Assisted Migration (Assisted Colonization, Managed Relocation)
Links to Journal and Magazine Articles
and Rewilding of Plants and Animals
in an Era of Global Warming
http://www.csmonitor.com/2005/0830/p08s02-comv.html
Click here for Proposed Standards for Assisted Migration of Plants.
Visit The Rewilding Institute.
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.
ABSTRACT: Managed relocation (MR) has rapidly emerged as a potential intervention strategy in the toolbox of biodiversity management under climate change. Previous authors have suggested that MR (also referred to as assisted colonization, assisted migration, or assisted translocation) could be a last-alternative option after interrogating a linear decision tree. We argue that numerous interacting and value-laden considerations demand a more inclusive strategy for evaluating MR. The pace of modern climate change demands decision making with imperfect information, and tools that elucidate this uncertainty and integrate scientific information and social values are urgently needed. We present a heuristic tool that incorporates both ecological and social criteria in a multidimensional decision-making framework. For visualization purposes, we collapse these criteria into 4 classes that can be depicted in graphical 2-D space. This framework offers a pragmatic approach for summarizing key dimensions of MR: capturing uncertainty in the evaluation criteria, creating transparency in the evaluation process, and recognizing the inherent tradeoffs that different stakeholders bring to evaluation of MR and its alternatives. [Ed. note: This paper is the product of the Managed Relocation Working Group project. Details of three species-specific case studies, including pro and con managed relocation of Florida Torreya, are described in a supplementary pdf.]
Report of 25 May 2009 multi-author paper in Proceedings of the National Academy of Sciences, which proposes a new management tool for choosing which species are most viable for relocation based on a series of social and ecological criteria—for example, how much is known about the biology, geographical distribution and the ecological uniqueness of the species, as well as how easy they are to catch and move. Social factors, such as cultural importance, financial impact and even the laws and regulations regarding the species, also are considered. Partially funded by the National Science Foundation (NSF), the working group is co-led by Jessica Hellmann and Jason McLachlan of the University of Notre Dame, Dov Sax of Brown University, and Mark Schwartz of the University of California at Davis. David Richardson of Stellenbosch University in South Africa led the writing of the paper. See also this Press Release on the paper.
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.
Lengthy news article that surveys the assisted migration debate, from its roots in a 2004 article in Wild Earth journal to citizen-activism, scientific backlash, and the beginnings of a worldview shift. The work of Torreya Guardians is highlighted, along with the August 2008 official filing, under the Endangered Species Act, of a request (by scientist Camille Parmesan) to undertake the first intentional movement of an animal species (an endangered butterfly) in response to shifting climate.
One of the top journals in science reports on the article (immediately below) that had been published in the other top science journal, plus coverage of the special session on assisted migration at the Ecological Society of America meeting in August 2008. Torreya Guardians is presented as taking the action lead in pressing for a rethinking of how biodiversity is best protected.
This 2-page article in America's top science journal has spurred enormous coverage and debate over the topic of what was once known as "assisted migration". Click here for news reports of the article:
Content: Right now this is just a skeleton website, as the group goes about its work. But after it achieves a product, estimated for autumn 2009, this will be a key site to watch. Right now, you can find a list of group leaders and members on that site. Check out their LIST OF PUBLICATIONS AND MEDIA REPORTS on this topic.
Hoegh-Guldberg says, "If we are to take the latest climate science seriously, then our current conservation strategies will not work for the majority of the species. To be blunt, they need to change. Even under the mildest rates of climate change, the habitat of many species will contract. Consequently, the future for many species and ecosystems is so bleak that assisted colonisation might be their only chance of survival."
A lengthy article featuring Camille Parmesan, first advocate for assisted migration among professional conservation biologists. Lots of excellent details on butterflies and other species threatened by climate change. Mentions work of Torreya Guardians in assisting Torreya taxifolia tree seedlings to venture northward in July 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)
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."
Zimmer's survey includes the context of the Ricciardi and Simberloff paper (directly above), and Jessica Hellman's comment on that paper, where she says, "Is the alternative just to forsake a species?" she asks. "I just don't want to sit back and say, 'Oh the world is going to hell'."
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.
A richly illustrated PHOTO-ESSAY, with links to a complete chronology, of the REWILDING ACTION that Torreya Guardians undertook for 31 potted seedlings. A writer and a photographer commissioned by Audubon magazine documented the action (which will probably be published in a summer 2009 issue of Audubon.
Detailed news report of "the first successful test case of assisted colonization". In 1999 and 2000, scientists introduced populations of two species of butterfly miles north of their then-current range in England. A just-published paper reports the results:
Source: Willis, S.G. et al. 2009. Assisted colonization in a changing climate: a test-study using two U.K. butterflies. Conservation Letters DOI: 10.1111/j.1755-263X.2008.00043.x
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.
