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121-582: The Torreya Guardians is a self-organized group of conservationists dedicated to facilitating the assisted migration of the Florida torreya by rewilding it further north than its native range in Florida and Georgia . Founded in the early 2000s, the group is often mentioned as an instigator of the assisted migration of forests in North America for conservation and climate adaptation purposes. It

242-467: A glacial relict that had been unable to return northward after the glacial times ended, she expressed the need for citizen action in a 2010 article in Audubon Magazine . "Potted is the botanical equivalent of caged," she said. "I'm interested in preserving not just a species but its wildness." The two sides had come to a head in 2004 when the environmentalist magazine Wild Earth published

363-616: A completely different species of plant on which to lay its eggs, according to research presented at the Butterfly Conservation's seventh international symposium in Southampton.... "Every butterfly biologist who knew anything about the quino in the mid-1990s thought it would be extinct by now, including me," said Prof Camille Parmesan of the Marine Sciences Institute at Plymouth University...." In

484-584: A form of assisted migration already underway. Because the original plantings likely did not include the goal of helping the trees migrate northward in a warming climate, this form of unintended climate adaptation enabled by humans can be called inadvertent assisted migration . Jesse Bellemare and colleagues may have coined the term in a paper published in 2017: "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." A subcanopy tree native to

605-465: A laboratory environment to create desired responses based on their environments. Notable examples include a 1989 experiment which used stress conditioning via heat shock on rat kidneys to extend their safe cold storage time to 48 hours. More recently, stress conditioning is being studied as a potential solution for the preservation of coral reefs as they are continually exposed to ocean warming and acidification. Assisted gene flow (AGF) works to increase

726-411: A means for preventing extinction of species. As of 2023, however, there have been few examples of assisted migration projects underway: A review paper concludes, "Assisted migration was most common for plants (particularly trees), followed by birds, and was rarely implemented for other taxa." Assisted migration is a specific type of species introduction. Species introduction is any act of establishing

847-508: A monotypic genus, of very restricted range and specialized habitat." This species is notable in conservation history for being the first example of an endangered vertebrate that was experimentally translocated to a distant location (300 kilometers poleward) expressly because of climate change. By the time assisted migration trials began, the sole remaining original refuge for this species was inhabited only by captive-bred tortoises that had been reintroduced. The first trial began in 2016, with

968-580: A pair of detailed pro and con articles on what to do about the Florida torreya. Connie Barlow and paleoecologist Paul S. Martin wrote the essay in favor of moving the species, citing evidence that the Florida torreya had been pushed south during the previous ice age . When the ice retreated, this large-seeded, subcanopy tree had trouble migrating back north to cooler realms. For most of its history, therefore, this species of genus Torreya had not been native to Florida. Mark W. Schwartz, an American conservation biologist who had been researching and participating in

1089-450: A paper titled, "Endangered Quino checkerspot butterfly and climate change: Short-term success but long-term vulnerability?", the authors acknowledged the butterfly's surprising ability to utilize a new larval plant food in a cooler nearby habitat and concluded: "Quino appears resilient to warming climate. However, projections indicate that most or all of Quino’s current range in the USA, including

1210-586: A profession and are eager to assist an endangered plant. The volunteer in Cleveland, Ohio, Fred Bess, is a professional landscaper, and as of 2021 his set of Florida Torreya plantings hold the record for the farthest north seed production in a fully outdoor setting. In 2013, a journal article published in Conservation Letters described the actions of Torreya Guardians as a form of "citizen-initiated assisted colonization." The authors explained that

1331-512: A project for the pika did not occur. As for Joshua tree, in 2019 the U.S. Fish and Wildlife Service ruled against listing this desert plant as a "threatened" species, and California state government did the same in 2022. During this time, three U.S. Fish & Wildlife Service scientists aggregated existing research (including range shift climate modelling) into a report titled, "Examining the Past, Present, and Future of an Iconic Mojave Desert Species,

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1452-405: A rapidly changing climate—including helping iconic tree species ( Joshua Tree and Giant Sequoia , for which several parks are named) to move upslope or poleward faster than they can do on their own. The Torreya Guardians were founded in 2004 by Connie Barlow, an American science writer and amateur horticulturalist. The group is composed of citizens hailing from diverse professions, mostly based in

1573-469: A rare practice by conservation institutions, planting trees outside their native range is not illegal in the United States. Indeed, the horticulture trade has long been engaged in selling and planting both native and exotic plants with no legal limitations, except where governments have officially listed particular plants as invasive species in the United States . While endangered plants native to

