occurs during summer months (Pincock & Turner, 1955; Environment Canada, 2015). Diurnal fog also occurs, driven by daily temperature contrasts between air and water, fluctuating with daily heating and cooling. (Environment Canada, 2015). Coastal Vancouver Island also experiences advection fog, related to the movement of atmospheric waves ('stratus surges') that develop along the California coast and move northward along coastal Oregon and Washington to the west coast of Vancouver Island. (Environment Canada, 2015). Models also indicate a parallel increase in ocean upwelling and associated fog that may mitigate increased summer drought. However, current trends indicate a decrease in fog levels (NatureServe, 2022). The unknown future balance of summer drought intensity vs. fog intensity in this area may be an important caveat for any attempts to perform assisted migration of coast redwood in this region. If drought impacts increase along the Pacific Coast more generally, or if increased ocean upwelling and fog increases or maintains cooling and continues to favour Sitka Spruce forests rather than coast redwood, migration efforts may face barriers from both technical and conservation perspectives.

    The mean annual temperatures found in most areas in Vancouver Island are colder than the 10-16C range reported for current coast redwood habitat (Fig. 5). However, many species tolerate ex situ climates well outside their current niche; in situ temperature ranges may therefore be less suitable for modelling projected ranges (Bocsi et al., 2016). As there are many examples of coast redwood growing in the Pacific Northwest, it may be that mean annual temperature is a landscape characteristic of current habitat not directly responsible for biological limits to growth and survival. Considering the results of the germination experiment presented in section 6.3, the requirements of self-sustaining coast redwood populations might more directly involve mean spring temperatures above 6C, as there was little germination detected at that temperature.

    While winter rainfall is abundant in the NPSSSF, there is very little in the summer (Wolf et al., 1995). Climate models for the area suggest that summer precipitation may decrease in this zone; this decrease could provoke shifts in vegetation in the region (NatureServe, 2022). Figure 6 illustrates the distribution of mean annual precipitation (mm) on Vancouver Island. We estimated that the most optimal habitat for coast redwood would occur in areas with moderate to high mean annual precipitation, which includes most of the western coast of the island but would exclude areas on the southwest coast southeast of the Jordan Plateau (the southwestern tip of the island). Snow falls during northerly Arctic outflow events, but accumulation is generally light along the west coast. Exceptionally, winds over water can pick up increased moisture and lead to more snowfall. This can be considerable when outflow winds move across the Strait of Georgia to the southern end of the Insular Mountain Range (Environment Canada, 2015).

    ... Natural recruitment of seedlings is a key life-cycle attribute that could be impacted by soils. Natural recruitment of coast redwood would be critical to completing the life cycle of the tree in a recipient habitat and maintaining sustainable populations without ongoing human intervention. There are anecdotal reports of natural recruitment occurring in coast redwoods planted at several sites in the Seattle, Washington area, although the degree of recruitment is uncertain due to confounding factors such as basal sprouting, 'guerrilla planting' by individuals, and deer browsing (Connie Barlow, Pers. Comm., 2020). The extent to which natural recruitment might be successful in this region is thus still unclear.

    To map potential habitat for self-sustaining populations of coast redwood on Vancouver Island, we overlayed several climatic, terrain, and ecological datasets to identify areas with optimal potential habitat using R software (R Core Team, 2020) and the 'Raster' package (Hijmans, 2022). A 500-m digital elevation model (DEM) was used to generate aspect and elevation layers. Recent climate data (2000-2010) from ClimateNA (Wang et al., 2016) were also incorporated as layers in the model. We digitized a coastal fog-hours map and rasterized it, along with the Biogeoclimatic Zones of British Columbia, using the 500-metre DEM as a template. Consequently, the minimum mapping unit of the analysis was 25 ha. The environmental parameters described below were chosen to define and map the bounds of potential habitat on Vancouver Island.

    We included areas of Vancouver Island experiencing 200 cumulative hours of fog or more.... The North Pacific Seasonal Sitka Spruce Forest occurring in this hypermaritime zone only extends 0-350 m above sea level (NatureServe, 2022); we therefore used 300 m above sea level as a conservative upper elevation limit for fog occurring within this zone. Areas lower than 20 m above sea level were excluded due to the potential for coastal flooding during extreme weather.

    ... Areas likely to be exposed to winds carrying salt spray aerosols were also excluded from habitat.... Accordingly, areas were excluded from potential habitat if they were within 5 km of the coast, and below 55 m elevation with a south- to west-facing aspect (the direction of prevailing onshore winds).

    ... Rapid establishment of root systems in moist soils during relatively abundant springtime precipitation and warmer spring temperatures is therefore a key factor for recruitment. Per the discussion in Section 4.3.5., soils in Coastal Western Hemlock very wet maritime (CWHvwm), or very wet hypermaritime (CWHvwh) BGC zones have the most humid soils in the region. Areas not in these BGC zones were excluded from potential habitat. Moreover, from our findings in germination experiments mentioned in Section 6, germination of coast redwood seeds is minimal below 6C. We therefore excluded areas from habitat if their mean springtime (March-May) temperature during the past 10 years was less than 6C.

    Figure 8 [ABOVE] shows 233,400 ha of coastal Vancouver Island matching all of the above criteria. This area would be our best estimate of potential habitat for establishment of self-sustaining populations of coast redwood. The mapped areas do not necessarily equate to current habitat in all respects. Differences in the previously discussed parameters will require further evaluation with field trials to understand how they may or may not limit growth and recruitment. Moreover, environmental parameters may improve or become more constraining as climate change proceeds. Evaluation of spacing, provenance, timing of planting, thinning, pest control, type of planting stock, competing vegetation, etc. would be necessary to truly refine this model.

    Figure 9 shows a close-up map of the area containing potential habitat, wherein the current status of three important climate variables is shown on continuous scales. Mean annual precipitation is included for its impacts on soil moisture. Mean summer humidity is included for its correlation with summertime fog and amelioration of summer drought. 'Cumulative annual frost-free days' is an included parameter because increased frost frequency and colder temperatures would indicate longer periods of below-optimal conditions for seedling germination and growth. While the range of variation in these three parameters may not preclude the growth of coast redwood in the selected area, they would nevertheless serve as useful guides to consider in any selection of future test sites.

    ... Recruitment of migrated coast redwood populations may be relatively insensitive to different soil types on Vancouver Island, but it may be significantly reduced in colder temperatures. Temperature regimes may have to be warmer than current seasonal norms to ensure successful recruitment in migrated coast redwood populations.

    DISCUSSION and CONCLUSIONS: Coast redwoods have been successfully planted throughout the Pacific Northwest (Figs. 2-3, Table 1). But can these trees complete their life cycle in this extended range and establish self-sustaining populations? The results of the seed germination experiments suggest that areas located within the fog zone of the western coast of Vancouver Island could provide habitat that would support natural recruitment, especially in a slightly warmer climate. Although exposure to sodium and magnesium cations is reported to be a limiting factor for redwood growth, the germination experiments did not establish salt exposure or soil type as a critical limitation to seed germination. Concerns about exposure to these salts may be more pertinent for later growth stages, or there may be other interactive factors such as soil pH or phosphorus concentration (Zinke et al. 1986), genotype (Wuo and Guo, 2006), or other parameters that could affect sensitivity.

    With regard to self-sustaining populations, a salient point is the ability of coast redwood trees to regrow via stump resprouting. It is possible that migrated populations could be sustained via this mode of vegetative regeneration in the absence of seedling recruits. On the other hand, resprouting leads to a highly aggregated stand structure with sprouts clustered near older stumps (O'Hara et al., 2017). Limited recruitment via seedlings in the current range already represents a limit to dispersion capacity (O'Hara et al., 2017). Reliance on resprouting to maintain and sustain populations in the long term would be a constraint on further dispersion, genetic diversity, and adaptation of the species.

    ... Increases in temperature, changes in ocean currents, and the current trend of reduced fog could lead to a decline of endemic species in the area [Vancouver Island], one that could be ameliorated through AM of more southern provenances or species such as coast redwood. On the other hand, severe reductions in fog might also limit recruitment of coast redwood seedlings.

    [FINAL PARAGRAPH}: Setting aside the question of self-sustaining populations, it is already clear that coast redwood plantations can be established in the Pacific Northwest. Even so, data is still needed concerning suitability and mortality, competition with endemic flora, compatibility with soil microflora, and pest interactions within this region. The establishment of common garden trials per the suggestion of O'Hara et al. (2017), including translocation trials along Vancouver Island's Pacific Rim, would help to further understand those factors, along with climatic constraints on growth and recruitment. This would be particularly important if the regional climate change produced ca. 5C warmer springtime soil temperatures, shifting mean annual temperatures from the lower end of the optimal growth range and potentially improving natural seedling recruitment by warming soils. Understanding the social context and acceptability of moving this species is also something that would need to be examined. Managed plantations are a potential venue for ex-situ conservation of the species and offer a way to study the potential for assisted migration efforts to conserve the species in the Pacific Northwest.

  • "Last Resort: Moving Endangered Species in Order to Save Them", by Zach St. George, 27 October 2022, Audubon Magazine.
    EXCERPTS: ... Recently, though, Fish and Wildlife proposed a revision to its regulations that would allow it to move species beyond their historical range, calling this a "necessary and appropriate" step in response to the twin threats of climate change and invasive species. With increasing numbers of species at risk of extinction, says Tim Male, founder of the nonprofit Environmental Policy Innovation Center, "we may need this tool a lot more often." The ability to move species beyond their historical range would be a small change on paper, but one that both supporters and opponents of the revision say could significantly impact American conservation

    ... While Congress offered no limits on where the agencies might establish experimental populations, stipulating only that they must be physically separate from "non-experimental," or wild, populations of the same species, Fish and Wildlife provided limits of its own. In regulations it adopted in 1984, the agency restricted itself to establishing experimental populations only within a species' "probable historic range."

    "Historic range" was both ill-defined and Eurocentric, in a country where written records extend back less than six centuries, but where human history — and ecological impact — extends back tens of thousands of years. It also took a static view of the living world, seeming to assume that the past range of a species represents that species' ideal range. This view was at odds with the fossil record, which showed that the arrangement of species is continually in flux, especially during times of climatic change. It was also increasingly at odds with the reality of climate change in the present.

    Since at least the 1980s, scientists have debated the merits of a very specific type of translocation called "assisted migration" (and sometimes "assisted colonization" or "managed translocation"), which aims to conserve species by moving them to climatically suitable places outside of the range that they currently or recently occupied. Some scientists argued that habitat destruction would make it impossible for many species to keep up with the pace of climate change, and that without human help those species could face extinction. Others, pointing to the destruction wrought by invasive species, maintained that moving species to new habitats as a conservation method was too risky.

    Decades later, despite hundreds of academic papers and countless media reports on the topic, though, there are relatively few real-world experiments in assisted migration. Scientists have moved butterflies, lichens, and rock lobsters, along with a handful of other creatures. A group of private citizens planted the endangered Florida Torreya, an evergreen in the yew family that is native to riparian areas in Florida and Georgia, far to the north, throughout the eastern United States. A number of timber companies, state and federal forestry agencies, and tribes in the U.S. and Canada have moved trees, most of them common species.

    ... In 2018, Fish and Wildlife began to consider changing its regulations, and this past June it published its proposal to remove the words "historical range" from its regulations on experimental populations.

    The proposed rule drew more than 500 comments. Many were critical of the proposed changes, calling them unnecessary or misguided, suggesting that they would allow the service to release endangered species — and the laws and regulations they bring — nearly anywhere in the country. Some were concerned about the possible reintroduction of wolves and other predators, noting that the wolves that Fish and Wildlife reintroduced into Yellowstone and parts of the Southwest in the 1990s have killed ranchers' cattle and sheep. Other commenters echoed longstanding arguments against the use of assisted migration, suggesting that translocating creatures carried too much risk of unintended consequences.

    Ben Novak, lead scientist at Revive & Restore, a nonprofit focused on using cloning, gene editing, and other genetic technologies in conservation, says that fears that new experimental populations might turn into invaders are overblown. While translocated species have caused ecological disasters — as when people brought cane toads from Hawaii to Australia, for example, or introduced Indian mongooses to the West Indies — nearly all of those species were translocated for economic or cultural reasons, not as part of conservation efforts, Novak says. Last year, Novak and his colleagues published a paper analyzing the purposeful translocations of more than 1,000 species in the U.S. over the last 125 years as part of conservation efforts. They found only one conservation translocation — of a fish — that resulted in the loss of significant biodiversity.

    In the late 1980s, Fish and Wildlife moved 200 endangered watercress darters from its native Black Warrior River drainage, near Birmingham, Alabama, into Tapawingo Springs, 15 miles northwest. But Tapawingo Springs, it turned out, was home to another rare species, the rush darter, which was only described as a species in 1998. By 2001, the now-thriving population of watercress darters had wiped out the spring's population of rush darters (although the species persists elsewhere). Such mistakes are rare, Novak says. "I actually think ecologists have a strong history of making predictions. We can do this well."

    In its proposal, Fish and Wildlife did not make an explicit connection between its proposed ability to establish experimental populations outside of species' historical ranges and the decades-old debate over assisted migration. But evolutionary geneticists Janna Willoughby and Avril Harder did, in a comment they submitted to Fish and Wildlife with other members of the lab that Willoughby leads at Auburn University. The biodiversity crisis means regulators "need to seriously consider conservation actions that are currently deemed too extreme," Harder said. Willoughby agreed: "What we think is extreme today may be common in a fairly short time period."

    Mark Schwartz, a conservation scientist at University of California, Davis who was an early skeptic of assisted migration, said that it's hard to say exactly what effect Fish and Wildlife's rule change will have on conservation efforts. On the one hand, he said, the relative dearth of assisted migration experiments may be due less to the current legal barriers and more to a lack of scientific and societal consensus on the practice, making wildlife managers reluctant to use it. On the other hand, he said, I do think the lack of policy has hindered experimentation, in that it is often not an option on the table because of a lack of policy that permits it." ...

  • "Europe's beech forests threatened by climate change", by Directorate-General for Environment, 26 October 2022, European Commission (News: Environment).
    EXCERPTS: A new study finds that climate change could significantly reduce beech trees' growth across most of the continent this century. Forest dieback may follow, the researchers warn. Beech forests in Europe have far-reaching benefits. Like many other forests, they provide important habitat for wildlife and contribute to the water and carbon cycle. Beech forests are also economically important as a source of timber and are socially valued as spaces for recreation. This new pan-European study predicts that climate change will reduce these benefits by restricting the growth of beech trees (Fagus sylvatica L.) in most European countries. Previous studies have shown the effects of climate change on beech trees, but only at a regional level. The study provides a large-scale analysis, encompassing the full range of the species in Europe.... The data revealed that climate change has already affected tree growth in Europe. Beech tree growth fell by up to 20% in southern Europe during 1986-2016, compared with 1955-1985. Northern areas were not affected in the same way, however. Growth increased by 20% in Norway and Sweden, for instance. ... Separate research has reported that declining growth is a precursor of dieback. Thus, as well as reducing the value of Europe's beech forests, these losses could also signal the death of vast areas of forest. The most vulnerable sites are at the southern edge of the species' range, in Mediterranean countries, the study indicates. The researchers conclude that immediate action is needed to adapt forests to climate change and to develop sustainable management strategies, and that forest managers should consider the study's results in long-term silviculture plans.
  • "Researchers hoping to give the American chestnut tree a leg up on climate change", by Paula Moura, 14 November 2022, WBUR Radio.
    EXCERPTS: As the earth warms and the precipitation patterns change, trees are expected to migrate north seeking weather they are adapted to. Scientists project trees will need to move faster than their natural abilities through seed spreading. That's led some scientists at the University of Vermont to try to jumpstart this process for an already beleaguered tree: the American chestnut.

    "We're simultaneously trying to restore the chestnut in our experiment, as well as testing how well it will perform in a future environment if moved a bit farther north," said Peter Clark, the study�s lead researcher.

    After a blight fungus decimated American chestnut trees across the eastern U.S. in the mid-20th century, dedicated naturalists have kept the species alive by breeding hybrids of the American chestnut with the Chinese chestnut. It's those hybrids that researchers at the University of Vermont are using in an experiment of "assisted migration" — the process of planting seedlings outside their traditional habitat in an effort to give them a head start on climate change.

    Four years ago, Peter Clark and his team planted over 900 two-and-three-year-old seedlings in New Hampshire, north from the chestnuts' historical range. "We were really surprised that the American chestnut showed this incredible capacity to grow and persist, even in these extreme cold environments," Clark said. In his study, out of nine tree species that were transplanted, the chestnuts ranked second in growth and survival. It doesn't mean it was easy for the chestnut hybrids — they grew fast in the spring, but cold snaps injured their roots in the winter. Still, over time, more than 400 chestnuts continue to grow. "They'll potentially serve as a really important source for the future establishment of chestnuts in that region," Clark said.

    It's too early to know for sure if assisted migration works, but scientists expect to learn more in about two decades. The group at University of Vermont is part of a large network of researchers studying tree migration called Adaptive Silviculture for Climate Change. Courtney Peterson, a researcher at Colorado State University, coordinates over a dozen sites in this program that are testing what kinds of human interventions can help trees be more resilient in the future. She thinks studies of assisted tree migration like Clark's will be key to learning how to manage forests with climate change. "On-the-ground knowledge and expertise is going to be crucial as we're making these management decisions moving forward," Peterson said.