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.
Torreya Guardians (and others) are invited to post comments on whether the original term, "assisted migration," should be replaced with the term more recently proposed, "assisted colonization."
Revisits a previous blog on the possible extinction of California's Joshua Tree, owing to an inability to disperse and thus track climate changes. In this blog, Clarke mentions the work of Torreya Guardians in assisting migration of a critically endangered tree in eastern North America.
Interview of scientists and managers working in Joshua Tree National Park; prospects for the extirpation of Joshua Trees in the park as climate changes; the role of extinct ground sloths in past seed dispersal of this tallest of all yuccas. Audio interview of a trip to a cave looking for sloth dung.
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.
Content: The paper begins, "The Torreya Guardians are trying to save the Florida torreya from extinction. . . 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. . . If circumventing climate-driven extinction is a conservation priority, then assisted migration must be considered a management option. . . 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."
Content: Superb and lengthy science reporting on the above paper that appeared in Conservation Biology, with much additional information, insights, and arguments culled from the authors and other scientists and conservation managers. Highlights issues related to speed of migration (past evidence as well as estimates of future needs) and regional changes in climate. An article referenced within the report by Jason McLachlan et al., is also important to read: "Molecular Indicators of Tree Migration Capacity Under Rapid Climate Change" in Ecology, 2005, Vol 86, pp. 2088-98.
Content: References a forthcoming paper to be published in the journal Conservation Biology that encourages debate on the topic, by Mark Schwartz, Jason McLachlan, and Jessica Hellman
Content: Distinguishes history of inter- v. intra-continental invasive species in assessing the risks. Concludes that fish and crustaceans may pose a high risk. "We conclude that the risk of AM to create novel invasive species is small, but assisted species that do become invasive could have large effects."
Content: Great intro for popular audiences; shows lab experiments with insects in climate simulated settings.
Endangered Species Act invoked by Center for Biological Diversity to protect pikas threatened by global warming in the alpine peaks home in mainland U.S. No mention yet of assisted migration for the subspecies of pika trapped on warming mountain tops.
News report on the 18 July 2008 paper in Science by Hoegh-Guldberg et. al (above).
Great overview of looming problems for ecosystems (such as the Everglades) and species (such as Mountain Pica), some of which are already happening. No mention of assisted migration, of course, as this degree of human intervention would be a very delicate issue for the "wildest" of landscapes, especially for formally designated wilderness areas.
A 4.3 degree F. area-specific rise in temperature over the past century has affected plants in this sacred spot of environmentalism in Massachusetts. Notably, the plants hardest hit are those that did not alter their spring flowering time in tandem with the shift in earlier seasonal warming.
The IUCN has issued a report on "climate change susceptible" species. "Assisted migration" is mentioned as one of the possible management responses, as well as enlarged biological preserves and focussing on entire ecosystems, not merely individual species.
Content: 37 Bolson Tortoises (larger than a desert tortoise) were moved from a private ranch in Arizona to protected lands in New Mexico where they are being bred and managed expressly for "rewilding" into their former habitat.
Content: Aldabran Giant Tortoises used as proxies for the Mauritius giant tortoises that had been exterminated. "Rewilding" a small island near Mauritius with these giant tortoises.
Barlow and Martin 2004 proposed that Torreya taxifolia might have gotten trapped in its peak-glacial pocket reserve (in northern Florida) for lack of its coevolved seed disperser, and thus was unable to geographically respond to the warming interglacial climate. The above paper suggests that another taxon of gymnosperm that thrived (along with genus Torreya) in the Jurassic period might have suffered from an inability to easily track climate change when the seed-dispersing dinosaurs died out.
Download in PDF two articles, for and against assisted
migration of Torreya taxifolia, published as the featured
Forum in the Winter 2005 issue of Wild Earth. Download
the pro and con articles separately for printing on standard
size paper. Or, for viewing the 2-article Forum as it
appeared in publication (wide-screen, with all illustrations),
download the "Forum."
FOR assisted migration, by Connie Barlow & Paul Martin
ANTI assisted migration by Mark Schwartz
FORUM (both articles for wide screen)
Content: News report on how climate change will threaten animal and plant species; includes coverage of Torreya taxifolia and mentions Torreya Guardians.
Content: "Can a tree native to coastal British Columbia, given climate change, flourish in Fort Nelson? Can a tree native to the Interior live prosperously on Vancouver Island? Those are questions Greg O'Neill hopes to find answers for. O'Neill is a geneticist with Vernon's Kalamalka Forestry Centre, and is overseeing forestry's biggest climate change research trial in North America."
Content: Blogs and comments debate "assisted migration/colonization" with respect to snails; includes some case history of attempt to relocated endangered snails from New Zealand mainland to an island off NZ.