1694-461: A review paper by seven researchers in the United States assessed shifts in what they called "conservation strategies for the climate crisis." Among the "novel strategies" surveyed was "climate-adaptive assisted migration." The team found that academic publications became less focused on the pros and cons of the concept through the years. Instead, more attention was given to modeling or mapping where particular species could be moved. While plants had been

1815-420: A separate Misplaced Pages page titled Assisted migration of forests in North America was launched in 2021 and made into a useful teaching tool for climate adaptation education and decision-making in the forestry profession. The remainder of this page therefore focuses on the topic of assisted migration in conservation biology and especially its applications for management of endangered species. Climate change

1936-400: A similar increase in temperature tolerance. Adaptation this slow would be insufficient for keeping up with expected future global warming if migration of new habitats is not an option. In addition to acclimatization and adaption, assisted evolution is an alternative to assisted migration that has been growing in popularity recently due to the worldwide coral reef crisis. Assisted evolution is

2057-445: A sister species, Monterey cypress , whose historically native range is nearby: on the opposite side of Monterey Bay. Hybridization is known to occur between the two endemics — as well as with a widely planted sister species native to Arizona: Arizona cypress . Other consequences of hybridization include the accumulation of deleterious genes, outbreeding depression, and genetic swamping. In the case of outbreeding depression which reduces

2178-474: A specialized niche, have such difficulty growing," he said in 2010, "that the chance of them becoming invasive is infinitesimally small." Primack explained that there is a much more serious danger: "that our efforts to move them will fail." In 2021 a "policy forum" article published in the journal Science reviewed the assisted colonization controversy. Mark Schwartz was one of the eight coauthors. The journal published an accompanying news article that focused on

2299-473: A species in a habitat it does not currently occupy. It often refers to a long-distance relocation, such as the accidental introduction of an invasive species from one continent to another, or the intentional relocation of a species in decline to a habitat where it can persist. By contrast, assisted migration acknowledges that the natural dispersal rate of many species may be too low to naturally respond to rapid human-caused climate change and instead focuses on where

2420-450: A their inability to colonize new areas fast enough. Though some argue that nature often responds to challenges more effectively in the absence of human intervention, others note that current climate change, itself, is a human intervention. Many species that would have been effective dispersers under slower, natural climate change may be left behind by more mobile species under current rates of human-caused climate change. Thus, through changing

2541-566: A tool for climate adaptation. Coast redwood (native to California) and Torreya taxifolia (native to Florida) are two examples. In 2022 a Canadian Forestry Service publication pointed to the success of horticultural plantings in British Columbia and Washington state , along with a review of research detailing redwood's paleobiogeography and current range conditions, as grounds for proposing that Canada's Vancouver Island already offered "narrow strips of optimal habitat" for extending

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2662-529: A viable management response to climate change. Those who wish to keep assisted migration on the table often note that the vast majority of historical species invasions have resulted from continent-to-continent or continent-to-island transportation of species and that very few invasions have resulted from the comparatively short-distance, within-continent movement of species proposed for assisted migration. For example, Mueller and Hellman reviewed 468 documented species invasions and found that only 14.7% occurred on

2783-561: Is Nicola Mitchell, an associate professor of conservation physiology at the University of Western Australia. She openly spoke to the International New York Times about the ethical imperative: Should humans just let nature run its course, thereby dooming this species to extinction because of climate change? "Or do we have an ethical responsibility" to act in its behalf? Mark Schwartz, a conservation scientist at

2904-537: Is an example of citizen-initiated citizen science . The Florida Torreya ( Torreya taxifolia) is an endangered tree of the yew family , Taxaceae , found in the Southeastern United States, at the state border region of northern Florida and southwestern Georgia . T. taxifolia became one of the first federally listed endangered plant species in the United States in 1984; the IUCN has listed

3025-524: Is an existential threat to the species. The hihi's current native habitat is becoming unstable due to rising temperatures, and suitable temperatures are shifting further south. Assisted migration is being considered as a means of ensuring the hihi can remain in its current natural habitat. Critics, however, argue the risks that are presented to the new host environments are not worth the potential benefits assisted migration may present. Mature horticultural plantings of trees northward of their native ranges are