    Scientists collaborate with forest managers to design these studies to be as close to replicating a natural setting as possible so that managers can apply the lessons learned, said Tony D'Amato, professor of silviculture and forest ecology at the University of Vermont and one of the authors of the chestnut assisted migration study. He also pointed to the importance of human assisted migration in the past, when Indigenous peoples helped spread chestnut seeds that formed the original American chestnut range. "The bigger movement historically would have been on Indigenous people just given how important it was to their culture for food staple."

    While the researchers are hopeful that the chestnut hybrids take root in northern climates, the reality is these trees are considered functionally extinct. Chestnuts can reproduce in the wild when the trees are near each other. But wild American chestnut trees very rarely reach maturity; the blight keeps them from growing to their full potential. On a recent fall day in Weston, John Emery, the local chapter director for the American Chestnut Foundation, points to a gangly, thin chestnut tree just about 2 feet tall with a section of scraped off bark. "When young male deer in the fall rub their antlers on the bark, that creates an opening for blight fungus to come in," he says. Besides the blight, deer are one of the biggest threats to the tree. In addition to the bark scraping, the deer eat the green tops of the seedlings. To tackle this problem, he uses deer spray and mesh nets. Emery and other volunteers planted around 6,000 chestnut trees in the orchard in effort to breed blight-resistant chestnut tree hybrids. Still, usually less than 5% of the hybrids inherit enough resistance to be good candidates for further breeding. To identify the blight-resistant trees, they deliberately apply the fungus. Then they breed the hybrids from the surviving trees by hand pollinating.

    Emery supports all efforts to restore chestnuts to the environment, including human-assisted climate migration. "The squirrels and the blue jays only move chestnuts as much as a mile a year. And that isn't really very fast compared to climate change."

  • 2022: Operationalizing forest-assisted migration in the context of climate change adaptation: Examples from the eastern USA, Brian J. Palik, Peter W. Clark, Anthony W. D'Amato, Chris Swanston, Linda Nagel, October 2022, Ecosphere
    ABSTRACT EXCERPT: ... While forest-assisted migration (FAM) has been discussed conceptually and examined experimentally for almost a decade, operationalizing FAM (i.e., routine use in forest conservation and management projects) lags behind the acceptance of the need for climate adaptation. As the vulnerability of forest ecosystems in climate change increases, FAM may need to become an integral management tool to reduce long-term risks to ecosystem function, despite real and perceived barriers for its implementation. Here we discuss the concept of operational-scale FAM and why it remains a controversial, not yet widely adopted component of climate adaptation. We present three case studies of operational-scale FAM to illustrate how the practice can be approached pragmatically within an adaptation framework despite the barriers to acceptance. Finally, we discuss a path toward advancing the wide use of operational-scale FAM.

    EXCERPTS: Climate change may represent the greatest challenge ever faced by forest managers, conservation biologists, and ecologists, with already realized and projected impacts that include changes in forest productivity (Bottero et al., 2017) and tree habitat suitability (Peters et al., 2020), catastrophic tree mortality, and altered pest behavior (Bentz et al., 2010).

       ... Concepts, policies, and decision-making frameworks for use of FAM [forest-assisted migration] have been reviewed extensively over the last decade (e.g., Park & Talbot, 2018; Pedlar et al., 2012; Williams & Dumroese, 2013), with potential outcomes of FAM primarily explored with modeling (e.g., Duveneck & Scheller, 2015; Gray & Hamann, 2013), or inferred from examinations of provenance trials spanning a range of climate conditions (e.g., Aitken et al., 2008). Until recently, however, there have been few published examples that illustrate how to incorporate FAM into climate change adaptation strategies at sufficiently large, operational scales that are translatable to forest conservation and management strategies (Clark et al., 2021; Etterson et al., 2020; Muller et al., 2019; Young et al., 2020). A lack of operational-scale implementation of FAM, where we define operational as the practice being applied in actual forest management projects, rather than strictly in a research setting, likely reflects the inexperience of forest managers and conservation biologists with the concept, a belief that FAM carries too high a risk (Findlater et al., 2021), a perceived lack of social license to pursue FAM broadly (Neff & Larson, 2014), and strong adherence to the precautionary principle (Ricciardi & Simberloff, 2009). Given that many forests are at risk or have already fundamentally changed (e.g., Allen et al., 2010), FAM may nevertheless be an essential tool for climate adaptation to insure against change and with lower long-term risk to ecosystem vulnerability.

    ... There is also a growing recognition that climate adaptation in forests must expand beyond a focus on maintaining timber production capacity to be inclusive of maintaining a broad range of ecosystem services (e.g., D�Amato, Jokela, et al., 2018; Rissman et al., 2018). It is therefore unlikely that these objectives can be met without greatly increasing the use of FAM, which likely will also require increased communication and cooperation between research scientists and forest managers to achieve the desired aims for FAM. ... Our goal in this article is to show how FAM can be incorporated into climate change adaptation strategies in managed forests in ways that will facilitate informed use and generation of best practices by foresters and conservation biologists. Our specific objectives include (1) examining the role of FAM in the context of a range of climate change adaptation strategies and (2) highlighting examples of operational-scale use of FAM in adaptation demonstrations in the eastern United States, specifically in the Northwoods of Minnesota and in New England. We focus on this region as it represents the most forested region in United States and is already experiencing the impacts caused by climate change (Swanston et al., 2018). Additionally, well over 40 tree species are forecasted to decline from or migrate into this region (Iverson et al., 2019), further underscoring the potential need for best practices in FAM to be developed and operationalized.... Examples can be found at, searching by the keyword "assisted migration." ... We highlight three case studies of FAM that were implemented in ways to address and overcome, to varying degrees, the barriers of inexperience, perceptions of risk, and a narrow focus on timber resources. These examples were implemented as part of large, codeveloped, management-inspired projects focused on climate change adaptation and threat reduction.

    ... One seminal article (Millar et al., 2007) provided a conceptual framework for adaptation that could be incorporated into forest conservation and management strategies. Millar et al. (2007) categorized adaptation approaches into resistance, resilience, and response (now often referred to as transition; Nagel et al., 2017). Generally, these represent increasing degrees of novelty, effort, and risk, as well as a lengthening of the temporal perspective for assessing success.... Indigenous people of North America likely promoted the expansion of mast and fruit species, such as the assisted movement of oak (Quercus L.), along the northern extent of its range (Abrams & Nowacki, 2008).

    ... The case studies presented are examples of successfully overcoming barriers of experience, risk, and practice employed within an ecosystem context to actualize FAM at operational scales.... We have outlined approaches to minimize risk of failure through an adaptation framework, which contain a range of adaptation strategies that incorporate FAM to varying degrees. These include (1) a resistance strategy, which largely defers consideration of regeneration and compositional shifts, including FAM, to a future date, (2) a resilience strategy, which may include an assisted population expansion, and (3) a transition strategy, which may incorporate multiple forms of FAM, including assisted range expansion and occasionally assisted species migration. Although the latter presents considerable challenges to conservation theory, value perceptions, and barriers under policy, we have shown its application under limited circumstances to be warranted.

    ... FAM of novel genotypes and species of trees is likely to be an important component of some adaptation strategies in order to sustain ecosystem functions including hydrology, tree productivity, carbon storage, and wildlife habitat. The pursuit of FAM is timely, especially as the risk to many forests increases or has already changed such that investments to maintain existing ecosystems may pose a higher risk than shifting to non-native or nonlocal species better adapted to emerging conditions. Employing FAM within an adaptation framework like the one presented here will improve knowledge transfer and reduce uncertainty for routine use.

  • 2022: Can Australia Save a Rare Reptile by Moving It to a Cooler Place?, Yan Zhuang, 12 December 2022, New York Times
    EXCERPTS: Standing knee-deep in a swamp, the researchers plucked three dozen tortoises one by one from cardboard boxes, lowering them into the water. Then they watched as some of Australia�s most critically endangered reptiles took off into the wetlands, bound for an audacious experiment in climate adaptation. The project, set in a national park in Western Australia, is the latest flash point in a knotty scientific debate. The western swamp tortoise's natural habitat in Australia is becoming increasingly unsuitable as temperatures rise and rainfall decreases. So conservationists are moving some of the animals 200 miles south, to a cooler place where they have never lived before. Experts say it could be the only way to ensure the tortoises� survival in the wild.
         It is believed to be to be the first time researchers have tried to relocate a vertebrate species to a new habitat because of climate change. Doing so is a huge gamble, though, and not just for the tortoises. Introducing species into a new landscape can have unpredictable and sometimes catastrophic consequences, and ecosystems are so complicated that no amount of research can predict the full effects.... As the rise in temperatures outpaces species' ability to adapt, a growing number are being pushed closer to extinction. Moving them to more hospitable terrain — known as assisted colonization or assisted migration — is one of a suite of new techniques, some on the outer edge of science, that could help save select endangered species. But the efforts have also fueled a debate about how, or even whether, humans should manipulate nature in a quest to protect it.
         To Nicola Mitchell, an associate professor of conservation physiology at the University of Western Australia and the project's lead scientist, the central question is: Do we let nature run its course and "let our species die because of climate change? Is that a natural ending? Or do we have an ethical responsibility to save these species?" ... Only one self-sustaining population exists in the wild, containing about 70 adult turtles. That population, on the outskirts of Perth, faces the dual threat of habitat loss from the city's growth and of climate change, which has shrunk the cool, wet periods the tortoises need to feed and breed, before they hibernate through the hot summer months. Surrounded by the city, the tortoise cannot move to a new habitat on its own. It lives for 100 years, so its life cycle is too long to be able to naturally evolve to adapt to the changing environment.
         Professor Mitchell began to look at assisted colonization to protect the species around 2008, she said, when debate about the approach took off in earnest as the effects of a warming climate became increasingly clear. Today, the scientific community seems little closer to reaching a consensus, though she hopes the tortoise trial will nudge the discussion. ... While Professor Schwartz, the University of California scientist, had some reservations about assisted colonization, he noted that it was the least invasive of a host of new technologies that are becoming available, including gene editing, to make animals more climate-proof....


  • Robin Wall Kimmerer speaking at "Right Here, Right Now Global Climate Summit", University of Colorado, December 2022 (posted on youtube January 2023). LINK goes directly to timecode 41:04:

        "Protection of culturally specific knowledge is really important. The sharing of that knowledge needs, of course, to be in the hands of our people and decision-makers. But I want to differentiate between culturally specific knowledge — which is and I think should be held very closely within communities — and the application of scientific principles that our people have derived and practiced since time immemorial that can guide climate responses.
         "I think about the cultural value of thinking that our actions are not only on behalf of human people, of course, but on behalf of our more-than-human relatives. An aspect of that, that we can share, to perhaps guide some climate-related solutions are things like assisted migration — what one of my really respected teachers, Henry Lickers, called, "Helping forests walk."
         It is our responsibility as human people who have been gifted by so much from the plants that we need to reciprocate with our gifts — particularly in this time when the climate is changing so fast that our plant relatives can't move on their own. So the kinds of things that I would advocate sharing with the climate science community are these strategies of things like assisted migration. That is, the way in which our people participated in carrying our plant relatives around, from place to place, to new habitats as the environment changed.
         "It's an exchange of gifts: our human gift of mobility and seed planting in return for the gifts of the plants. And those kinds of broad values coupled to action.
         "And so I think about something like assisted migration in the face of climate change as deeply guided by our values, and also really pragmatic. Those kinds of sharing from Indigenous science and wisdom seem to be the appropriate pathways for sharing, as opposed to what is often asked for, which is really culturally specific information, which belongs to our people.
         "And so I think we have, maybe, this mutual process of discernment of what are the things that we can share to guide climate adaptation on behalf of our own people as well as our relatives — as opposed to the culturally specific knowledge which is within communities."

    Editor's Note: Kimmerer first used the term "Helping Forests Walk" in 2009 while developing a new project idea in collaboration with the U.S. Forest Service. In 2011 the USFS awarded a grant of $45,000 to the Center for Native Peoples and the Environment (which is hosted in the SUNY College of Environmental Science and Forestry). This project is listed on Kimmerer's faculty page, and is archived on the chronological "Collaborative Projects" page of the center, where it reads:

    "Helping Forests Walk: Building resilience for climate change adaptation through forest stewardship in Haudenosaunee communities": The goal of this five-year project was to engage Haudenosaunee Nations in a process to assess opportunities for collaboration on issues of climate change mitigation and adaptation related to forest stewardship in tribal communities. The project draws upon traditional ecological knowledge and scientific ecological knowledge in identifying information needs in support of potential tribal responses to climate change, including engagement with policy development and capacity building for forest stewardship in a cultural context at the tribal, regional, national, and international levels. This project was conducted under the direction of PIs Dr. Marla Emery of the US Forest Service; Dr. Robin Wall Kimmerer; Henry Lickers, Scientific Chair, Haudenosaunee Environmental Task Force; David Arquette, Chair, Haudenosaunee Environmental Task Force.
    PRESS RELEASE: "Interior Department Takes Action to Strengthen Endangered Species Protections", by U.S. Department of the Interior, June 2023.
    EXCERPT: "... The Department of the Interior today announced significant action to better facilitate species recovery by providing more flexibility for the introduction of threatened and endangered species to suitable habitats outside their historical ranges.... The U.S. Fish and Wildlife Service has finalized revisions to section 10(j) regulations under the Endangered Species Act that will help improve the conservation and recovery of imperiled ESA-listed species in the coming decades, as growing impacts from climate change and invasive species cause habitats within species� historical ranges to shift or become unsuitable. The prior regulations restricted the reintroduction of experimental populations to only the species' historical range except under extreme conditions.... 'At the time the original 10(j) regulations were established, the potential impact of climate change on species and their habitats was not fully realized, yet in the decades since have become even more dramatic,' said Service Director Martha Williams. 'These revisions will help prevent extinctions and support the recovery of imperiled species by allowing the Service and our partners to implement proactive, conservation-based species introductions to reduce the impacts of climate change and other threats such as invasive species.'"
    "Assisted Migration Helps Animals Adapt to Climate Change", by Joanna Thompson, October 2023, Sierra Magazine
    EXCERPTS: "... In July, the US Fish and Wildlife Service changed its policy around the practice of 'assisted migration' — a controversial strategy that involves moving an endangered species to a new area (often outside of its historic range) when its native habitat becomes too hot, too dry, too salty, or otherwise unsuitable to live in. Specifically, FWS removed the so-called historic range clause in section 10 of the Endangered Species Act. The update effectively means that wildlife officials might be able to relocate the key deer and species like it to new, more suitable habitats. But doing so may prove physically and ethically tricky — and it may require us to rethink our current conservation paradigm.
        Assisted migration, also known as conservation introduction, managed relocation, and "helping forests walk," is contested in part because it goes against the ethos that most US conservation policy is rooted in. "Our laws are set up in a way that sort of assumes nature is static," said Alejandro Camacho, an environmental policy expert at the University of California, Irvine.
        "What we'll be increasingly seeing is the development of novel species assemblages and novel ecosystems," Christopher Swanston, a climate adviser at the US Forest Service, said. "Ones that we sometimes haven't imagined and certainly haven't seen."
        The breathtaking pace of our current climate catastrophe, however, means some species can't keep up on their own. 'You can't both keep things the way they used to be and not intervene in a world of climate change,' Camacho said. Trees like the endangered Florida torreya (Torreya taxifolia), for example, can't just uproot themselves and migrate to cooler climes — which is where assisted migration comes in. A small but dedicated group of volunteers has been planting seeds from this slow-growing southern conifer in western North Carolina and Georgia since 2008, taking pains to place them on private property to avoid breaking the law (technically, it is legal to plant non-native flora in one's own yard, so long as the species isn't considered invasive). So far, the trees seem to be thriving.
        But not every expert is ready to plunge headfirst into species relocation. 'It's too easy to go too hastily into some of these activities,' said Mark Schwartz, a conservation scientist at the University of California, Davis. In ecological circles, one of the main concerns around assisted migration is that a freshly relocated species might get out of control and become an invasive presence in its new habitat. While this risk is much lower for organisms and ecosystems that share a continent (as opposed to those brought over from across the ocean), it has happened in rare cases. For example, rusty crayfish (Faxonius rusticus), which are native to the Ohio River Basin, began pushing out native crustaceans in parts of Wisconsin and Minnesota after fishers started using them as live bait. The other big concern is that a transplanted species might fail to thrive in its new range. Certain organisms — so-called narrow endemics — only exist in highly specific locations, such as a single lake or valley. Sometimes, these species are even named after the places in which they're found — Florida's key deer is one such example...."
    "Climate change is hastening the demise of Pacific Northwest forests", by Nathan Gilles, 16 November 2023, Columbia Insight.
    EXCERPTS: Its foliage, normally soft and green, is tough and brown or missing altogether. Nonetheless, the tree's reddish bark, swooping branches and thick, conical base identify it as the Pacific Northwest's iconic western redcedar. Christine Buhl, a forest health specialist for the Oregon Department of Forestry, plunges a tool called an increment borer into the dead tree's trunk. Twisting the handle of the corkscrew-like borer, she extracts a long, thin sample of the tree's inner growth rings. The rings become thinner over time, indicating the tree's growth slowed before the tree finally died. It's a sign that this redcedar, like thousands of others in Oregon and Washington, died from drought. "That's why it's the canary," says Buhl. "Any tree that is less drought tolerant is going to be the canary in the coal mine. They're going to start bailing (out)."
        For thousands of years, people have used redcedar to make everything from canoes to clothing. Its many uses have earned the species endearing names, including the "Tree of Life." More recently, scientists have started calling this water-loving relative of coast redwoods and giant sequoias by a less flattering name: "the climate canary." Last year, Buhl and colleagues reported that redcedars were dying throughout the tree's growing range not because of a fungus or insect attack but due to the region's "climate change-induced drought."
        Redcedars aren't alone. In recent years, at least 15 native Pacific Northwest tree species have experienced growth declines and die-offs, 10 of which have been linked to drought and warming temperatures, according to recent studies and reports. Many researchers, Buhl included, are now arguing that these drought-driven growth declines and die-offs are the beginning of a much larger and long-predicted shift in tree growing ranges associated with climate change.... For decades, scientists have argued that as atmospheric warming continues, growing ranges in the Northern Hemisphere will shift upslope in elevation and farther north, leaving many plants stranded in a warmer, drier world. The result is expected to be especially devastating for long-lived trees.
        ... But whereas redcedar is believed to be dying from drought alone, the Firmageddon and Douglas fir die-offs have been linked to a combination of drought weakening trees and insect pests moving in for the kill. "These insects are not normally tree killers," said [Daniel] DePinte. "This is evidence that the forests are reacting to climate change and droughts." ... Trees now common in California are predicted to migrate northward into Oregon and Washington. DePinte said the Douglas fir die-off in the Klamath Mountains might be the start of a larger ecological change that could see Douglas fir replaced in many areas by more drought-tolerant pines and oaks. "It's going to turn into more of a woodland over the long term," said DePinte. David Lytle, U.S. Forest Service deputy chief for research and development, said this kind of ecosystem change, called "type conversion," has already been observed elsewhere in the country, including the Southwest....
    "What is 'assisted migration' and what are the risks?", by Nathan Gilles, 28 December 2023, Columbia Insight.
    EXCERPTS: East of Seattle, on the banks of Snoqualmie River, row upon row of one- to three-foot tall tree seedlings sit snug in plastic cages intended to protect this experiment in adapting to climate change from the hungry mouths of deer. The young trees are located at the Oxbow Farm and Conservation Center, in Carnation, Wash. Once covered in invasive species, the Oxbow site has been ecologically restored using Pacific Northwest native plants, including eight tree species. But while all the trees at the site are native to the region, some started their lives as seeds hundreds of miles away. Shiny metal tags mark the trees' natal homes. One reads "Coos," short for Coos Bay, Ore., over 400 miles to the south. Another tag indicates a seed source in Oregon's Willamette Valley south of Portland. Both trees are native big leaf maples, trees that have been dying in large numbers throughout western Washington due in part to abnormally warm summer temperatures.
        This is the problem Matt Distler, Oxbow's conservation program manager, hopes to solve: how to use assisted migration to keep Pacific Northwest native trees on the landscape as climate change kills them off. ... "I think people are interested in this idea [assisted migration] because it is hopeful," says Distler. "Meaning there are [climate] adaptation strategies that hold some hope in what seems like a grim reality." Because the current climate of Coos Bay and the Willamette Valley look similar to Oxbow's predicted future climate, the maples grown from seed found in these southern locations should be better adapted to climate change. In the coming years and decades, Distler hopes to test this idea, not only for big leaf maple, but also western redcedar, another native species that's imperiled by warmer, drier summers.
        Distler is a cautious practitioner of assisted migration rather than an evangelist. He's part of a growing number of practitioners concerned that many assisted migration efforts in the Pacific Northwest have lacked both scientific rigor and consent from local communities. "Assisted migration is definitely a hopeful tactic," says Distler. But, he says, to be done right, it needs to be "carefully considered, well-monitored and collaborative." These rules and this public discussion, Distler and others claim, are needed because assisted migration is gaining in popularity and decisions about what gets planted today could have lasting ecological effects for decades to come.
        In the Pacific Northwest, organizations from the U.S. Forest Service to the cities of Portland and Seattle and even a citizen-led effort are now practicing assisted migration as a way to help forests and prevent species extinction in the face of climate change. But what's emerged from these efforts is an ongoing debate about what type of assisted migration the region needs. A clear divide has developed between organizations like Distler's, which are advocating for a type of assisted migration that would help the region's struggling native trees, and one that could instead see native trees replaced on the landscape by trees from the south, many of which are also threatened by climate change, including coast redwoods and giant sequoias.
        The debate centers around two forms of assisted migration: assisted population migration and assisted species migration.... Assisted population migration, also called "assisted gene flow," involves moving a species' seeds — and by extension its genes — within its current growing range. Typically, this means moving seed sources from drier, warmer regions in the south to cooler, wetter ones in the north, like Distler is doing at Oxbow with big leaf maple.... There's also a third form of assisted migration, called "range expansion." which involves moving a species just beyond its current growing range. All three forms of assisted migration are based on the now well-tested idea that trees and other plants have growing ranges that are largely determined by climate factors, including temperature and precipitation. These factors limit how far north and south, west and east, and up and down in elevation a plant can grow.
        ... It's been estimated that trees would need to migrate at about 10 times their natural rate to keep up with climate change. This is where assisted migration comes in. Assisted migration is the deceptively simple idea that humans can help trees and other plants — and even climatically displaced animals — keep up with climate change. The problem, says [Michael] Case, is plants and their ecosystems aren't simple. "Whenever you plant something in an area where it's not locally found you increase the risk of failure [of the species]," says Case. "You also increase the risk of disturbing ecosystem functions and processes." Case says the Nature Conservancy is focusing on population migration but isn't considering species migration because native trees are more likely to survive if moved within their growing ranges and are highly unlikely to disrupt local ecosystems. This is also Distler's position. "When you are talking about moving populations of a native plant this is something to be done with care, this is not a dramatic act," says Distler. "But move a species far north of its native range, and there are more potentials for risk."
        The U.S. Forest Service has taken a similar position and is practicing only population migration, according to Dr. David Lytle, deputy chief of research and development for the agency. Lytle oversees research efforts for the agency nationally. "The Forest Service certainly engages in the first [population migration] and we would carefully consider range expansion, but we are very, very cautious and do not engage in the long distance movement and establishment of plant material outside and disjunct from the historic range of a species," says Lytle.... "You move a species outside its native range and you remove all the factors that it has evolved with and that control it — competition, diseases, insects," says Lytle.
        The USFS's largest assisted migration effort in the Pacific Northwest is called the Experimental Network for Assisted Migration and Establishment Silviculture or ENAMES project, an effort spanning Forest Service operational and research offices in Washington, Oregon and California. ENAMES currently has eight sites where migrated trees have been planted, with 29 more sites in the works. ENAMES involves population migration for native Douglas fir and ponderosa pine. While the USFS has experimented with assisted migration on a smaller scale for decades, ENAMES takes the next step. The project is an attempt to apply population migration on a large scale in part as a way to replant regional forests following wildfires and other climate disruptions.
        Not everyone is critical of species migration, especially not for two popular California trees that are already common in Oregon and Washington cities and yards: coast redwoods and giant sequoias. Probably the most well-known organization advocating for species migration is the Seattle-based, citizen-led PropagationNation. Philip Stielstra, a retired Boeing employee and PropagationNation's founder and president, declined to comment for this story. Arguing that redwoods "belong here in the PNW" and are better at storing carbon than Pacific Northwest native trees, PropagationNation has planted coast redwoods and giant sequoias in several Seattle-area parks. The group has also planted redwoods at an ecological restoration site in the Olympia area.... Both Archangel's and PropagationNation's efforts raise the possibility that Pacific Northwest native plants could be displaced by redwoods.... [David] Milarch also says his redwoods and sequoias are unlikely to replace native plants in local ecosystems because most of them are being planted inside urban areas, which are already largely unnatural spaces filled with nonnative species.
        Michael Yadrick, plant ecologist at the City of Seattle Parks and Recreation, who is also a member of the Forest Action Network, says his department is currently practicing population migration for six native species, including Douglas fir and western redcedar. Yadrick says his department isn't considering planting redwoods or sequoias as part of its assisted migration efforts. "I think there is a concern with incorporating species that in the near history weren't found here although they could have been here in deep time," says Yadrick.
        Forest Ecologist Rolf Gersonde oversees assisted migration efforts for Seattle Public Utilities. He's also a member of the Forest Action Network. Gersonde also says his department isn't considering assisted migration for redwoods or sequoias, in part because it's unclear how well-adapted the trees are to the region. According to Gersonde, a better candidate for long-distance migration is incense cedar.
        Incense cedar's range is believed to extend through California and Oregon, ending near the Washington border south of Portland. (Though the popular guidebook Trees and Shrubs of the Pacific Northwest claims the species has a disjunct population in Washington state north of the Portland metro area.) Incense cedar has been planted extensively along Interstate 5 in both the Portland and Seattle areas. Gersonde helped design Seattle's Stossel Creek assisted migration project, which includes a small experimental plot of incense cedar. The rest of the project involves population migration. Incense cedar is often discussed as "surrogate" or replacement for western redcedar, though Gersonde says this wasn't the intention behind including the tree at Stossel Creek. "We are using [incense cedar] because it overlaps with [the range of] western redcedar in southern Oregon. But incense cedar is much better adapted to warmer drier conditions," says Gersonde "We want to increase the genetic diversity of our local [forest] communities. Not replace it, but add to it."
        ... Portland Parks and Recreation's Urban Forestry program is experimenting with moving 11 tree species, according to department spokesperson Mark Ross. Several of these species have growing ranges that extend through California and end in southern Oregon, including coast redwood, California black oak and canyon live oak. Also on Portland's list are Interior live oak and MacNab cypress or Shasta cypress. The ranges of both species are currently confined to California.
        ... Distler says one of the messages that needs to be conveyed to the public is that assisted migration in all its forms isn't a technological fix or solution to climate change. Assisted migration, like tree planting generally, doesn't lower the amount of greenhouse gases being emitted. What assisted migration is, says Distler, is a way to adapt to climate change that is already happening. "I think there is a moral hazard in focusing too much on assisted migration because it can take energy and attention away from cutting emissions," says Distler.

    NOTE: THE ASSOCIATED PRESS (Portland OR office) published a much shorter version of this lengthy piece by Nathan Gilles, and added some additional text and comments. Many media outlets posted this A.P. version of the story.

    "Can We Save the Redwoods by Helping Them Move?", by Moises Velasquez-Manoff, October 2023, New York Times Magazine. Note: This is a long-form essay.

      EXCERPTS: ... This problem — a species under increasing threat in the place it has long inhabited — isn't limited to giant sequoias. According to the International Union for Conservation of Nature, more than 12,000 species are in similar situations. The question is what, if anything, can be done to prevent a raft of extinctions driven by our remaking of the earth's climate. For David Milarch, the answer was clear. He ascribed to something called "assisted migration": moving species to more hospitable areas. Of course, you can't move a massive, 200-foot tree itself, so Milarch learned to grow new trees from samples he had collected in order to plant these genetic copies beyond the tree's current range. Philip Stielstra was taken with this idea (though he would later be unable to find any scientists who agreed with Milarch's claim that the genetics of specific "champion" trees were special). Not only would the species be more likely to survive, he thought, but because the trees suck so much carbon out of the atmosphere, they could also help fight climate change. By the end of the trip, Stielstra resolved to move some of Milarch's trees to Seattle.

    ... Stielstra knew that Milarch would send him coast redwoods, a close relative of the giant sequoia (both species are commonly referred to as "redwoods"). And he knew they could survive Seattle's climate: Three giant sequoias, about 80 feet tall, were growing by the entrance to a freeway that passed through his neighborhood, and there were groves of both coast redwoods and giant sequoias, healthy and majestic, in the Washington Park Arboretum that were planted decades earlier.
        Not wanting to cause ecological problems by planting the trees across the Pacific Northwest, Stielstra would eventually contact one of the foremost experts on the coast redwood, a botanist and forest ecologist named Stephen Sillett, at Cal Poly Humboldt, and ask if moving redwoods north was safe. Sillett thought planting redwoods around Seattle was a fantastic idea. ("It's not like it's going to escape and become a nuisance species," Sillett told me, before adding, "it just has so many benefits.") Another factor encouraged Stielstra too: Millions of years ago, redwoods — or their close relatives — grew across the Pacific Northwest. By moving them, Stielstra reasoned, he was helping the magnificent trees regain lost territory.
        Assisted migration hinges on a deceptively simple-seeming notion: that we can, and should, help solve a problem of our own making; that we should save at-risk plants and animals by moving them to safer places. The concept was first floated in the 1980s, when some conservationists foresaw that as climate shifted, certain species protected by wildlife preserves might not be able to survive over the long-term within their boundaries. Yet the practice didn't really become a topic of scientific debate until two decades later, when a group of self-described citizen scientists decided, like Stielstra and Milarch, to do something to prevent a tree from disappearing from its current range.
        Torreya taxifolia is a conifer that grows only in the ravines of the Apalachicola River system, in the Florida Panhandle. The tree, also known as the 'stinking cedar,' has been harmed by fungal disease since at least the 1960s. The Torreya Guardians, as the group called itself, cited evidence that the tree had been pushed to its current southerly location by the glaciers of the last ice age but was in fact better adapted to more temperate conditions than those of northern Florida. It was unable to migrate back northward as the glaciers receded, in part, they argued, because a species of giant tortoise that may have helped disperse its seeds had gone extinct. The Guardians didn't go through an official review process to validate their contentions. They considered the tree's circumstances so dire, and officials so slow to act, that beginning in the mid-2000s, they started moving the tree on their own, planting seeds and young specimens on private lands in North Carolina, Ohio and elsewhere. Their aggressive approach to conservation featured prominently in numerous scientific articles that followed, discussing the pros and cons of assisted migration."
        ... For trees, the conversation has shifted from "should we do it?" to "how can we do it best?" The U.S. Forest Service, among other agencies, has experiments underway around the country to study what trees will grow most vigorously in today's rapidly shifting climate. Some of these trees are southern varieties of species that already grow in an area. But in a few other plots, the Forest Service has planted species, like the relatively drought-tolerant ponderosa pine, that don't yet inhabit that region of the country. By moving these trees into the area, the agency is essentially testing which, if any, of today's nonnative trees have the best chance of thriving there in the future.
        Critics argue that 'nature' should be left to produce its own adaptations. The counterargument is that humanity's global impact has become so all-encompassing that 'nature,' in the sense of untouched wilderness, no longer exists (if it ever did) and that inaction could mean the disappearance of life-forms or the collapse of ecosystems. Jessica Hellmann, executive director of the University of Minnesota's Institute on the Environment and an early thought leader on what she prefers to call "managed relocation," likens the practice to chemotherapy. "You don't say, 'Oh, is chemotherapy a good idea?' No, it's a terrible idea," she says. "It's only a good idea if you're confronted with some other terrible thing," like cancer. Similarly, she says, assisted migration is appropriate when contrasted with the other possibility: extinction if no one intervenes....
    "Desired REgeneration through Assisted Migration (DREAM): Implementing a research framework for climate-adaptive silviculture", by Alejandro A. Royo, October 2023, Forest Ecology and Management.
    ABSTRACT EXCERPT: Global change is reshaping climatic conditions at a tempo that exceeds natural migration rates for most tree species. As climate change amplifies the disparity between species� adaptive capacity and local climates, tree populations risk becoming geographically stranded in increasingly unsuitable conditions. This mismatch may cause catastrophic losses of key forest ecosystem services such as carbon sequestration, habitat provisioning, and forest products. In response, forest managers and researchers are developing a suite of climate-adaptive strategies designed to sustain forest diversity and function. Among these, forest assisted migration (FAM) involves the movement of planting stock from source populations to locations either within or beyond their current ranges. The goal is to establish forests that can survive in today's climate and expected to thrive in future conditions, thereby sustaining ecosystem good and services. Because FAM is still in its infancy, implementation is limited by many uncertainties. Climatically derived seed sourcing is needed to ensure that planting stock possesses the ecophysiological amplitude to withstand both current and future climatic conditions at the destination site. Additionally, more knowledge about the impacts of local herbivores and intraspecific competition are needed because these drivers will co-regulate seedling success along with climate. Practically, these uncertainties must be addressed to instill in managers sufficient confidence that FAM investments will fulfill long-term management and societal goals relative to other silvicultural approaches.