Content: Editorial in favor of assisted migration for endangered species.
Content: Advocacy and statement of conditions that merit assisted migration intervention for orchids
Content: Makes case for using the term "assisted colonization" rather than "assisted migration"; proposes three features for testing advisability of any particular species for such intervention: (1) their probability of extinction due to climate change, (2) their vagility, (3) and their ecological roles.
Content: Governmental publication in favor of assisted migration of tree species in anticipation of climate change.
Content: Effect of global warming on California blue oaks and other trees.
Content: Marine biologist highly skeptical of the merits of considering assisted colonisation for marine species.
Content: Professor Lesley Hughes, co-author of the 18 July 2008 paper in the journal Science (O. Hoegh-Guldberg et. al), is interviewed by the web news of her university. Also click on an AUDIO INTERVIEW with Professor Hughes (scroll down to 30 June 2008, "Climate Change Peril").
Content: The first advocacy article ("commentary") by prominent conservation biologists that proposes "rewilding" close-kin of some of the large mammals that went extinct in North America at the end of the Pleistocene, 13 thousand years ago by reintroducing close relatives or proxies.
Content: This is the long and fully developed version of the 2005 paper, by the same set of authors. Abstract: Large vertebrates are strong interactors in food webs,
yet they were lost from most ecosystems after the dispersal of modern
humans from Africa and Eurasia. We call for restoration of missing
ecological functions and evolutionary potential of lost North American megafauna using extant conspecifics and related taxa. We refer
to this restoration as Pleistocene rewilding; it is conceived as carefully
managed ecosystem manipulations whereby costs and benefits are
objectively addressed on a case-by-case and locality-by-locality basis.
Pleistocene rewilding would deliberately promote large, long-lived
species over pest and weed assemblages, facilitate the persistence and
ecological effectiveness of megafauna on a global scale, and broaden
the underlying premise of conservation from managing extinction
to encompass restoring ecological and evolutionary processes. Pleis
tocene rewilding can begin immediately with species such as Bolson
tortoises and feral horses and continue through the coming decades
with elephants and Holarctic lions. Our exemplar taxa would con-
tribute biological, economic, and cultural benefits to North America.
Owners of large tracts of private land in the central and western
United States could be the first to implement this restoration. Risks
of Pleistocene rewilding include the possibility of altered disease ecol-
ogy and associated human health implications, as well as unexpected
ecological and sociopolitical consequences of reintroductions. Estab-
lishment of programs to monitor suites of species interactions and
their consequences for biodiversity and ecosystem health will be a
significant challenge. Secure fencing would be a major economic cost,
and social challenges will include acceptance of predation as an over-
riding natural process and the incorporation of pre-Columbian eco-
logical frameworks into conservation strategies.
Content: Lengthy interview with Connie Barlow discussing the Pleistocene megafaunal rewilding concept. Very useful links to other related articles and audios at the end.
Content: Lengthy report on the author's visits to talk with some of the leaders in Pleistocene Rewilding movement.
Content: A long report of the rewilding of Europe's endangered native bison to a 500 acre preserve in Latvia that will also contain other surrogates for Pleistocene megafauna.
Content: Meshes "ecological anachronisms," conservation biology, rewilding of ecological proxies/analogs, and assisted migration/colonization, in a landmark paper that experimentally demonstrates the ecological viability and conservation value of introducing Aldabran tortoises to the oceanic island of Mauritius as ecological proxies (seed-dispersal agents) for Mauritian tortoises that were driven into extinction by humans.
Content: News report on the American Naturalist paper cited above.
Content: Editorial generally supportive of the August 2005 paper in Nature.
Content: Lots of quotes from Dr. Mark Schwartz on the assisted migration issue.
Lead author of the "Pleistocene Rewilding" paper originally published in Nature writes for a popular audience and responds to criticism that has emerged.
Proposes rewilding the endangered Asiatic lion into Europe.
Ongoing reports, news articles, and blog entries on this topic, posted at the The Rewilding Institute website.
Wikipedia entry, with photos and references, on this topic.
For those of us considering the importance of "assisted migration" of species impacted by climate change, or outright "rewilding" of species or surrogates to regions in which they lived thousands of years ago, this paper is something to ponder. Here the author proposes that the collapses of fisheries in the North Atlantic may be irreversible without infusion of new species diversity, and that much is to be gained (and little risked) by introducing North Pacific fishes into the North Atlantic. The deep-time discussion of "The Great Trans-Arctic [Marine] Biotic Interchange" (which began 3.5 million years ago when the Bering Land Bridge was transgressed by marine waters), is crucial reading for those of us working with entirely terrestrial biotas.
Interview published on the Action Bioscience website, an education resource of the American Institute of Biological Science
Useful blogpost and comments on the possibility of cloning frozen mammoth DNA from flesh or sperm.