3146-724: Is clear that climate change will drive many species extinct, and a traditional, land-preservation ethic will not prevent extinctions. Those wary of moving species instead suggest expanding networks of habitat corridors , allowing species to naturally migrate into newly suitable areas. Under the rates of climate change projected for the coming decades, however, even perfectly connected habitats will probably be insufficient. Species that cannot naturally keep pace with shifting climates will be at risk regardless of habitat connectivity. Evidence suggests that slowly evolving and slowly dispersing species (including species that are dispersal-limited due to habitat fragmentation ) will decline or go extinct in

3267-505: Is discussed in its own journals and from perspectives different from those of conservation biologists. This is, in part, because paleoecologists had already concluded that there were significant lags in northward movement of even the dominant canopy trees in North America during the thousands of years since the final glacial retreat. In the 1990s, forestry researchers had begun applying climate change projections to their own tree species distribution modelling efforts, and some results on

3388-592: Is expected to drive many species out of parts of their current ranges while creating new suitable habitats elsewhere. In order to avoid population declines and extinction, many species will need to either adapt or colonize newly suitable areas. Using a niche modeling approach, scientists have predicted that a failure to migrate or adapt will result in about a quarter of the world's species dying out this century under moderate climate change. The natural dispersal rates for many species are far slower than those needed to keep pace with projected habitat shifts in many regions of

3509-538: Is inherently controversial when proposed or used as a tool for helping native plants or animals adapt to ongoing climate change . The Routledge Handbook of Philosophy of Biodiversity , published in 2017, includes this mention of Torreya Guardians: When it comes to ecosystems, presumably the most oft-cited example of assisted migration concerns Torreya Guardians who transplanted seedlings of Florida Torreya ( Torreya taxifolia ) in North Carolina. The translocation

3630-481: Is known as composite provenancing. However, if the environmental gradient is well known, such as predictable changes in elevation or aridity, source populations should be ‘genetically matched’ to recipient sites as best as possible to ensure that the translocated individuals ae not maladapted. This strategy of moving species beyond their current range has been suggested for those that are severely threatened or endangered. By moving them outside their native range, hopefully

3751-691: The Torreya genus would migrate to higher altitudes when warmer average temperatures put them at risk. They saw in this a solution to the plight of the Florida torreya, and hypothesized that the tree would thrive if relocated to lands north of its historical range. They argued that torreyas would be better suited to survive in a cooler climate and that the species in California often was found on very steep slopes. Major American conservation institutions were unwilling to test their hypothesis. Plant assisted migration projects had never been implemented before in

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3872-534: The Atlanta Botanical Garden , who cautioned as well that the horticulturally derived seedlings planted by the citizen group might be genetically inferior to the wild genetics that her institution is safeguarding in ex situ plantings in Georgia. Action by Torreya Guardians in translocating an endangered tree poleward has been called "the best documented case of a managed relocation." While still

3993-551: The Endangered Species Act to implement their own assisted migration project outside established institutions. The Torreya Guardians saw North Carolina as particularly hospitable for the Florida torreya because trees of this genus have lived at the Biltmore Gardens , in nearby Asheville , for almost a century. Here can be found the second oldest surviving grove of horticulturally planted trees. In 2005

4114-551: The Great Barrier Reef are being interbred to test whether offspring display increased resistance to warmer living conditions. Increased resistance to warmer living conditions allow for the preservation of the Great Barrier Reef even as water temperatures continue to rise. Hybridization refers to the process where an egg and sperm from two different species can fertilize and produce young. Hybridization

4235-637: The Southeastern United States , at the state border region of northern Florida and southwestern Georgia . A self-organized group of conservationists called the Torreya Guardians was created in 2004 to undertake the assisted migration of this glacial relict tree by rewilding it in more northern parts of the United States . The controversy that developed was that the citizens used an exception (just for plants) in

4356-476: The U.S. Fish and Wildlife Service published a proposed rule in the Federal Register that would "revise section 10(j) regulations under the Endangered Species Act to better facilitate recovery by allowing for the introduction of listed species to suitable habitats outside of their historical ranges. The proposed change will help improve the conservation and recovery of imperiled ESA-listed species in

4477-645: The Biltmore Gardens donated 110 seeds to Lee Barnes, a member of the Torreya Guardians. Most of the seeds were donated to horticultural staff of botanical gardens northward. Three years later, the group purchased potted seedlings from a nursery in South Carolina, and then drove the plants to two sites in the mountains of North Carolina, where the torreyas were planted into regrowth forests on private lands. Such in-forest plantings represent