    Do redwood trees have a place in the future of WA's forests? They're already here - by Amana Zhou, 21 January 2024, Seattle Times

    EXCERPTS: The acre of coast redwood trees here was planted over three decades ago and has grown roughly twice as fast as its 130-year-old native neighbors of Douglas fir, hemlock, and cedar trees. At 130 feet, the redwoods are on pace, maybe in another 30 years, to overtake the rest. Their species is named Sequoia sempervirens, meaning always living, for good reason. They are among the oldest trees on Earth. Their thick, reddish-brown bark is resistant to fire, rot and insects, allowing water to be sent up their massive trunks for centuries. Unlike most other conifers, if you cut one down, new growths will sprout in a tangled knot, each branch wandering to become a leader.
         ... If you know where to look, redwoods can be found across Washington and Oregon. In Seattle, coast redwoods and giant sequoias — another species commonly called redwoods — can be found facing Husky Stadium, in Laurelhurst Park, in the Washington Park Arboretum and even in the front lawn of a West Seattle home. Some tree farmers on small areas of land have also started growing redwoods for commercial logging.
         ... Philip Stielstra, a 77-year-old former Boeing consultant, has visited the stand of redwoods on Hood Canal many times with Dave Robbins, the former manager of the Hama Hama Co., who planted the trees as a sort of experiment. Stielstra's organization, PropagationNation, is dedicated to a mission of "painting the Pacific Northwest redwood."
         As climate change threatens Washington and Oregon's forests with wildfire, drought and disease, Stielstra sees coast redwoods — with their immortal qualities and fast ability to soak up carbon — playing a key role in the future of the Northwest's forests, from industrial tree plantations to city parks to restored habitat. At least 15 native Pacific Northwest tree species — including the Western red cedar — have experienced growth declines and die-offs in recent years, according to nonprofit news outlet Columbia Insight. Many of these effects have been linked to drought and rising temperatures.
         Since 2016, PropagationNation has sold or given away nearly 10,000 coast redwoods or giant sequoias to city parks, conservation districts, tribes and private citizens in Washington. Driving between Tacoma and Olympia on Interstate 5, Stielstra can point out the shape of giant sequoias, "upside down ice cream cones." Name a city around Puget Sound and chances are Stielstra has helped plant one there.
         "We are just trying to be a spearhead of saying, 'We're going to do this whether we have approval from any appointed body or not,'" he said.
         Washington plants, grows, and chops down forests to generate revenue. State Department of Natural Resources forest geneticist Jeff DeBell said the agency's preference is to keep planting the trees other plants and animals are already used to.
         This planting season, PropagationNation has scaled up and aims to sell 12,500 seedlings — though Stielstra's goal is for nothing short of a movement. He eventually wants a million redwoods planted a year across the Pacific Northwest, ideally by government agencies and timber companies alike. More than 90 million trees are planted in Washington and Oregon each year, according to industry estimates. Stielstra asks, why can't 1% of those be redwoods?
         Determining whether redwoods are native to the Pacific Northwest is a matter of time scale. Since European settlers arrived in North America, coast redwoods have been primarily found between southwest Oregon and central California, and giant sequoias, which grow better in drier, sunnier places, were found inland along the western slope of the Sierra Nevada. However, it's likely the plant's ancestral range before the last ice age was far broader, said Russell Kramer, an ecologist who has been hired by PropagationNation to write educational materials in the past. The fossil record shows signs of a redwood relative and the dawn redwood, a related species now mainly found in China, across the Intermountain West, specifically in Montana and Idaho, he said. Though, to Kramer, the redwood's fossil record is somewhat irrelevant to questions around whether the plant can and should grow in Washington and also ignores the fact that humans have long been moving and transporting animals and plants to non-native environments, leading to both nuisance invasive species and agricultural successes.
         Nearly all the tree species of the Pacific Northwest are found growing alongside coast redwoods and giant sequoias, he said. Adding another species like the coast redwood with its decay-, fire- and disease-resistant properties would mean giving mixed-species forests another line of defense, Kramer said. DeBell, the DNR forest geneticist, said while the agency is aware redwoods can grow successfully in the state, its preference is to stick to Douglas fir, which dominates the timber industry in the Pacific Northwest. The agency manages over 2 million acres of forests and plants between 5 million and 7 million trees a year. ... DeBell said that he was unsure the coast redwoods — which come from a cool, moist and foggy part of California — would be the immediate choice for Washington's forest resiliency as the state warms up, as opposed to trees already adapted to drier conditions like the ponderosa pine, a Douglas fir accustomed to growing in a warmer climate, or even the giant sequoia. "I don't have data to tell you how it's going to work out, but I'm not sure that's the intuitive choice," he said.
         ... Traditionally, tree farmers choose Douglas fir seeds from a nearby source, DeBell said. But anticipating a hotter drier future, planters are starting to source seeds from farther south, he said. Just how much Washington's climate will change, and how far south seeds should be harvested, is unclear. To shed light on that uncertainty, the U.S. Forest Service, DNR and other state agencies are growing Douglas fir on 18 West Coast sites. Each contains seeds sourced from 23 different environments across the three states. ... Greg Ettl is also studying how well redwood seedlings do in drought and under frost — both conditions that would be new for trees from the California coast. He is also looking to survey the coast redwoods and Douglas firs growing alongside each other across the state to compare their growth rates under different conditions and soil types. Coast redwoods are a promising tree, not only for their commercial appeal and speedy growth, he said. The species is shade tolerant, meaning tree farmers could continually grow younger stands beneath older ones while harvesting every few years or so. Tree farmers would also not have to replant after cutting one down since the species can resprout from its stump, he said. In comparison, Douglas fir are less tolerant of shady conditions. In recent years, farmers have also seen more Douglas fir seedlings fail on well-drained and sunny slopes, Ettl said.
         To tree farmer Terry Lamers, the coast redwood with its beautiful "straight as an arrow" form and small limbs is nothing short of an arboreal cash cow. In his family-owned tree farm of just under 500 acres southwest of Salem, Ore., redwoods, which fetch a higher price than Douglas fir, have been the only species he has been planting for the last 10 years. His tests started the way they do for many family tree farmers, including Robbins: by planting several species on his property decades ago. "Redwood is doing extremely well on every site that we've planted it," he said. "North slopes, south slopes, east slopes, west slopes, the worst soil we've got, the best soil we've got. It has excelled everywhere." In Lamers' experience, coast redwoods grow twice as fast as Douglas fir and surplus redwood seedlings have been easy to sell.
         ... At the Jamestown S'Klallam tribe on the Olympic Peninsula, Hilton Turnbull, the tribe's habitat biologist, is planting redwoods alongside species like Douglas fir, western hemlock and grand fir. The tribe is restoring a part of the Dungeness River's flood plain and creating more habitat for endangered salmon. Turnbull and other crew members have planted about 1% or 2% of the trees as coast redwoods and giant sequoia. He's hopeful they can grow more quickly into the large trees needed to create log jams in the river, slowing down water for the spawning salmon.... "Climate change has kind of forced our hand," he said.... "Incorporating redwoods and sequoias is just a part of our strategy."
    "Arriving at a tipping point for worldwide forest decline due to accelerating climatic change" - by Cuauhtemoc Saenz-Romero, 13 February 2024, Forestry Chronicle
    ABSTRACT: The 2023-2024 El Ninõ is inducing an acceleration of global warming that is likely to far exceed 1.5C. The Boreal summer of 2023 provided numerous examples of catastrophic forest fires (e.g., >18 million hectares of forest burned in Canada, making the Canadian forest a clear carbon source rather than a carbon sink), a trend that has been accompanied by worldwide examples of unusual tree mortality linked to hotter droughts. It is reasonable to expect that the warming induced by El Ninõ could push forests in several parts of the world over a tipping point, where they will hardly be able to recover their original state. It is therefore necessary to address the meaning, realistically, of sustainable forest management in the era of accelerated climatic change. The ultimate goal of the broadly accepted silvicultural practice of maintaining forests in a state that resembles what we recognize as temperate or boreal forests is becoming more of an idealistic dream rather than an attainable goal. Thus, the time has arrived to discuss painful forest management decisions, such as anticipated thinning to reduce water competition and the gradual replacement of native local forest populations with more drought-resistant provenances and species.
    "How assisted migration could help species survive climate change" - by Sueellen Campbell, 12 March 2024, Yale Climate Connections Note: This is a good short article linking to recent news items on this topic.

    Moving trees north to save the forests - by John H. Tibbetts, 6 March 2024, Knowable Magazine

    TAGLINE: As the world warms, trees in forests such as those in Minnesota will no longer be adapted to their local climates. That's where assisted migration comes in.
        EXCERPTS: ... Brian Palik, a forest ecologist with the US Department of Agriculture's Forest Service Northern Research Station, stops and points to a newcomer under the red-pine canopy: a broadleaf deciduous tree, bitternut hickory, as high as an elephant's eye at about 10 feet tall and eight years old. "It's doing really well," he says. This bitternut hickory probably shouldn't be thriving in the Cutfoot Experimental Forest in north-central Minnesota, near Grand Rapids. It likely began as a seedling in a nursery in Illinois, to the south, where deep freezes are less extreme. Normally, if a southern-adapted seedling is planted in an unsuitably cold climate like this one, it can risk frost damage and its survival is threatened. But the newcomer's lush, green foliage exudes good health. It is a promising sign in a project that aims to keep forests growing in a warming world.
         In the Cutfoot Experimental Forest in 2016, the Forest Service planted seedlings of eight tree species from seeds, collected from woods up to several hundred miles farther south, as part of an experiment that Palik manages. Four species are native to this northern region: eastern white pine, northern red oak, bur oak and red maple. Four species are uncommon or nonnative: white oak, bitternut hickory, black cherry and ponderosa pine. Two decades back, these southern seedlings likely would have struggled to flourish here. Today, Palik and his team can see the success of almost all the southern trees they planted. "They are going like gangbusters," he says, "which is indicative that the climate is right for them," although the researchers don't know about the seedlings' long-term health yet. In seven of the eight species, the survival rate has been 85 to 90 percent. "The climate typical of southern Minnesota from 20 years ago is now in northern Minnesota," Palik says. Climatic conditions have moved about 200 miles north in just two decades.
         Palik's project is an experiment in forest assisted migration, the relocation of trees to help woodlands adapt and flourish despite the heating of their habitats from climate change. Foresters advocating assisted migration are typically not aiming to save specific species — instead, by moving trees, they want to help sustain productive forests for multiple benefits such as carbon storage, water filtration, wildlife habitat, recreational beauty and timber. Experimenting with assisted migration calls for a different way of thinking about nature. Whereas ecological restoration typically looks to the past for cues on repairing degraded places, foresters exploring assisted migration are planting warmer-climate trees that could have a better chance of thriving under warmer future conditions.
         ... Assisted migration research for conservation is getting bolder with growing concerns about future forest disruption from climate change. And the movement is growing internationally, with research happening in Spain, Canada and Mexico. Today, Palik's study is one of 14 research projects in a network named Adaptive Silviculture for Climate Change (ASCC). Most foresters who are experimenting with assisted migration are planting trees farther north or planting trees from lower elevations at higher elevations. Sites across North America include western larch-mixed-conifer forests in the Flathead National Forest in Montana; diverse pine-hardwood woodlands at the Jones Center at Ichauway in Georgia; spruce-fir forests of the Colorado State Forest; and mixed-pine-hardwood forests of the Petawawa Research Forest in Ontario, Canada. Some Forest Service scientists, including Palik, expect that assisted migration will transition from a subject of research to a standard management strategy.
         ... Palik took ponderosa pine seedlings from seeds collected in northwest Nebraska, hundreds of miles to the south and west, and planted them in experimental plots for research purposes. Though only a fifth of them lived, the ones that survived have flourished. His experiment suggests that ponderosa pine — a tall, long-needled tree used for timber but adapted to warmer, dryer summers and more moderate winters — could someday thrive in northern Minnesota if red pine falls away.... It's imperative, Palik says, that we work to maintain useful woodlands. "The forests at the end of the century are not going to be your grandfather's forests," he says. "But they're going to be the forest your grandchildren inherit."
    "Can Redwoods and Sequoias Produce Offspring in the Pacific Northwest?" - by Nathan Gilles, 21 March 2024, Columbia Insight
    EXCERPTS: In October of last year, The New York Times ran a story asking, "Can We Save the Redwoods by Helping Them Move?" The story centered on Washington state resident and redwood enthusiast Philip Stielstra. A retired former Boeing employee, Stielstra is the president of PropagationNation, a nonprofit working on migrating coast redwoods and giant sequoias to the region, partly to help preserve the species for future generations. This strategy, called "assisted migration," follows the idea that people can, and some argue should, help species migrate to help prevent climate change-induced extinction. The goal of assisted migration varies from using migrated trees for timber to preserving plant genes to creating self-sustaining populations of trees that have "naturalized" or established in their new environment.
         While the Times story was largely sympathetic of Stielstra, PropagationNation and similar organizations, it nonetheless ended on what for me was something of an ecological cliffhanger: Once planted here, do the trees go on to reproduce, creating self-sustaining forests?
         ... According to my own investigation, the answer to the question do redwoods and sequoias recruit in the Pacific Northwest? is probably no for giant sequoias and maybe but not often, for coast redwoods. If it is true that the two tree species are not recruiting — or not recruiting well — outside their native ranges, this suggests, say experts I spoke with, that the trees might not naturalize in their new homes. This further suggests that efforts to migrate the trees to the region might require ongoing human management to be successful, begging the question, is this what successful assisted migration should look like?
         ... "I don't think we see ourselves as the saviors of the redwoods [and sequoias] in the sense of saving them from extinction," says Stielstra. "We just think that with our ecology and climate, they [redwoods and sequoias] can do really well here, so we're just trying to help advance that cause."
         ... Although redwoods and sequoias have been planted in the Pacific Northwest for decades and can easily be found growing and even thriving in yards, parks and arboretums in Washington and Oregon, these are trees that were grown under controlled nursery conditions and then planted. What is far more difficult to find, say experts, are examples of the two species growing in the region without human aid. In fact, many suspect that coast redwoods and giant sequoias are struggling to reproduce outside their native range because the environmental requirements for saplings and adult trees is different from what seeds need to germinate and seedlings need to grow. But the exact reason is still something of a scientific mystery. Despite being two of the most iconic tree species in the world, there really isn�t a whole lot of information on how best to migrate them.
         ... Coast redwoods are native to the temperate foggy coasts of northern California and southern Oregon. Giant sequoias are native to the western flank of California's Sierra Nevada known for both snow and frequent fire.
         GIANT SEQUOIA: ... In a phone interview, [Nate Stephenson] said he didn't know if sequoias were recruiting in the Pacific Northwest — or anywhere outside their native range — but said that if it's not happening, a lack of fire could be a factor.... "If the fire regime [in the Pacific Northwest] starts to turn into something more like what you get in the southern Sierra Nevada's of California, you might get more [sequoia] regeneration," says Stephenson.
         ... Asked if he thought more destructive fires might cause sequoias to go extinct, Stephenson said the tree's popularity makes extinction unlikely. "I'm not too worried about them going extinct. What does concern people is that we could lose the big old ones [in the Sierras]," says Stephenson.
         Although the sequoia's native range is limited to just 70 California groves covering a measly 44 square miles, the tree has been planted on nearly every continent on Earth, including the United Kingdom, according to a recent study published by Royal Society Open Science. A BBC story covering the study ends by noting that "while the trees are doing well in the UK, there's little chance of them taking over our native forests any time soon — they're not reproducing here as they need very specific conditions to take seed [germinate]."
         COAST REDWOOD: ... During my reporting, I heard a handful of rumors about the trees naturally producing seedlings outside their native range but was able to confirm just two possible cases. Both are at Portland's Hoyt Arboretum. According to arboretum curator Martin Nicholson, the young trees "appear to have grown from seed and are not root suckers."
         ... Whether self-cloning could play a role in redwoods naturalizing themselves in the Pacific Northwest is something of an open question. But Greg Ettl, associate professor at the University of Washington's School of Environmental and Forest Sciences, thinks it might. "In general, I think naturalization of [coast] redwoods [in the Pacific Northwest] should be possible, but much of this would come from clonal spread," Ettl wrote in an email. He went on to say, "It is likely that reproduction from seed is rare [in the Pacific Northwest] due to limited seed production, viability, small size and (maybe more importantly) lack of suitable sites." Ettl is currently testing the suitability of growing coast redwoods in the Pacific Northwest, including the species' drought and frost tolerance. He's one of the first researchers to do this.
         Another reason we don't see more redwood seedlings in the Pacific Northwest might have to do with climate, according to a study by Richard Winder, a retired research scientist at the Pacific Forestry Centre in Victoria, B.C.... To figure this out, Winder and colleagues germinated redwood seeds in greenhouses heated to mimic the springtime temperatures of the tree's native range. They also germinated seeds in the cooler springtime temperatures currently found on Vancouver Island. The number of germinated seeds under Vancouver Island temperatures was "tiny" compared to seedlings grown under warmer conditions, leading Winder to conclude that natural seedling recruitment isn't currently optimal there to "sustain ongoing populations." "You would want it to be warmer [on Vancouver Island] than it currently is in order to foster recruitment," Winder told me over Zoom. In other words, the further north you move the tree outside its native range, the less likely recruitment will become because temperatures will simply be too cold. Winder's findings do suggest that recruitment on Vancouver Island will likely increase as temperatures rise under future climate change. But there's a big caveat to that: fog.
         Redwood recruitment is believed to benefit from the fog that blows in from the Pacific Ocean. This fog keeps the seedlings from drying out while their young roots burrow down in the forest duff in search of water in the soil. Whether the future has enough fog when redwood seedlings need it, says Winder, is uncertain. In the meantime, I plan to keep looking under mother trees for those rare recruits.