4598-550: The Endangered Species Act, while prohibiting citizen initiatives pertaining to imperiled animal species, "has encouraged citizens to undertake plant conservation, especially for charismatic plants threatened by climate change." Torreya Guardians was then described as having "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

4719-465: The Florida torreya samplings are thriving. In other states with an even colder climate, such as New Hampshire, the tree manages to survive, but is having more trouble growing than in warmer places. After about a decade of implementation, the group's results were mixed. The relocated tree's health varied across states. Some were harmed by summer droughts and harsh winters. However, many trees remain alive and are thriving in their new environment. As of 2023,

4840-578: The Joshua Tree." It was published in December 2020. No mention was made of any form of translocation, including assisted migration, for securing the species against future climate change. The stitchbird , also known as the Hihi, is a bird endemic to New Zealand. Changes in climate have shown to have a profound effect on the hihi's ability to thrive and reproduce. As a result, human caused climate change

4961-539: The Torreya Guardians explain that "there are no by-laws, officers, board, staff, overhead costs, dues, formal organizational structure, or physical location to this organization". On the topic of official communications, the Torreya Guardians website further notes that the organization "does not speak or take action as a group, but instead encourages subsets of those involved to post ideas and initiatives on this website and to help establish links with synergistic organizations and websites". According to member Clint Bancroft,

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5082-404: The Torreya Guardians network is mostly maintained by the work of the founder, Connie Barlow. Because the Torreya Guardians are a decentralized group, they do not have a systematic data-collection approach. Instead, participants share their ongoing results by word, photo, video, and sometimes in quantitative format for posting on the Torreya Guardians website. In some states, such as North Carolina,

5203-475: 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).... 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." Bioethics professionals have pointed to the actions undertaken by Torreya Guardians as an example of why assisted migration

5324-636: The United States Endangered Species Act of 1973 to begin their own assisted migration of a listed critically endangered species — even while the official recovery plan did not yet allow for it. By 2018 the citizens had accomplished documentation of species thrival in a dozen legacy horticultural plantings — including seed production and next-generation saplings at several sites in North Carolina. In 2018 their own plantings in Cleveland, Ohio, began producing seeds (turquoise star in image at right). Early scholarly debates on

5445-510: The United States for the purpose of conservation, so it was rejected. Instead, the United States Fish and Wildlife Service was trying to protect this species by managing the diseases affecting it in its native range at the time, with limited success. Since the species listing in 1984, the official conservation efforts undertaken in behalf of the Florida torreya centered first on collecting and rooting cut branchlets from specimens in

5566-465: The United States have more stringent controls than other plants, commercial nurseries can sell properly sourced (that is, horticulturally grown rather than wild) specimens so long as the sale is not across state lines ( interstate commerce ). Provided there is no monetary transaction, private citizens can legally carry or send horticulturally sourced specimens of listed endangered species. The nascent Torreya Guardians took advantage of this legal exception to

5687-502: The University of California, Davis, was quoted in the article. Speaking about the scale of biodiversity threats posed by climate change, versus using assisted migration as an adaptive strategy, Schwartz said: "To move enough species to resolve this threat basically seems untenable." Yet he also noted that climate-responsive translocations were more acceptable than another approach under consideration: initiating gene editing to make species more climate-proof. Lead scientist Mitchell acknowledged

5808-445: The absence of assisted migration programs. In their rejection of assisted migration, Ricciardi and Simberloff cite the precautionary principle, stating that any unknown risk, no matter how small, of assisted migration resulting in the creation of new invasive species is enough to require that it not be undertaken. Many scientists reject this position, however, noting that in many cases where extinctions due to climate change are likely,

5929-407: The agreement was at the level of "goals" and "targets," no mention was made of conservation tools, such as translocation, nor its climate-adaptive form (assisted migration). Although the Endangered Species Act of 1973 did not in itself restrict assisted migration, a regulatory change in 1984 regarding "experimental populations" made prospective translocations more difficult to justify. June 2022,

6050-399: The annual coral spawning is being experimented with to create hybrid offspring that will hopefully have higher survival and growth rates in a variety of climate change related conditions. In contrast, for neoendemic species , hybridization could result in a loss of biodiversity because closely related species that are offered a chance to interbreed could result in a single species rather than

6171-403: The availability of privately owned and commercially available plants and seeds." Four law review articles published between 2009 and 2017 concluded that the Endangered Species Act of 1973 (ESA) need not be amended to use assisted migration in species recovery. The citizen actions by Torreya Guardians in moving an endangered plant substantially northward of its native range remained an outlier to

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6292-563: The best science available—but requiring no taxpayer funds." Two forest owners asked for seeds as a result, including the owner of a 232 acre stewardship forest near the Cumberland Plateau (pictured at right). Meanwhile, academic scientists and working groups within the conservation community continued their deliberations to address the question of climate change adaptation , and to consider the scientific, legal, and ethical ramifications of assisted migration. This includes considering

6413-450: The case of some species, this can be accomplished with a captive breeding program A review paper published in the journal Science in 1989, titled "Translocation as a Species Conservation Tool: Status and Strategy," compiled the use of translocations for rare species (of birds and mammals) from 1973 to 1989 in the United States, Hawaii, Canada, Australia, and New Zealand. Habitat destruction , habitat fragmentation , and hunting were

6534-528: The chance that parental transmission of the gene in question occurs (also known as heritability ). Determining which genes within the genome produce desired behaviors or environmental tolerance consist of experiments which measure the growth, survival, and behavior exhibition of offspring with varying genotypes. AGF is one possible strategy to preserve species that are threatened by climate change, and can be applied to both plants (e.g. forest restoration ) or animal populations. Currently, different coral colonies of

6655-562: The citizen accomplishments in this regard. Glacial relict A glacial relict is a population of a species that was common in the Northern Hemisphere prior to the onset of glaciation in the late Tertiary that was forced by climate change to retreat into refugia when continental ice sheets advanced. They are typically cold-adapted species with a distribution restricted to regions and microhabitats that allow them to survive despite climatic changes. There are

6776-429: The citizen actions of Torreya Guardians as having preceded the official shift in willingness to consider northward experiments for other endangered species. Following the regulatory change, another journalist wrote that the "aggressive approach to conservation" by the Torreya Guardians "featured prominently in numerous scientific articles that followed, discussing the pros and cons of assisted migration." On their website,

6897-686: The climate is changing." Perhaps the principal concern scientists have expressed over assisted migration is the potential for relocated species to be invasive in their new habitats, driving out native species. The fear that assisted migration will facilitate invasions stems mostly from observations of the vast numbers of species that have become invasive outside their native ranges by (often inadvertent) introduction by humans. Although most agree that assisted migration efforts, unlike accidental introductions, should involve detailed planning and risk assessment, for some, any threat of introducing invasive species, no matter how small, disqualifies assisted migration as

7018-530: The climate will remain suitable long enough for colonizing species to mature and reproduce, if that is the management goal. Due to climate change, accidental species introductions, and other global changes, there is nowhere on the planet free of human disturbance. Thus, the idea that land managers should refrain from creating human-altered communities through assisted migration may be moot given that all communities have been altered by humans to some degree whether managers undertake assisted migration or not. Given

7139-647: The climate, humans may already be artificially segregating species even without actively relocating them. Critics may also have major concerns about different genetic issues when considering assisted migration such as maladaptation to novel environmental conditions and hybridization with similar species. These often depend on the genetic structure and level of genetic variation in the source populations. The environmental conditions in which these populations are being introduced must also be taken into account. In order to enhance genetic variation, and thus adaptive potential, material could be sourced from multiple populations. This

7260-829: The coming decades, as growing impacts from climate change and invasive species cause habitats within their historical ranges to shift and become unsuitable." The comment period ended August 2022, with more than 500 comments posted online by supporters and opponents. The final decision is scheduled for publication June 2023. A 2010 paper in Conservation Letters had pointed out that, while no statutory changes appeared necessary to facilitate this newly proposed form of climate adaptation, "current regulations are an impediment to assisted colonization for many endangered animal species, whereas regulations do not necessarily restrict assisted colonization of endangered plants." The U.S. Department of Interior in June 2023 announced its decision to modify

7381-402: The controversy entails more than the usual questions of whether, when, and how to apply assisted migration. The matter of who gets to make that decision is also central: Some would argue that it is unclear if this group [Torreya Guardians] should be labeled as "eco-vigilantes" or as "species saviors." However, what is clear is that if governments do not take swift and effective measures to save