  • A climate analog approach to evaluate seed transfer and vegetation transitions - by Bryce A. Richardson, Gerald E. Rehfeldt, Cuauhtemoc Saenz-Romero, and Elizabeth R. Milano, 2 April 2024, Frontiers in Forests and Global Change
    EXCERPTS: Because plants can be adapted to seasonal temperature, precipitation, and their interactions (e.g., Putz et al., 2021; Richardson et al., 2021), defining seed transfer limits with a few climate variables can lead to an overestimation of seed transfer limits. More precision in defining climate is needed when considering wide-ranging species and assisted migration due to climate change. We offer an approach for calculating climate distances to identify future climate analogs — sites with contemporary climate similar to the future climate at a target location. Analogs are drawn from biome and plant inventory databases which provide projections of potential future vegetation for developing strategic seed transfer and proactive restoration plans. The approach is species-independent, operating entirely in climate space, incorporating 19 climate variables, and projections for three Representative Concentration Pathways (RCPs) from three general circulation models (GCMs) for future mid-century climates (IPCC, 2014). We take into consideration a large amount of variation that accompanies future climate projections and simplify the decision process by averaging large climate variability into a single criterion to determine climate analogs.
         As such, the approach has broad applicability, from land use management to municipal planning. Thus, we hope that our work might contribute to fill an information gap between complex research papers showing the large extent of diverse combinations of GCMs, scenarios of accumulated greenhouse gas emissions and projected climate futures, and on the opposite spectrum, an urgent need for tools to guide practical forest management decisions by foresters and conservationist practitioners. The need to move on from the academic rumination to specific forest management decisions to face climatic change impacts, is becoming more urgent, due to the current acceleration of climatic change (Hansen et al., 2023; Saenz-Romero, 2023).... Therefore, to provide context to Euclidean climate distances, we use elevation to link climate distances, temperature, and genecology. We argue that climate distance thresholds can be defined from the relationship between climate distances and elevation, that is, their equivalence.

        Yellow diamond is the target site.
        Red = strongest match; Purple = moderate; Black = weak
        Map is sourced from the Supplementary Material.

      Our goals are to: (1) present and illustrate a climate distance approach to locating reference period climates (1961-1990) that are climate analogs to projected mid-century climates (decade centered in 2060: 2056-2065) for target locations, (2) define climate analog thresholds by relating climate distances to elevation differences along altitudinal clines at a random selection of geographic points, and (3) infer vegetative changes to plant communities, potential impacts to conservation, and the climatic factors affecting these changes using target locations examples from a wide array of contrasting North American ecosystems.... Predicted climate distances at 200 m and 300 m established the upper thresholds for strong and weak analogs, respectively.

    DISCUSSION: We present a climate distance + nearest neighbor approach to locating mid-century climate analogs by searching biome and species inventory databases containing climate estimates for point locations. The approach is independent of species genetic information. Populations of all species occurring at the analog site should be suited to the mid-century climate of the target location. This species independence is a distinguishing feature of our approach from trait-based seed transfer approaches (e.g., Rehfeldt et al., 2014; Richardson and Chaney, 2018) and carries advantages and disadvantages for developing seed transfer guidance. The advantage is that the approach can be applied without genetic information, which would benefit many research limited plant species, especially in regions or countries with high biodiversity. The disadvantage is that this approach can potentially be excessively specific to generalists, species that have broad adaptive clines [e.g., Pinus monticola (Richardson et al., 2009) and Thuja plicata (Rehfeldt et al., 2020)]. For instance, the analogs found for an Ontario, Canada location (Supplementary Figure S4) are closely consistent with results of niche models coupled with genecology estimates made for two species of the region, Pinus strobus (Joyce and Rehfeldt, 2013) and Picea mariana (Joyce and Rehfeldt, 2017), but the species-specific models provide land managers with greater flexibility in obtaining seed. Nonetheless, our analog approach can be guided using lower thresholds (moderate or weak) for species that are thought to be generalist.
         We take the rationale that GCMs and RCPs largely vary in the timing of climate change (Rehfeldt et al., 2012, 2014; Joyce and Rehfeldt, 2013), rather than if climate change will occur. Accordingly, given the variability among climate model projections and carbon emission scenarios, we chose to provide a consensus based on an average of 13 GCMs. Our focus is mid-century, as these projections would have higher certainty than longer timeframes (Fitzpatrick et al., 2018) and are within long-term timeframes of land management planning and lifespans of the organisms that occupy existing ecosystems.
         As a basis for discussing our approach, we consider case studies for four themes: management implications for the high latitudes of Canada's boreal forest where climate change is projected to be most pronounced, climate novelty in the Great Basin of western United States, conservation concerns in Mexico�s Transvolcanic region, and assisted migration to accommodate shifts in forest composition. Maps contained in the Supplementary Material provide additional natural resource implications for diverse geographic regions. [Editor's note: There is no paywall and it is highly recommended to at least scroll through the Supplementary Material to view the geographically diverse maps.]
         Management actions suitable for no analog climates are largely unexplored. As shown repeatedly in the paleoecologic record (e.g., Ackerly, 2003), plant associations change as, presumably, competitive interactions among species readjust. Perhaps, therefore, a 'wait and see' or 'let nature take its course' approach would be the most reasonable. However, these strategies would have to be weighed against risks to threatened and endangered species and ecosystem services. Assisted migration may be a critical component to ecosystem restoration for novel climates, but with no recent historical ecological context to the predicted climates [see Burke et al. (2018)], information is extremely limited to guide management (Mahony et al., 2017).
        PROS, CONS, AND ASSUMPTIONS: Our approach simplifies seed transfer by standardizing a large set climate variables that generalizes plant-climate adaptation. As a result, it is ideally suited to species for which genecological principles are unknown, at least until result of provenance tests on climatically disparate sites would be available. However, it is important to note that generalized approaches cannot provide the species-specific accuracy of genecology studies or species distribution models where particular variables have greater importance in defining trait variation in the case of genecology or presence or absence of a species in a particular region. All climate variables have equal weight, making our seed transfer approach broadly applicable to plants, but a degree of species-specific precision is lost. Further study will be needed to assess the nuances between species-specific versus generalized seed transfer. Analogs are defined according to genecological patterns of genetic variation in species with the steepest clines. For many species, therefore, our definitions will be overly conservative which, on the one hand, could unduly handicap managers, but, on the other, greatly reduces the risks associated with seed transfer and assisted migration.
        As discussed repeatedly, climate-based research carries two caveats when applied to plant ecology. While climate is the primary driver of plant adaptation, other environmental, evolutionary, and ecological factors can play important roles potentially affecting the persistence or transition of vegetation (e.g., Renne et al., 2019). This means that implementation of practical programs requires personnel intimately familiar with local topography, soils, and ecological requirements of the target species (e.g., Winder et al., 2021). Also, ecological impacts projected from GCMs and their scenarios carry the risks associated with the uncertainty of such predictions (IPCC, 2014). Yet, managers have little recourse but to plow ahead.

  • USFS WEBINAR: "Using Assisted Migration" - by Brian Palik, Katie Nigro, and Bryce Adams, 11 April 2024.

      This VIDEO, with presentations by 3 research scientists of the U.S. Forest Service (U.S. Department of Agriculture), steps ahead of other federal agencies.

    Here one learns of the actual experience of USFS in "operationalizing" and "implementing" ASSISTED MIGRATION as a tool for climate adaptation of forests.

    This contrasts sharply with agencies within the U.S. Department of Interior — notably, the National Park Service (along with advisors from the U.S. Geological Survey). In those agencies, "preservation" rather than "management" is the norm.

    The first of 3 presentations was given by the USFS elder in assisted migration: Brian Palik. He was lead author of a 2022 paper: Operationalizing forest-assisted migration in the context of climate change adaptation: Examples from the eastern USA, Brian J. Palik, Peter W. Clark, Anthony W. D'Amato, Chris Swanston, Linda Nagel, October 2022, Ecosphere


  • Taking the Long View: Integrating Recorded, Archeological, Paleoecological, and Evolutionary Data into Ecological Restoration - by Rebecca S. Barak et al., 2015, International Journal of Plant Sciences
    EXCERPTS from the "Climate Change" section: Looking at the past is the best way to predict the effects of climate change on communities and ecosystems (Jackson 2007). Many North American plant species originated 20-40 million years ago and have thus been exposed to numerous periods of warming and cooling over that time period (Millar and Brubaker 2006). Understanding the trajectories of species and communities over past climate changes can help inform design and implementation of modern restorations. Paleoecological and evolutionary data—combined with modeling—allow for the reconstruction of past responses to climate change and can help contemporary restorationists plan for the future.
         Paleoclimate reconstructions paired with paleoecological data expand the range of conditions that supply perspective to restoration efforts. The paleoecological record contains examples of community stability over thousands of years, despite climate change (Brubaker 1975; Minckley et al. 2011), as well as sometimes dramatic and rapid community changes in response to climate change (Grimm 1983; Umbanhowar 2004). There are also no-analog pollen records from the past during the late glacial periods of the Quaternary, from 17,000 to 12,000 yr ago (Williams and Jackson 2007). These communities contained species that still exist today but are no longer found together in ecological communities (Williams and Jackson 2007). Such communities also existed much more distantly in the past, for example, during the Paleocene-Eocene Thermal Maximum (PETM), a period of intense climatic change ca. 55.8 million years ago that is used as an analog for today's anthropogenic climate change, since warming during the PETM was also caused by elevated carbon dioxide emissions (Dietl and Flessa 2011; McInerney and Wing 2011). Studying plant macrofossils from before, during, and after the PETM, Wing and Currano (2013) determined that plant community composition during the PETM is distinct from that before or after. This reflects migration rather than extinction, since missing species reappeared in the fossil record following the PETM. That there was little evidence of mass extinctions during the warming of the PETM may provide some comfort to restoration ecologists today. However, it is unclear to what extent current warming will mirror that of the PETM, especially as contemporary rises in carbon dioxide emissions are occurring at much faster rates than during the PETM (McInereny and Wing 2011).
         Paleoecological and phylogeographic data, along with species distribution modeling, are being used to determine the locations of past climate refugia—areas where species survived periods of intense climate change—and to predict the locations of future refugia (Gavin et al. 2014). Management can be prioritized to conserve and/or restore these areas in preparation for further change (Millar et al. 2007; Shoo et al. 2013). Similarly, phylogenetic data can be used to determine species that are likely to be vulnerable to climate change. Willis et al. (2008) studied the phylogenetic signal of changes in species' abundance and flowering time after 150 yr, using data initially collected by Henry David Thoreau in Concord, Massachusetts. They found that lineages with flowering times that did not track with climate change were declining and in danger of local extirpation. Thus, phylogeny, along with historical data, could be used to identify vulnerable species that would be unlikely to adapt (through evolution or plasticity) to changing climates and prioritize those species for interventions, such as assisted migration (Vitt et al. 2010).
         Historical and modeling data can also be used to identify locations for establishing neonative communities, defined as restoring species to an area where they were found in the past but do not currently occur (Millar et al. 2007). On a shorter timescale, dendrochronology in combination with climate projections can be used to identify the tree species and communities most vulnerable to changing climates (Williams et al. 2010). Fule (2008) recommends focusing management on forest habitats that are likely to persist through climate change—such as higher-latitude, higher-elevation sites—and using both historical and predicted climate data to engineer forests in areas where they are likely to persist in future climates.
         Several of these ideas, including climate refugia and corridors, are tied into the concept of conserving nature's stage. This strategy focuses on conserving geological diversity (geodiversity) as a surrogate for biological diversity (Beier et al. 2015). Geodiversity is strongly tied to biological diversity, and conservation of geodiversity may help to mitigate species losses due to climate change (Gill et al. 2015; Lawler et al. 2015). Ensuring that restoration areas include geomorphic heterogeneity may be one way to prepare for a changing climate. Appropriate species (the actors on the stage) may be added as climates change (Comer et al. 2015). Conserving the stage will create diverse habitats for evolution in future climate regimes (Lawler et al. 2015).

  • Projected distributions of novel and disappearing climates by 2100 AD - by John W. Williams et al., 2007, Proceedings of the National Academy of Sciences

       ABSTRACT: Key risks associated with projected climate trends for the 21st century include the prospects of future climate states with no current analog and the disappearance of some extant climates. Because climate is a primary control on species distributions and ecosystem processes, novel 21st-century climates may promote formation of novel species associations and other ecological surprises, whereas the disappearance of some extant climates increases risk of extinction for species with narrow geographic or climatic distributions and disruption of existing communities.

    Here we analyze multimodel ensembles for the A2 and B1 emission scenarios produced for the fourth assessment report of the Intergovernmental Panel on Climate Change, with the goal of identifying regions projected to experience (i) high magnitudes of local climate change, (ii) development of novel 21st-century climates, and/or (iii) the disappearance of extant climates. Novel climates are projected to develop primarily in the tropics and subtropics, whereas disappearing climates are concentrated in tropical montane regions and the poleward portions of continents. Under the high-end A2 scenario, 12-39% and 10-48% of the Earth's terrestrial surface may respectively experience novel and disappearing climates by 2100 AD. Corresponding projections for the low-end B1 scenario are 4-20% and 4-20%. Dispersal limitations increase the risk that species will experience the loss of extant climates or the occurrence of novel climates. There is a close correspondence between regions with globally disappearing climates and previously identified biodiversity hotspots; for these regions, standard conservation solutions (e.g., assisted migration and networked reserves) may be insufficient to preserve biodiversity.
         By the end of the 21st century, large portions of the Earth's surface may experience climates not found at present, and some 20th-century climates may disappear. The combination of high CO2 concentrations, still-extensive ice sheets in Greenland and Antarctica, and current orbital and land-ocean configurations are geologically unprecedented. Already, CO2 concentrations exceed any recorded for the last 650,000 years and, without a substantive intervention, are projected to increase to 540-970 ppm (140-263% relative to 2000 levels) by 2100 AD. Global mean temperatures are projected to increase by 1.4-5.8 degrees C by 2100 AD, with decreases in diurnal and seasonal temperature ranges and spatially variable changes in precipitation. It is increasingly likely that some end-21st-century climates will include conditions not experienced at present ('novel' climates) and that some present climates may disappear.
         This conceptual framework is reinforced by observed ecological responses to the last deglaciation, which were characterized by large changes in species ranges, and, in places where past climates apparently lacked modern analogs, the development of species associations and biomes with no modern counterpart. Metaanalyses indicate already detectable responses to 20th-century temperature rises, with range shifts averaging 6.1 km per decade toward the poles. Dispersal limitations may cause species responses to lag rapid climate change, promoting the formation of disequilibrial relationships between species distributions and climate. . . Rapid changes further enhance extinction risk by increasing the rate of climate change relative to the capacity of species to adjust by migration and colonization.
         Different ecological risks are associated with the prospect of novel versus disappearing climates. Novel temperature regimes, combined with changes in precipitation, may lead to novel species associations and other unexpected ecological responses, as has occurred in the past. Because the pre-Industrial Revolution climate system was already in a warm state, further increases in temperatures are likely to be novel not just relative to the 20th century but also to climates for at least the last million years. Tropical species may be particularly sensitive to 21st-century warming because (i) tropical temperatures vary less than high-latitude temperatures at daily, seasonal, orbital, and tectonic timescales, and (ii) range size tends to decrease toward the equator (Rapoport's Rule), so that tropical species are more narrowly endemic in both geographic and climatic space. Ecosystem models suggest that Amazonia is at particular risk for increased fire frequency and loss of forest cover. The potential for ecological surprises in the tropics adds urgency to current conservation efforts.
         Disappearing climates increase the likelihood of species extinctions and community disruption for species endemic to particular climatic regimes, with the largest impacts projected for poleward and tropical montane regions. Many have warned that climate change may drive certain species and ecosystems to extinction, e.g., in high latitudes, the South African Fynbos, and neotropical cloud montane forests. Our analysis places these regional alarms in a global context and goes further by showing that, in many cases, these climates may disappear entirely from the global set of end-21st-century climates. The areas of disappearing climates closely overlay regions identified as critical hotspots of biological diversity and endemism, including the Andes, Mesoamerica, southern and eastern Africa, Himalayas, Philippines, and Wallacea. In these areas, elevated risks of extinction are likely, as is the disruption and disaggregation of extant communities. Even with a conservative estimate of dispersal constraints, dispersal limitations greatly increase the risk that species will experience the loss of extant climates or the occurrence of novel climates. Efforts to conserve biological diversity in the face of climate change, e.g., by establishing dynamic networks of connected reserves that can facilitate species migrations or "rewilding" or otherwise assisting species migrations, may help overcome dispersal limitations. However, for those regions, communities, and species whose 20th-century climates lack 21st-century analogs anywhere globally, such approaches will be insufficient. Furthermore, because of the spatial segregation between novel and disappearing climates, species at risk of extinction due to disappearing climates are unlikely to be well positioned to take advantage of new climatic regimes.

  • The Influence of Paleoclimate on Present-Day Patterns in Biodiversity and Ecosystems - by Svenning et al., 2015, Annual Review of Ecology, Evolution, and Systematics
    P. 565 - Modeling studies suggest that we should expect disequilibria not just in assemblage composition (Dullinger et al. 2012a, Normand et al. 2013) but also in ecosystem structure, with tree line advances lagging behind climate for 100s to 1000s of years (Chapin & Starfield 1997, Normand et al. 2013). . . . The existence of paleoclimatic legacies also has important implications for conservation actions. These legacies indicate that species are often not able to track climate changes and point to the need for considering assisted migration as a tool to preserve biodiversity and sustain or restore ecosystem functioning under future climate change (Lunt et al. 2013). This will particularly be the case for the broader landscape and in particular in human-impacted and/or lowland areas where it will be most difficult for species to migrate fast enough to track climate change, as already seen (Bertrand et al. 2011). However, as active relocation will be unfeasible for much of biodiver- sity, there will be a strong need for protecting areas that offer good local possibilities for climate tracking or are likely to act as climatically stable refugia (Ackerly et al. 2010, Loarie et al. 2009).
         P. 566 - Importantly, the majority of studies of biodiversity and ecosystem patterns still do not consider the potential role of paleoclimate in codetermining the observed patterns, despite its potential importance in many cases. For example, this is true for many studies that rely on species distribution modeling to test ecological hypotheses or for conservation assessments (e.g., to assess risks from future climate change). The strong evidence for paleoclimatic legacies in species distributions have implications for how such modeling should be implemented. Notably, in forecasting studies it is important to avoid approaches that strongly rely on species ranges being in equilibrium with the current environment (e.g., De Marco et al. 2008); at the minimum, a critical assessment should be made of the extent to which such an assumption is valid in every given case and careful consideration given to the consequences of any violations.