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7502-464: The efforts of Torreya Guardians and others as being "relatively benign, so far." Yet he cautioned that the history of moving species to new areas had sometimes yielded "disastrous consequences." While management of an endangered plant or animal species is a central concern for conservation biologists, forestry researchers and managers focus on the overall health and resource potential of forest ecosystems—both in theory and in practice. The image (at right)

7623-490: The ever-growing list of endangered species, groups such as the Torreya Guardians will, in all likelihood, grow exponentially. This possibility is problematic because despite their good intentions, they are amateurs—they run the risk of doing more harm than good. If assisted relocations are to take place, they should be undertaken by well-trained professionals working under the auspices of governmental and academic organizations. Assisted migration In conservation biology ,

7744-541: The face of climate change varies by species and is generally poorly understood. One study determined that evolution of higher temperature tolerances in some species of amphibians and reptiles will likely occur fast enough to allow these species to survive a 3 °C temperature increase over 100 years, consistent with low- to mid-range projections of global warming. By contrast, many species, such as most temperate trees, have longer generation times and therefore may adapt more slowly; they may take thousands of years to evolve

7865-429: The fact that a given species may perform better (e.g., become invasive) or worse (e.g., fail to establish) in a new habitat than in its current range if the community of competitor , predator, and mutualist species is different there. Additionally, because different climate variables (e.g., minimum January temperature, average annual precipitation) rarely shift in unison, it is possible that few areas will exactly match

7986-475: The fitness of the hybrid species, there is a risk of extinction. This occurs when the population growth rate is below the replacement rate, wasting the reproductive potential of two populations. While assisted migration has the potential to allow species that have poor natural dispersal abilities to avoid extinction , it has also sparked debate over the possibility that the migrated species might spread diseases or even become too successful (that is, invasive ) in

8107-517: The focus of most of the early publications, animals took the lead in recent years. Corals, invertebrates, mammals, and birds were the leading types of animals assessed for assisted migration needs and prospects. Even so, "most authors presented assisted species migration as appropriate only for species under exceptionally high threat from climate change." By 2023, a news article in the journal Nature reported, "attitudes towards assisted migration are slowly shifting as conservationists realise just how fast

8228-416: The future, caused by the greenhouse effect, however, their range limit would need to move northward 100 km per °C warming.... Many species of trees may not be able to disperse rapidly enough to track climate, and woodland herbs, which have less efficient seed dispersal mechanisms, may be in danger of extinction." In 2020, the U.S. National Park Service began seriously considering how to adapt park ecologies to

8349-410: The genetics of an isolated population (American pika), to (b) preventing extinction of a subspecies (Quino checkerspot butterfly), to (c) preventing the extinction of a species (Florida torreya tree), and to (d) preventing extinction of a genus (Western swamp tortoise). The Florida torreya ( Torreya taxifolia) is a critically endangered tree of the yew family , Taxaceae , found in

8470-520: The green light for the relocation of a single species, the Western Larch , 1000 km northward. In the series below of actual and prospective assisted migration projects, all but one (Florida torreya tree) are being advocated and implemented by professional scientists, and usually with oversight by governmental endangered species programs. Taxonomic significance in successfully translocating plant and animal species range from (a) maintaining

8591-438: The group reported on its "Learnings" page that browsing by overpopulated deer was a bigger problem than harsh winters in northern states, such as Michigan, and that the Cleveland, Ohio, site produced more than a thousand seeds that year. The conservation community has expressed mixed feelings towards the volunteer-driven assisted migration project. When they started their endeavor, the assisted migration of trees in North America

8712-519: The group's emphasis not just in preventing extinction but also in re-integrating—that is, " rewilding "—this subcanopy species into native forest ecologies of the eastern United States. In subsequent years, seeds or potted seedlings were also given to planters in additional eastern states, and as far north as Wisconsin , Michigan , and New Hampshire . Several volunteer planters are trained (and sometimes employed) as professional ecologists or foresters, but most have acquired horticultural skills outside of

8833-594: The growing importance of this controversy in light of ongoing climate change. There, lead author Jedediah Brody summed up the concern in his field of conservation biology this way: "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." Speaking for the team, Brodie said that the international community needed "a clear and coherent framework" by which assisted colonization projects can be "evaluated, vetted, regulated and reported." In this regard, Brodie characterized

8954-443: The historical climates of species threatened by climate change. Such multi-directional climate shifts will make it especially difficult to determine the species that are at greatest risk of habitat loss due to climate change and to predict future suitable habitat. The uncertainties in predictions of future suitable habitat limits confidence in assisted migration decisions and has led some to reject assisted migration entirely. Despite