  • Will Plant Movements Keep Up with Climate Change? - by Richard T. Cortlett and David A. Westcott, 2013, Trends in Ecology and Evolution.
    ABSTRACT: In the face of anthropogenic climate change, species must acclimate, adapt, move, or die. Although some species are moving already, their ability to keep up with the faster changes expected in the future is unclear. 'Migration lag' is a particular concern with plants, because it could threaten both biodiversity and carbon storage. Plant movements are not realistically represented in models currently used to predict future vegetation and carbon-cycle feedbacks, so there is an urgent need to understand how much of a problem failure to track climate change is likely to be. Therefore, in this review, we compare how fast plants need to move with how fast they can move; that is, the velocity of climate change with the velocity of plant movement.
        EXCERPTS: Paleoecological studies show that movement was a near universal response to past changes in climate and many species have moved in recent decades in response to rates of climate change that are apparently unprecedented in the Holocene. However, some plant species failed to keep up with the generally slower warming at the end of last glacial period and most plant populations have tracked recent warming only partly or not at all. Failure to track climate change is expected to have a large impact on growth and survival, leading to plant extinctions and a reduction in the strength of the terrestrial carbon sink.
         No plant extinctions have so far been attributed to recent climate change and only one species, the previously widespread Picea critchfieldii, is known to have become globally extinct during the Late Pleistocene from natural climate change. In vertebrates, however, the strong association between low rates of local endemism and high velocities of climate change since the last glacial maximum is most easily explained by increased extinctions when species fail to track climate change. Moreover, the association is strongest in amphibians, the most poorly dispersed group, and weakest in the relatively mobile birds. Although there has not yet been a similar study for plants, these results suggest that we are underestimating the number of species lost to natural climate change and, thus, the importance of movement velocity in buffering against extinction.

  • Forests of the Past: A Window to Future Changes - by Petit, Hu, and Dick, 2008, Science.
    EXCERPTS: .... When fossil and genetic data are combined, much information can be acquired about the whereabouts of small populations during the last glaciation and the trajectories of postglacial population spread. Recent studies that applied this integrative approach have offered new insights. For example, some temperate and boreal trees apparently survived the Last Glacial Maximum in periglacial environments probably tens of kilometers from ice sheets and even in ice-free areas north of ice sheets. Thus, it appears that small populations of trees can endure extreme climatic conditions for tens of thousands of years.

    However, these studies also imply that the capacity of trees to keep up with the rate of future warming is probably more limited than suggested by previous estimates from fossil data. Extremely fast tree migrations during the early Holocene were inferred from the fossil records of certain tree species, on the assumption that northern refugia did not exist during the Last Glacial Maximum. On the basis of more recent fossil and DNA studies, it appears that the actual rates may be an order of magnitude lower, e.g., <100 m/year for two North American deciduous tree species). These estimates are far below what would be necessary for species migration to track future climatic warming (3000 to 5000 m/year), raising interest in the possibilities of "assisted migration" — the translocation of populations to areas where future climate might be favorable...

    ... Although local evolutionary responses to climate change are likely to have occurred with high frequency, there is no evidence for change in the absolute climate tolerances of species. Thus, future extinctions of tree species in response to climate change are probable, especially if their geographic distribution or climatic range is already highly restricted. Here again, the retrospective approach could be illuminating. Europe lost at least 89 tree genera during the climatic transitions of the Late Tertiary to the Quaternary. A key question is whether past extinctions took place during glacial or interglacial periods. If extinctions had taken place mostly during interglacial periods, this would support pessimistic views of the consequences of future global warming on population and species survival. However, extant Asian and American congeners of extinct European tree species are less cold-tolerant than currently widespread European trees. This suggests that most extinction events took place during glacial rather than interglacial periods. In contrast, a 320,000-year history of vegetation and climate in Hungary showed that species extinctions clustered near times of high climate variability. This interpretation is consistent with the case of a now-extinct North American spruce, Picea critchfieldii, which was abundant during the Last Glacial Maximum but vanished during the last deglaciation, at a time of rapid climate change....

  • The Influence of Climate Variability and Change on the Science and Practice of Restoration Ecology - by Donald A. Falk and Constance I. Millar, 2006, chapter 17 in Foundations of Restoration Ecology, ed. Donald A. Falk et al.
    EXCERPTS: Assisted migration (AM) exemplifies new, strategic responses that have been proposed to maintain biological diversity through a period of climate change (Stone 2010). As the literature summarized earlier demonstrates, all species move in space and time throughout their ecological and evolutionary history, often in response to shifting climate. However, several factors raise concerns that the ability of many species to migrate in response to changing climate may be constrained under contemporary conditions. The first of these is the sheer pace of climatic change (IPCC 2014a). Depending on the rate of change (and recalling that mean temperature is only one of many climate dimensions), many species may not be able to migrate quickly enough on their own (fig. 17-8). Many other factors complicate this equation, especially landscape barriers to species movement (large multilane highways), natural and anthropogenic habitat fragmentation and degradation, absence of biotic dispersal vectors, and increased competition from non- native species (Wilcove 2008; Vitt et al. 2010).

  • Climate Change and Paleoecology: New Contexts for Restoration Ecology - by Constance I. Millar and Linda B. Brubaker, 2006, in Foundations of Restoration Ecology, ed. Donald A. Falk et al.
    EXCERPTS: PAGE 327: Beyond these two features, however, other conditions associated with ecological sustainability did not occur. At subregional scales within the Sierra Nevada, species diversity changed at timescales of centuries to millennia. Similarly, individual species ranges and population abundances shifted, often drastically. An example is giant sequoia (Sequoiadendron giganteum). Currently limited to small and disjunct groves between 1,500 and 2,100 m in the southwestern Sierra Nevada, giant sequoia's range over the past 10,000 to 26,000 years included the eastern Sierra Nevada (Mono Lake, Davis 1999a), and locations in the western Sierra Nevada that are both well above (2,863 m, Power 1998) and below (1,000 m in current chaparral shrubland, Cole 1983; and 54 m at Tulare Lake in the California Central Valley, Davis 1999b) its current range. Giant sequoia did not appear in its current range until 4,500 years ago and did not reach modern abundance there until about 2,000 ago, that is, the age of the oldest living individuals (Figure 15.9) (Anderson and Smith 1994).

    PAGE 329: Coast redwood (Sequoia sempervirens) is another example. Currently rare, it has fluctuated in population extent and abundance following both long (millennial) and short (century-decadal) cold/warm cycles. Redwood was even more sparsely distributed than at present during climate periods when coastal fog did not develop and temperatures were hotter or cooler relative to present (Heusser 1998; Poore et al. 2000). Redwood expanded during mild, equable parts of interglacials when ocean temperature and circulation influenced development of coastal fog.

    PAGE 329: For instance, Juniperus expanding in Great Basin rangelands has been considered an exotic invasive, and measures have been taken to remove plants. These changes appear, rather, to be adaptive responses to climate change (Nowak et al.1994). Other things being equal, an ecologically informed conservation action would be to encourage, not thwart, juniper expansion.

    PAGE 330: Although changes in population size and distribution may be natural responses to climate change, causes are often difficult to discern in practice. Lags in adjustment and other disequilibria between population distributions and climate mean that population increases or decreases may not be synchronous with climate change, especially during periods when rapid climate changes occur over short periods, making difficult the search for mechanistic causes (Jackson and Overpeck 2000). Because individual plants, unlike animals, cannot "pick up and move" (intragenerational), they migrate and shift in distribution by dying in some areas while expanding in others (intergenerational). These may be messy on the landscape — with patchiness and irregularity characteristic — making the effects difficult to evaluate while they're happening. Causes may be attributed readily to other proximal factors, such as to insects and pathogens, or anthropogenic effects, such as fire suppression, even where climate is the ultimate underlying factor.

    A challenging question for restoration ecology becomes, "What is the native range of a species?" To define the range of a species is the basis for monitoring its condition, understanding favorable habitat and ecological interactions, diagnosing threats and risks, determining restoration targets, and indicting species as "exotic" (Jackson 1997). Viewed against historic changes in distribution and natural flux, the native range of a species must be considered a transient and dynamic process itself, readily capable of moving in space as climate shifts over the landscape. Recognizing that non-equilibrium conditions exist and vegetation lags occur means that, like Lewis Carroll's Red Queen, vegetation chases a target (climate) that is itself changing.

    PAGE 332: Section head: "Restoration or Realignment?" The discussions above prompt reevaluation of restoration assumptions and goals. If sustainability is to remain a guiding concept in restoration ecology, its interpretation would better focus on sustaining future options for flexibility and adaptation to changing conditions, rather than attempting to recreate stable conditions that resist change. In practice, rather than emphasizing historic ranges, or predisturbance species assemblages, compositions, structures, and landscape patterns, sustainability might instead embrace landscape macrodynamics that have characterized populations and species over long timeframes. These include, for instance, the ability to shift locations significantly, fragment into refugia, expand or contract in range, coalesce with formerly disjunct populations, alter dominance relations, foster non-equilibrium genetic diversities, and accommodate population extirpations and colonizations — all in response to changing regional and global conditions.

    This does not imply, however, that "anything goes" in restoration. Adaptation is not chaotic, although stochastic processes play important roles. Populations and species respond and adapt to external forces of climate, invasives, and disturbance regimes with definable relationships and patterns; these can be better defined by restoration science, and mimicked in restoration practice. Rather than restoring past conditions, the challenge may be realigning systems to present and anticipated future conditions in such a way that they can respond adaptively to ongoing change (Millar and Woolfenden 1999b).

    Realignment will require an understanding of relevant prehistories as well as changing influences on population dynamics over time in the restoration region. Modeling (quantitatively or qualitatively) these conditions as a trajectory forward into the present and future, including known or anticipated changes in climate as well as other environmental changes, allows target conditions for a realigned population to be developed.

    PAGE 333: Another example of realignment comes from a conservation assessment of Monterey pine (Pinus radiata), currently a rare species with three small California coastal populations and two Mexican island populations. Each population is suffering significant declines from human threats, and conservation plans have been designed to restore these populations. All plans focus on improving conditions of the extant populations. Another approach to restoration derives from examining Quaternary dynamics of the species (Millar 1999). Analysis of Monterey pine paleorecords and paleoclimatologic data suggests that the species has a repeating metapopulation behavior that responds sensitively to fluctuations in climate. Under favorable climates, Monterey pine responds via colonization of many small, disjunct populations extensively along the California and Mexican coast, while during unfavorable climates, the species contracts to small networks of few populations. This process appears to have been repeated many times in Monterey pine's history.

    Monterey pine occurred in the past in coastal northern California locations, as far as 600 km from the closest current native population. In this region, Monterey pine has been planted for landscaping, where it has naturalized widely, eventually spreading into parks and nature reserves. In these locations, the species is considered an unwanted exotic and is aggressively removed as part of restoration projects.

    Based on analysis of Monterey pine's paleoecology, a realignment strategy was proposed as a supplemental restoration approach for the species (Millar 1998). The core of the idea is that Monterey pine would be encouraged to persist in certain areas on the north coast rather than being removed as an exotic pest. These locations are defined as areas where Monterey pine has naturalized, overlaps its historic range under similar climates at present, and includes floristic associates found in Monterey pine fossil assemblages. Such realignment locations are considered "neonative" sites for Monterey pine.

    PAGE 335 Section head: "Global Warming and Restoration Ecology": The specter of global warming has raised much concern in conservation communities. As we now understand, this is not something coming in the future, but something we already are experiencing. At one extreme, the "Anthropocene" era of human-induced climate began 8,000 years ago with the spread of agriculture and its cumulative biotic feedback effects. Nested within this background, warming observed in the last 120 years is partly rebound in the Bond cycling events, superimposed on the longer periods of internal and orbital cycling to which Earth is inextricably bound, and partly induced by modern human effects. Abrupt climate change and vegetation response have been common in Earth's history. On the one hand, this is comforting in that most species, whose roots extend into the Tertiary, must be at least somewhat adapted to the rates of change occurring now. Certain responses, such as massive landscape mortality events, range expansions, minor and major population extirpations, shifts in native ranges, or changes in community composition, may be expressions of landscape-scale resilience and realignment to changing external forces. Accommodating these factors — if we choose to accept them — will require rethinking our concepts about what and where native habitat is, what are "healthy" population sizes, what are causes of changes in population size, and when is change acceptable and appropriate. Society may choose not to accept such consequences and manage instead for other desired conditions. In such cases we will benefit by knowing that our management and conservation efforts may run counter to natural process, and thus restoration efforts may require continuing manipulative input to maintain the desired conditions. The lessons implied from paleoclimatology and paleoecology suggest that making friends with physical and ecological change is an important prerequisite to effective stewardship. Incorporating these ideas into new restoration ecology science and practice will require considerable thought, discussion, experimentation, and research in coming years.

    PAGE 336 from "Summary" section Rather than restoring historic, "pre-human-disturbance" conditions, we may better help species persist into the future by realigning populations with current and future anticipated conditions, and providing options to cope with uncertain futures with certain high variability. The capacity for populations to grow, decline, migrate, colonize, even extirpate, has determined species survival under past conditions of rapid change. Many situations thwart this capacity at present, including fragmentation, urbanization and development, static land-use policies (including conservation measures such as reserves, easements, etc.), and even rigid conservation philosophies that hold species hostage to specific locations and conditions. Understanding that species have coped with change in the past suggests that restoration sciences have opportunities to assist species cope with the dynamics of the current world.

  • Deep-Time Lags: Lessons from Pleistocene Ecology - by Connie Barlow, 2009, chapter in Gaia in Turmoil: Climate Change Biodepletion, and Earth Ethics in an Age of Crisis, edited by Eileen Crist and H. Bruce Rinker, 2009, MIT Press.
    EXCERPTS: ... I spent three years examining the genesis of that paper [D.H. Janzen and P.S. Martin, 1982, "Neotropical anachronisms: The fruits the gomphotheres ate," Science 215: 19�27] and exploring how its "deep-time" perspective has inspired subsequent research projects in evolutionary ecology and conservation biology. I worked my findings into a popular book, The Ghosts of Evolution: Nonsensical Fruit, Missing Partners, and Other Ecological Anachronisms (2001). One section of the book used the deep-time perspective to re-examine the circumstances of perhaps the world's most endangered species of conifer tree: the Florida torreya (Torreya taxifolia). It occurred to me that torreya's desperate plight owed to its failure to migrate north (perhaps for want of a seed disperser) from its Ice Age refuge in the Florida panhandle to habitat better suited to the tree's needs in peak interglacial times. That better habitat would likely have been the core of torreya's range during previous interglacials: the southern and central Appalachian Mountains.
         As it turns out, I was not the first to make this suggestion. Bill Alexander, forest historian at the Biltmore Gardens of Asheville, North Carolina (in the central Appalachian Mountains), observed his garden's own grove of Florida torreya, and concluded that North Carolina seemed more conducive to the well-being of this conifer than was northern Florida (personal communication). In a 1990 article, botanist Rob Nicholson speculated, "Is Torreya an early victim of global warming and a precursor of a new wave of inexplicable extinctions?" How prescient he was! Thanks to a host of recent scientific papers (e.g., Barlow and Martin 2005; McLachlan et al. 2007; Hoegh-Guldberg 2008) and popular articles (e.g., Fox 2007; Nijhuis 2008; Marris 2008), Florida torreya has become a "poster plant" for alerting the public and scientists alike to the lurking dangers of global warming and to the consequent need for what has come to be known as assisted migration....
         ... Assisted migration as a conservation tool is both fascinating and frightening for anyone focused on plants. It is fascinating because endangered plants can be planted by whomever so chooses, with no governmental oversight or prohibitions — provided that private seed stock is available and that one or more private landowners volunteer suitable acreage toward this end. This cheap-and-easy route for helping imperiled plants is in stark contrast to the high-profile, high-cost, and governmentally complicated range recovery programs for mobile animals, like gray wolf, lynx, and California condor. Assisted migration frightens for precisely the same reasons it fascinates: anybody can do it, for good or ill, and with care or abandon. Its promotion could undermine decades of public education about the dangers of nonnative plants, as well as more recent efforts to promote the concept of wildlands corridors and connectivity. Still, in an age of deforestation, severe habitat fragmentation, and rapid global warming, assisted migration as a plant conservation tool should not be ignored....

  • Paleoecology meets genetics: deciphering past vegetational dynamics - by Feng Sheng Hu, Arndt Hampe, and Remy J. Petit, 2009, Frontiers in Ecology Environ.
    EXCERPTS: Genetic data compensate for some of the shortcomings of the paleoecological approach. Recent surveys of DNA polymorphisms yield new insights into past vegetational dynamics and help address key paleoecological questions. However, studies that truly integrate genetics and paleoecology are rare. This paper highlights some of the recent developments in this field, rather than providing a comprehensive review of all the relevant literature. We focus on tree taxa with extensive fossil records that can be compared with marker-based genetic surveys (for a discussion focusing on adaptive traits, see Davis et al. 2005). We first briefly explain how ice-age refugial populations and their post-glacial recolonization left such durable genetic imprints on modern-day tree populations. We then review case studies that provide genetic insights into the locations of glacial refugia and the spatial patterns of postglacial recolonization. We discuss the consequences of past population dynamics on the genetic structure (eg variation in allelic frequency and genetic diversity) of extant trees, as well as the implications for conservation. During glacial episodes, temperate and boreal tree species were primarily restricted to areas far south of the continental ice sheets, although small populations of some species apparently also survived in periglacial (the outer perimeter of a glacier) environments and in high-latitude areas that were free of glaciers. At the end of each glacial episode, refuge populations responded to climatic amelioration and expanded their distributions to form interglacial plant communities, including those we see on the landscape today. . . Refugial tree populations that have persisted through multiple glacial cycles tend to have highly divergent gene pools. They are therefore potential priorities for the conservation of diversity and evolutionary heritage. . . Latitudinal patterns of genetic diversity and divergence should be taken into consideration in the current debate over the possible advantages of assisted migration in response to climate change. . . Some tree taxa, such as Picea glauca and Pinus banksiana (jack pine) in North America, went regionally extinct in the areas of their main glacial refugia during postglacial range shifts (Jackson et al. 1997). Massive diversity losses must have occurred at the trailing edges; today, therefore, their southern populations may not have a greater diversity than that of northern populations.

  • Conserving Biodiversity Under Climate Change: The Rear Edge Matters - by Arndt Hampe and Remy J. Petit, 2005, Ecology Letters.
    EXCERPTS: Here, we argue that rear edge populations, defined as those populations residing at the current low-latitude margins of species' distribution ranges, are disproportionately important for the long-term conservation of genetic diversity, phylogenetic history and evolutionary potential of species and that their investigation and conservation deserve high priority. . . The value of relict populations at the low-latitude margins of many species' distribution ranges has remained largely unperceived by conservation biologists. Some glacial relicts have been included in regional or national red lists, but neither research nor conservation programs seem to have been dedicated to rear edge populations per se (although Lesica & Allendorf (1995) have considered the conservation value of peripheral populations in general). Here, we outline three areas in which further development of research and conservation measures appears particularly necessary. Hence, specific conservation measures will have to be identified to effectively preserve these relict populations.

  • "Paleoecology and the Assisted Migration Debate: Why a Deep-Time Perspective Is Vital" - online essay by Torreya Guardian Connie Barlow, February 2011.
    Connie Barlow (with assistance from Russell Regnery) has posted a short, 11-point summary essay that aggregates the data and develops strong scientific reasoning in favor of assisted migration for Torreya taxifolia. The essay also advocates a shift in the foundational paradigm from assuming 1491 is the proper time-standard for assessing native range to a "deep-time" perspective grounded in a paleoecological understanding that native ranges for all plants in temperate latitudes of the Northern Hemisphere have undergone substantial altitudinal and/or latitudinal migrations that have tracked changes in climate during the past several million years of Pleistocene glacial and interglacial cycles.

  • "Deep-Time Lags: Lessons from Pleistocene Ecology" by Connie Barlow, in Gaia in Turmoil: Climate Change Biodepletion, and Earth Ethics in an Age of Crisis, edited by Eileen Crist and H. Bruce Rinker, 2009, MIT Press.
    Torreya Guardians founder Connie Barlow contributed a chapter on the importance of a "deep time" perspective for conservation biologists and biodiversity activists coming to grips with the extinction crisis in an age of rapid climate change. The plight of Torreya taxifolia and the work of Torreya Guardians are used as the key example of "Assisted Migration in a Time of Global Warming".

  • "The Torreya taxifolia USF&WS Recovery Plan Process: An Opportunity to Shift to a Deep-Time Perspective of Native Habitat" - comments and suggestions by Connie Barlow, 12 May 2010
    Submitted to the U.S. Fish & Wildlife Service officer in charge of updating the Endangered Species Recovery Plan for Torreya taxifolia. EXCERPT: "If one agrees with the widely held premise that the habitat along the Apalachicola River in northern Florida and southern Georgia served as a premier 'pocket refuge' for many temperate-zone species during the peak glacial episodes of the past several million years, then one is moved to revamp formal ecological definitions of 'native habitat' and 'native range' in ways that comport with a perspective that geographic range for temperate zone species of the eastern United States has always and must continue to shift in tandem with climate change. With respect to Torreya taxifolia, the premise is that this species is endangered today because it is a 'glacial relict.'"

  • "Climate Change and Forests of the Future: Managing in the Face of Uncertainty,", by Constance I. Millar et al., Ecological Adaptations, 2007.
    EXCERPT: Establish 'neo-native' forests. Information from historical species ranges and responses to climate change can provide unique insight about species responses, ecological tolerances, and potential new habitats. Areas that supported species in the past under similar conditions to those projected for the future might be considered sites for 'neo-native' stands of the species. These may even be outside the current species range, in locations where the species would otherwise be considered exotic. For instance, Monterey pine (Pinus radiata), endangered throughout its small native range, has naturalized along the north coast of California distant from its present native distribution. Much of this area was paleohistorical range for the pine, extant during climate conditions that have been interpreted to be similar to expected futures in California. Using these locations for 'neo-native' conservation stands, rather than removing trees as undesired invasives, is an example of how management could accommodate climate change. (p. 2148)
  • "Conservation Paleobiology: Leveraging Knowledge of the Past to Inform Conservation and Restoration", by Gregory P. Dietl et al., 2015, Annual Review of Earth and Planetary Sciences.
    EXCERPTS: Humans are now the principal architects of environmental and biotic change on planet Earth. In response, conservation paleobiology has emerged over the past decade as a powerful intellectual approach and effective tool for acquiring longer-term perspectives on changes in species, communities, and ecosystems, beyond the limited time frame of direct human observation, and applying this information to pressing conservation issues. The overarching goal of conservation paleobiology is to use geohistorical analysis to develop knowledge, principles, and tools for conserving and restoring biodiversity and ecosystem services in the face of climate change and other human impacts.
         Research in conservation paleobiology generally takes two approaches. A near-time approach uses the relatively young fossil record, primarily from the past 2 million years, to provide a context for present-day conditions, focusing largely on extant species. Such geohistorical records are used to (a) define baselines to compare conditions before and after disturbance, (b) examine the response of species and ecosystems to recent natural and anthropogenic perturbations, (c) develop a narrative of the historical range of variability, (d ) set realistic targets for restoration, (e) differentiate between anthropogenic and nonanthropogenic change, and (f) recognize ecological legacies that can be explained only by events or conditions that are not present in the system today. A deep-time approach uses the much older geologic record as an archive of repeated natural experiments. This approach permits analysis of biotic responses to system perturbations of diverse kinds and magnitudes, some of which approximate present-day disturbances or those predicted for the near future, such as substantial climate warming and ocean acidification. The deep-time approach also permits testing of biotic responses under a broader array of conditions than is available in the modern world or its recent past.
         Predicting changes in species' distributions under different scenarios of climate change is a major objective in conservation biology. Paleoecological data can be used to detect shifts in geographic distribution of species in response to recent climate change. For example, bones from now-abandoned breeding sites of Adelie penguins on Anvers Island, Antarctic Peninsula, show that these sites were occupied exclusively by that species back through the Little Ice Age (1400-1850 CE) and that the gentoo and chinstrap penguins now breeding there have expanded their ranges to this region only within the past 50 years, presumably in response to climate warming. The fossil record is also sometimes the sole means to indicate where species occurred in the past, beyond their present-day geographic range. For example, Greenstein & Pandolfi (2008) used fossil occurrences in seacliffs along the coast of Western Australia to document how reef-building coral species shifted their distribution in response to climate change since the Late Pleistocene. This understanding enabled them to forecast coral response to future climate warming. Tropical-adapted coral species are predicted to migrate south along the coast of Western Australia and persist in temperate refugia. Knowing where and which coral species might migrate is critical to developing effective management practices that enhance their chances of survival in an era of climate warming.
         Paleobiological studies are useful to (a) recognize that ecological conditions have in fact changed, (b) establish the timing of the change and thereby disentangle possible anthropogenic from natural drivers, and (c) in the best cases, establish "what was natural" or at least what biological conditions prevailed at some specified time in cultural history.
  • "Paleoecological Insights on Conservation of Biodiversity: A Focus on Species, Ecosystems, and Landscapes" by Paul A. Delcourt and Hazel R. Delcourt in Ecological Concepts in Conservation Biology 1998.
    EXCERPTS: "Regional projections of future greenhouse-gas induced climatic warming indicate that Picea rubens and Abies fraseri forests may become extinct in the southern Appalachians. . . Over glacial-interglacial cycles, climatic and environmental changes have restructured biological systems, resulting in disassembly and reassembly of communities, individualistic migrations of species, and changes in genetic diversity resulting from alternate restriction and release of refugial populations."
        "In this paper, we evaluate the applicability of two contrasting ecological approaches to conserving biodiversity in the Appalachian Mountains in light of past and possible future shifts in the ecotones between alpine tundra, boreal coniferous forest, and temperate deciduous forest. Toward this end, we summarize available plant-fossil data from late-Quaternary sites in order to evaluate a previously developed model of changing landscape states, and then we project future shifts in ecotones in a greenhouse world based on scenarios from two different atmospheric circulation models."     "Below the climatic Picea-Abies/deciduous forest ecotone, isolated montane populations of Picea and Abies persist in locales of suitable edaphic and microclimatic conditions, such as streamside ravines, topographic depressions with pockets of cold-air drainage, and wetlands and alluvial glades with impeded water flow or perched water tables. These edaphic outliers of Piecea-Abies forest extend below their climatic ecotone by as much as 400 m in the Great Smoky Mountains and by 500 m in the central Appalachians."
        CONCLUSIONS: "The strong focus of many conservation biologists on immediate recovery of small populations of rare and endangered species diverts attention from the probability that widespread environmental changes in the near future may compound other, more local threats to continued existence of species that are narrowly adapted to specific habitats. . . In many instances extinction of rare species is likely to result from loss of suitable habitat and inability of species to migrate rapidly. Even species that are now common may be vulnerable to local or global extinction if environmental changes cross physiological thresholds of tolerance."

  • "Paleoecology and 'inter-situ' restoration on Kauai, Hawaii" by David A. Burney and Lida Pigott Burney, in Front Ecol Environ 2007; 5(9): 483-490, doi 10.1890/070051.
    Review paper of ongoing work on Kauai that actively uses a pre-historic baseline (prior to first human arrival one- or two-thousand years ago) for developing standards for plant restoration ecology on the island. A great example that there is a continuum between "historic" and "Pleistocene" standards for "restoration" and "rewilding." A must-read for those who cling to "historic native range" standards for opposing on principle "assisted migration."

  • "Return of the Ericads: Students Dig and Reestablish a Prehistoric Species", by Michael Heim, Journal American Rhododendron Society, Winter 2010
    Michael Heim is a science teacher at Lac Courte Oreilles Ojibwe High School, Hawyard WI, whose students planted in May 2009 cloned cuttings from a very rare eastern native: the evergreen Box Huckleberry, Gaylussacia brachycera. The 2 page, photo-rich PDF of this article is a fascinating look at "rewilding" of an endangered species, based on a "deep-time" perspective in which "native" is regarded as including a plant's presumed preglacial regional distribution. In a March 5 comment posted on the Torreya Guardians site, Heim reports that he and his students have also planted cuttings from clones of Torreya taxifolia and Taxus floridana on the same tribal forest lands next to the school in northern Wisconsin, thus signifying another citizen-initiative of assisted migration, based on a deep-time understanding of native range.

  • Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems, by Anthony D. Barnosky et al., Science, 10 February 2017.
    EDITOR'S NOTE: excerpted below are the paragraphs that deal with managed relocation and the overall context that is forcing a shift in "conservation paradigms."

    EXCERPTS: The paleobiological approach can further improve species distribution models by incorporating information on trait-environment connections and/or persistent associations of taxa�that is, groups of two or more taxa that co-occur in fossil localities distributed widely through time and space. Current models rely primarily on climatic parameters alone to estimate niche space. Such paleontologically enhanced species distribution models can also be helpful in informing efforts to relocate species into suitable environments, ranging from managed relocation experiments that aim to save threatened species to choosing which trees to plant in urban and suburban landscaping in order to jump-start dispersal in anticipation of future climatic conditions.
         Rather than attempting to hold ecosystems to an idealized conception of the past, as has been the prevailing conservation paradigm until recently, maintaining vibrant ecosystems for the future now requires new approaches that use both historical and novel conservation landscapes, enhance adaptive capacity for ecosystems and organisms, facilitate connectedness, and manage ecosystems for functional integrity rather than focusing entirely on particular species. Scientific break-throughs needed to underpin such a paradigm shift are emerging at the intersection of ecology and paleobiology, revealing (i) which species and ecosystems will need human intervention to persist; (ii) how to foster population connectivity that anticipates rapidly changing climate and land use; (iii) functional attributes that characterize ecosystems through thousands to millions of years, irrespective of the species that are involved; and (iv) the range of compositional and functional variation that ecosystems have exhibited over their long histories.
         Conservation success will also increasingly hinge on choosing among different, sometimes mutually exclusive approaches to best achieve three conceptually distinct goals: maximizing biodiversity, maximizing ecosystem services, and preserving wilderness. These goals vary in applicability depending on whether historical or novel ecosystems are the conservation target. Tradeoffs already occur — for example, managing to maximize certain ecosystem services upon which people depend (such as food production on farm or rangelands) versus maintaining healthy populations of vulnerable species (such as wolves, lions, or elephants). In the future, the choices will be starker, likely involving decisions such as which species are candidates for managed relocation and to which areas, and whether certain areas should be off limits for intensive management, even if it means losing some species that now live there. Developing the capacity to make those choices will require conservation in both historical and novel ecosystems and effective collaboration of scientists, governmental officials, nongovernmental organizations,the legal community, and other stakeholders.
         JOSHUA TREE NATIONAL PARK (as example): Climatically suitable areas may shift northward and upslope, but the slow migration rate of Joshua trees limits their ability to track their suitable climate space, especially because one of their dispersal agents — Shasta ground sloths — is extinct. In this case, the fossil information implies that conserving Joshua Tree National Park in its present ecological state may not be possible because of climate-triggered species turnover, including loss of its namesake species and colonization by currently exotic species. The implication is that conserving Joshua tree ecosystems may require more active management in protected areas outside the national park, acquisition of new lands, and perhaps targeted planting. This landscape-scale management of Joshua trees could nurture the adaptive capacity of the species across its range, even if the national park loses its suitable habitat, while still maintaining the wilderness character of Joshua Tree National Park if wilderness character depends more on the low level of local human impacts than on the presence of Joshua trees.
        Even with ideal corridors, however, species will not all respond in concert as climate changes, a lesson made clear by the fossil record. Some species will move quickly, some slowly, and some not at all, and species will key on different aspects of global change, such as temperature, humidity, or biotic interactions. Effective corridors will maximize the opportunities for such natural adjustments to proceed, even though the end result will be species assemblages almost certainly different than current or historical ones.

    PALEOECOLOGY SPECIFIC TO FORESTRY (helpful for assisted migration)

  • "Past and future global transformation of terrestrial ecosystems under climate change" - Connor Nolan and 41 coauthors, 31 August 2018, Science.

    EXCERPTS: ...Pervasive ecosystem transformations occurred in response to warming and associated climatic changes during the last glacial-to-interglacial transition, which was comparable in magnitude to warming projected for the next century under high-emission scenarios. We reviewed 594 published paleoecological records to examine compositional and structural changes in terrestrial vegetation since the last glacial period and to project the magnitudes of ecosystem transformations under alternative future emission scenarios. Our results indicate that terrestrial ecosystems are highly sensitive to temperature change and suggest that, without major reductions in greenhouse gas emissions to the atmosphere, terrestrial ecosystems worldwide are at risk of major transformation, with accompanying disruption of ecosystem services and impacts on biodiversity....
         Beyond observations of recent and ongoing change, models indicate ecosystem transformation under climate projections for the 21st century. These include dynamic global vegetation models (3, 17), species distribution models (18), and comparison of the multivariate climate distance between biomes with that between modern and future climates (19). However, the capacity for assessing the magnitudes of ecosystem transformation under future climate scenarios is limited by the difficulty of evaluating model performance against empirical records, particularly when projected climate states are novel (19, 20).
         Paleoecological records of past ecological responses to climate change provide an independent means for gauging the sensitivity of ecosystems to climate change. High-precision time-series studies indicate that local and regional ecosystems can shift rapidly, within years to decades, under abrupt climate change (21-23), but sites with such detailed chronologies are scarce. In this study, we used published reports to compile a global network of radiocarbon-dated paleoecological records of terrestrial vegetation com- position and structure since the Last Glacial Maximum (LGM), 21,000 years before the present (yr B.P.) (24). Most postglacial warming happened 16,000 to 10,000 yr B.P., although it commenced earlier in parts of the Southern Hemisphere (25, 26). Global warming between the LGM and the early Holocene (10,000 yr B.P.) was on the order of 4 to 7 degrees C, with more warming over land than oceans (26, 27). These estimates are roughly comparable to the magnitude of warming that Earth is projected to undergo in the next 100 to 150 years if GHG emissions are not reduced substantially (28). The magnitudes of changes in vegetation composition and structure since the last glacial period (LGP) provide an index of the magnitude of ecosystem change that may be expected under warming of similar magnitude in the coming century (29). Although the rate of projected future global warming is at least an order of magnitude greater than that of the last glacial-to-interglacial transition (26), a glacial-to-modern comparison provides a conservative estimate of the extent of ecological transformation to which the planet will be committed under future climate scenarios....
         ...Europe and eastern North America experienced unusually large temperature changes since the LGM, owing to depressed temperatures near the large ice sheets, and these regions show substantial compositional and structural changes since the LGP. However, results from other parts of the globe indicate that widespread ecosystem changes were driven by much smaller temperature changes (fig. S3). ...
         Under the RCP 8.5 scenario [business as usual, IPCC], the rate of warming will be on the order of 65 times as high as the average warming during the last deglaciation (26). Furthermore, the warming between the LGP and the Holocene occurred within the range of previous glacial and interglacial temperatures, whereas projected future changes will exceed those experienced over the past 2 million years (26). Although many ecological responses (e.g., species migration, colonization, and succession) will likely lag behind climate changes, ecosystem transformations will often be accelerated by disturbance and mortality events, land use, and invasive species (7�15)....
         We therefore conclude that terrestrial vegetation over the entire planet is at substantial risk of major compositional and structural changes in the absence of markedly reduced GHG emissions. Much of this change could occur during the 21st century, especially where vegetation disturbance is accelerated or amplified by human impacts (7). Many emerging ecosystems will be novel in composition, structure, and function (42), and many will be ephemeral under sustained climate change; equilibrium states may not be attained until the 22nd century or beyond. Compositional transformation will affect biodiversity via disintegration and reorganization of communities, replacement of dominant or keystone species, pass-through effects on higher trophic levels, and ripple effects on species interactions (16, 43)....

  • "Forest Responses to Changing Climate: Lessons from the Past and Uncertainty for the Future", 2000, Donald H. DeHayes et al., book chapter in Responses of northern U.S. forests to environmental change.
    EXCERPT: Continent-wide changes in distribution and abundance of plant taxa are species-specific, consistent with Gleason's (1926) individualistic concept of plant-species responses (Davis, 1983; Jacobson et al., 1987). Contrary to popular belief, modern communities are not highly organized, finely tuned units representing long periods of co-evolution among species. Rather, present communities are merely transitory combinations of taxa that have been responding individualistically to continual and sometimes major climate changes (Hunter et al., 1988). [includes "Eastern White Pine Case Study"] Paleoecological evidence shows that eastern white pine made its first post-glacial appearance in Virginia (Craig, 1969), perhaps moving in from a full glacial location on the exposed continental shelf. It reached northern New England by 10,000 years ago (Davis and Jacobson, 1985), the central Great Lakes region by 9,000 years ago (Brubaker, 1975), and Minnesota and western Ontario by 7,000 years ago (Jacobson, 1979; Bjorck, 1985). Eastern white pine reached its northernmost extent about 4,000 years ago, with areas of high abundance shrinking substantially and shifting southward thereafter. This coincides with climate cooling that has allowed boreal taxa to move southward. Another factor in the late-Holocene decline in eastern white pine is the decrease in frequency of fire. Further details of these late-Holocene changes may be found in Jacobson and Dieffenbacher-Krall (1995). The western range limit of eastern white pine occurs today where precipitation equals evapotranspiration (Transeau, 1905). Unless its habitat is manipulated by human activity, white pine does not thrive when conditions become too cool or moist, for example, at the southern margins of the boreal forest in northern New England and adjacent Canada where disturbance by fire may be too infrequent for widespread establishment of seedlings. The current abundance of eastern white pine in the Northeast results largely from abandonment of farmland during the last 150 years.
         Paleoecological studies of the later Holocene show that the boreal forest of eastern Canada developed only in the past 6,000 years (Webb, 1987) and that hemlock has been abundant in the forests of the eastern Great Lakes-New England region for that same period of time (Fig. 14.4). Other data show that southern populations of spruce (Picea spp.) shifted from Canada into the northern tier of states from Maine to Minnesota in the past 1,000 to 1,500 years, accompanied by a general decrease in abundance of eastern white pine that has continued to the present (see Fig. 14.2). Small populations of balsam fir (Abies balsarnea [L.] Mill.) were scattered throughout the northeast during most of the Holocene, but they, too, expanded recently to form the spruce-fir forests of today. The spatial array of changes has been influenced by variations in importance of fire (Foster, 1983) and other disturbances.
        Northern populations of most temperate and boreal zone species have no difficulty tolerating climates more than 5�C warmer on an annual basis. The only exception may be with trees having substantial winter chilling requirements. For example, red maples from Massachusetts exhibit sporadic and delayed spring budbreak and have poor survival when grown in Florida (Perry and Wang, 1960). This possibility should be examined carefully because some climate models project that much of the future warming will be experienced in the winter (Woodward, 1992). Observations of horticultural plantings also suggest that species can be grown in climates far warmer than any place in their natural range. Coupled with the relatively rapid rate of predicted climate warming, these data and experiences highlight the possibility that many species distributions may not simply shift northward or upward, but may actually remain competitive in their current locations and actually expand their distributions.
         A greater concern is that a warmer and drier environment may reduce germination and seedling survival. The most sensitive stage of a tree's life is the beginning. Losses in this period are very high, owing mostly to conditions that are inhospitable at this vulnerable stage. On sites that are prone to drought or lethal temperatures, such as south-facing slopes, higher temperatures would exacerbate losses. The area affected by these lethal agents would increase to some degree. Furthermore, germination could be reduced or unfavorably delayed in species with unmet cold stratification requirements. These unknown factors related to seed germination and success of the seedling stage in forest trees all contribute to uncertainty in predicting future forest composition.
         Many species found a "glacial refugium" in the southern Appalachian region. If the Appala- chian Mountains were aligned east-west instead of north-south, perhaps many of these species would have been unable to migrate far enough southward to endure the climatic cooling experienced during glaciation.
         Uncertainty exists about the nature and extent of future climatic change and its effect on migration of forest tree species. Although it is tempting to speculate that climate change may be too rapid for forest tree species to successfully migrate or that large gaps may be created that can restrict species dispersal, historical evidence indicates that climate changes in the past have been more rapid than changes projected for the next few centuries without any great restriction to species movement.

  • PALEO DATA USED TO PREDICT SEVERE 21st CENTURY PROBLEMS FOR TREES SHIFTING RANGES: "Pushing the Pace of Tree Species Migration", by Eli Lazarus and Brian McGill, 27 August 2014, PLOS One. Editor's note: This paper deals exclusively with tree species whose seeds are wind-dispersed. The outlook for trees with animal-dispersed seeds is even gloomier. EXCERPT:
    Field measurements of typical seed dispersal distances would suggest that tree fronts migrate across a landscape by a process of local diffusion, at rates significantly slower than the velocities reflected in pollen data. But seeds are occasionally carried long distances from their source by wind or by animals. If those seeds mature into trees that in turn dispense seeds, the plant species may migrate at rates that far exceed diffusive propagation. Existing models of tree migration by long-distance dispersal produce migration rates between approximately 100 to 200 m yr-1. A global analysis of temperature-change rates across geographic gradients and biomes finds that temperate broad-leaf and mixed forests, which includes the North American taxa that spread by wind-blown dispersal, will need to shift at a mean velocity of 350 m yr-1. These required migration rates appear to exceed the fastest modeled rates, but may fall within the ranges empirically observed in the last deglaciation. Migration rates barely sufficient to track with climate, combined with the well-documented effect that landscape fragmentation further impedes migration, points to the apparently unequivocal conclusion that climatic change will outpace the migration of wind-dispersed tree species through human-dominated landscapes. One of the few known cases in which climate-driven species migration was impeded comes from Europe, where east-west mountain ranges and the Mediterranean Sea prevented trees and plants from advancing far enough south during Pleistocene glaciation, resulting in a high proportion of extinction. By extension, understanding how human fragmented landscapes interfere with migration rates might mean the difference between minimal extinction rates and massive extinction rates in next few hundred years.

  • PALEOECOLOGICAL DISTRIBUTION OF E. NORTH AMERICA TREES: "Molecular Indicators of Tree Migration Capacity Under Rapid Climate Change", by McLachlan et al., in Ecology, 2005. CONTENT: Excellent review of paleocological investigations using paleo-pollen, macrofossils, and genetic data to ascertain (a) locations of glacial refuges of N.A. temperate trees during the last glacial maximum, and (b) the northward path and speed of movement as the peak glacial episode began to wane some 18,000 years ago. EXCERPT: "Molecular evidence suggests that American beech (Fagus grandifolia) and red maple (Acer rubrum) persisted during the late glaciation as low-density populations, perhaps within 500 km of the Laurentide Ice Sheet. Because populations were closer to modern range limits than previously thought, postglacial migration rates may have been slower than those inferred from fossil pollen. Our estimated rates of <100 m/yr are consistent with model predictions based on life history and dispersal data, and suggest that past migration rates were substantially slower than the rates that will be needed to track 21st-century warming."

    EXCERPTS: This paper integrates recent efforts to map the distribution of biomes for the late Quaternary with the detailed evidence that plant species have responded individualistically to climate change at millennial timescales. Using a fossil-pollen data set of over 700 sites, we review late-Quaternary vegetation history in northern and eastern North America across levels of ecological organization from individual taxa to biomes, and apply the insights gained from this review to critically examine the biome maps generated from the pollen data. Higher-order features of the vegetation (e.g., plant associations, physiognomy) emerge from individualistic responses of plant taxa to climate change, and different representations of vegetation history reveal different aspects of vegetation dynamics. Vegetation distribution and composition were relatively stable during full-glacial times (21,000 to 17,000 yr BP) [calendar years] and during the mid-to late Holocene (7,000 to 500 yr BP), but changed rapidly during the late-glacial period and early Holocene (16,000 to 8,000 yr BP) and after 500 yr BP. Shifts in plant taxon distributions were characterized by individualistic changes in population abundances and ranges and included large east-west shifts in distribution in addition to the northward redistribution of most taxa. Modern associations such as Fagus-Tsuga and Picea-Alnus-Betula date to the early Holocene, whereas other associations common to the late-glacial period (e.g., Picea-Cyperaceae-Fraxinus-Ostrya/Carpinus) no longer exist. Biomes are dynamic entities that have changed in distribution, composition, and structure over time. The late-Pleistocene suite of biomes is distinct from those that grew during the Holocene. The pollen-based biome reconstructions are able to capture the major features of late-Quaternary vegetation but downplay the magnitude and variety of vegetational responses to climate change by (1) limiting apparent land-cover change to ecotones, (2) masking internal variations in biome composition, and (3) obscuring the range shifts and changes in abundance among individual taxa.
         Plant taxa responded individualistically to past environmental change. This observation is a central feature of late-Quaternary vegetation history and fits well with Gleason's view of plant communities (Gleason 1917, 1926). In a classic example (Davis 1976, Davis 1981b), Fagus and Tsuga today have closely associated distributions yet their histories of range and abundance changes differ. Tsuga pollen percentages were below 1% in eastern North America until 14,000 yr BP in the central Appalachians, increased northward along the Appalachian corridor, and by 12,000 yr BP had begun to increase in southern New England. Fagus abundances were low until 14,000 yr BP, increased briefly in the southeast between 14,000 and 12,000 yr BP, but did not expand into New England until after 9,000 yr BP. The distributions of Fagus and Tsuga did not attain their modern overlap until the mid-Holocene. Many other taxa that co-occur today — e.g., Picea and Abies, Quercus and Castanea, and Fagus and Acer — have had similar types of differences in history. The temporal changes in taxon distribution and abundance illustrate how plant species respond individualistically to climate change at continental to regional scales, so that most plant associations have little or no permanence.

  • CLASSIC PALEOECOLOGY PAPER ON PAST FOREST RESPONSES TO CLIMATE CHANGE: "Range Shifts and Adaptive Responses to Quaternary Climate Change", by Margaret B. Davis and Ruth G. Shaw, 2001, Science.
    Excerpts: "Although all the tree species that remain in our flora shifted or contracted ranges, adapting to climate changes in the past, there are reasons to question whether these processes will occur as readily during the present period of climate change.... Range shifts are the most conspicuous, and best documented, response of woody species to Quaternary climate. As the climate warmed at the end of the last glacial interval, tree populations became established at higher latitudes. These range extensions are called 'migrations,' although individual plants, unlike animals, cannot move to follow changing climate. Rather, occupation of new regions occurs through passive seed dispersal and establishment of seedlings in sites where conditions permit. The patterns of migration during ing the past 25,000 years are individualistic, with the entire range of some tree taxa displaced to new latitudes, e.g., spruce (Picea spp.) (Fig. 1A). In contrast, others expanded from glacial refuges, e.g., oak (Quercus spp.) (Fig. 1B). Migration rates and the routes of migration also differed among taxa (1, 11, 12). In regions that were never glaciated, many species and genera continued to grow at the same latitude, shifting from one range of elevations to another and expanding or contracting population size."

  • CLASSIC PALEOECOLOGY PAPER BY MARGARET DAVIS: "Lags in Vegetation Response to Greenhouse Warming", by Margaret B. Davis, 1989, Climatic Change.
    Excerpts: ... Changes in the geographical distributions of plants are also to be expected in coming decades. For each degree centigrade warming, ranges expand 100 km northward, while southern populations retreat. On the scale of tens of kilometers, and thousands of years, geographical limits of tree species have tracked past climatic changes quite closely (Webb, 1986; Prentice, 1986; Woods and Davis, 1989; Davis et al., 1986a). The question of interest is whether plant species can disperse and establish new populations rapidly enough within the next 100 years to occupy habitats that will become available, given warming of several degrees magnitude, and a rate of climatic warming that is at least one order of magnitude more rapid than any known previous climatic change. The fossil record has provided useful information about the rate at which trees were able to advance across the landscape during the Holocene. The rates measured by the appearance of pollen in quantity at different latitudes represent actual (not potential) rates of range extension, averaging 10-45 km per century over long time periods (Firbas, 1949; Davis, 1981; Huntley and Birks, 1983)....

  • CLASSIC FORESTRY PAPER ON THE DIRE PROBLEM OF THIS CENTURY'S SPEED OF CLIMATE CHANGE: "Adaptation, Migration or Extirpation: Climate Change Outcomes for Tree Populations", by Sally N. Aitken et al., in Evolutionary Applications, 2008. EXCERPT: "Findings of relatively slow tree migration rates in response to historical changes in climate (potentially < 100 meters per year) are unfortunate in light of model predictions of how fast tree species will need to migrate to track current climates under climate change scenarios. Tests of 14 combinations of GCMs and global SDMs show up to 100% of the models predicting migration rates of 1000 meters per year or higher to be necessary to track habitat under 2x CO2 climate forcing."

  • HOW NORTH AMERICAN TREES SPECIES AND BIOMES SHIFTED FROM PEAK GLACIAL TO WARM TIMES: "Late-Quaternary Vegetation Dynamics in North America: Scaling from Taxa to Biomes" - John W. Williams et al., Ecological Monographs, 2004. Excerpts: "This paper integrates recent efforts to map the distribution of biomes for the late Quaternary with the detailed evidence that plant species have responded individualistically to climate change at millennial timescales. We show how the individualistic shifts in range and abundance for plant taxa scale upward to cause (1) compositional shifts within plant communities, (2) appearances and disappearances of novel plant associations, and (3) changes in the position, area, composition, and structure of biomes. Modern associations such as Fagus-Tsuga and Picea-Alnus-Betula date to the early Holocene, whereas other associations common to the late-glacial period (e.g., Picea-Cyperaceae-Fraxinus-Ostrya/Carpinus) no longer exist."

  • "RELICT" SPECIES RESTRICTED TO DISJUNCT AND SMALL RANGES BY PLEISTOCENE GLACIALS: In 2012 an exemplary paper was published by forest researchers that demonstrated how a paleoecological perspective is vital to understand the importance of "assisted colonization" as a management tool in this century's time of rapid climate shift: "Projections of suitable habitat under climate change scenarios: Implications for trans-boundary assisted colonization", by Ledig, Rehfeldt, and Jaquish, 2012, American Journal of Botany.
        Importantly, this paper also diminishes fears that such relicts might become invasive: "In part, objections to assisted colonization rest on the fear that exotic translocated species will become invasive and compete with native species or that they will carry new pests or on the esthetic argument that such movements result in a homogenization of the flora (Seddon et al., 2009; Ricciardi and Simberloff 2009a, , 2009b; McLachlan et al., 2007). With regard to the issue of native vs. exotic, spruces have moved north and south across North America over geological time (e.g., discussion in Ledig et al., 2004)."     The focal species of this paper is Brewer Spruce, Picea breweriana, which is limited today to the Klamath region of coastal Oregon/California. The paper finds that projected climate change will necessitate the assisted movement of this unique spruce to coastal British Columbia in 2030 to 2060 and finally to the Yakutat coastal region of Alaska by 2090. Here is how the paper begins (citations eliminated):
    "The western United States was warm, subtropical forest in the Eocene (40 million years ago [Ma]). Above 50 degrees N, about the latitude of Vancouver, British Columbia, Canada, was the Arcto-Tertiary Forest. A species like dawn redwood (Metasequoia) was a common element of the Arcto-Tertiary Forest. Genera like bald cypress (Taxodium) and blackgum (Nyssa), now found only in the southeastern United States, grew along the interface of the Arcto-Tertiary Forest and the subtropical forest. Along the streams in the Arcto-Tertiary Forest were species similar to Port-Orford-cedar [Chamaecyparis lawsoniana (A. Murr.) Parl.] and coast redwood [Sequoia sempervirens (D. Don) Endl.],