9075-576: The horticultural trade, has also been documented for plants in the United States. In the North American context, assisted migration is most often discussed in the context of the relocalization of the continent's forests . In the late 2000s and early 2010s, the Canadian provinces of Alberta and British Columbia modified their tree reseeding guidelines to account for the northward movement of forest's optimal ranges. British Columbia even gave

9196-406: The immediate threats of predation, disease, and habitat loss can be avoided. However, these species are usually already suffering from some sort of genetic issue resulting from low effective population size such as inbreeding depression, loss in genetic diversity, or maladaptation. Therefore, caution must be taken with what few individuals remain and rapid population growth must be the primary goal. In

9317-416: The new high elevation expansion, will become uninhabitable. Our most frequent projected future range (circa 2050) is c. 400 km northward from current populations, hence conservation of Quino may eventually require assisted colonization." Within the first decade of the terms assisted migration and assisted colonization appearing in the journals of conservation biology science, two wide-ranging species in

9438-426: The official endangered species policies until June 2023. It was then that regulations governing the parameters of recovery plans were amended "to reduce the impacts of climate change and other threats such as invasive species." Deletion of "historical range" as a location parameter for "experimental populations" effectively authorized assisted migration for listed species. A press report on the regulatory change mentioned

9559-518: The organization's Conservation Translocation Specialist Group; but "assisted colonization" as an adaptive response was mentioned just once. In 2022, the update of the United Nations Convention on Biological Diversity agreement recognized "climate change" as the third most significant threat to global biodiversity. "Changes in land and sea use" along with "direct exploitation of organisms" were regarded as greater threats. Because

9680-447: The original two or more. Cupressus abramsiana is such an example. The 2016 federal update of the recovery plan for this threatened cypress tree, endemic to a small geographic region along the California coast, warned of the dangers of hybridization. A section of the plan titled "Genetic introgression" (also known as introgressive hybridization ) explains how the integrity of this species is threatened by nearby horticultural plantings of

9801-536: The past several decades of global warming . This is especially the case in the United Kingdom , where natural history observations are reputable and reach back several centuries. It has also been documented that plants are being sold in nurseries in Europe far north of their historically native ranges, and with apparent success in the colder habitats. Evidence of such "inadvertent assisted migration", owing to

9922-472: The potential harm of any project. Detractors generally believe that other conservation techniques which do not include the high risk of invasive species are not only better suited but are also more likely to succeed. This debate continued throughout the literature, generally due to a lack of real-world applications and follow-ups. Though these conservation efforts are becoming increasingly common, few long term looks at their success have been conducted. In 2022

10043-489: The practice of using human intervention to accelerate the rate of natural evolutionary processes. There are three main types of assisted evolution. Stress conditioning consists of exposing organisms to sublethal stress, with the goal of inducing physiological changes that increase tolerance to future stress events. There has been documented evidence that some changes can be passed throughout generations in both plants and animals. Stress conditioning can be artificially induced in

10164-515: The presence of desired naturally-occurring genes in offspring . AGF relies on pre-existing genes within the species' genome , rather than the artificial creation and insertion of genetic code within the genome of the species. Assisted gene flow can also introduce related species' genomes into the gene pool to allow for the introduction of previously impossible behaviors into the new species. AGF identifies genes that produce desired behaviors or tolerance to environmental conditions, and works to increase

10285-469: The preservation of the Florida torreya within its native range since 1988, wrote the piece opposing the assisted migration proposal. He was particularly worried about the precedent that citizen-led assisted migration of the endangered tree would set, the risk that even an endangered plant might become invasive in a different ecosystem, and the possibility of spreading the diseases afflicting the tree in Florida. These concerns were shared by Jenny Cruse-Sanders of

10406-609: The primary causes of decline listed in that paper. Climate change was not mentioned as a cause for concern. Three decades later, the International Union for the Conservation of Nature (IUCN) published that "climate change currently affects at least 10,967 species on the IUCN Red List of Threatened Species." In another IUCN publication in 2021, climate change was mentioned 20 times in a 355-page report by

10527-399: The probable distances of future range shifts prompted attention. As well, translocation terminology was not controversial among forestry researchers because migration was the standard term used in paleoecology for natural movements of tree species recorded in the geological record . Another key difference between forestry practices and conservation biology is that the former, necessarily,

10648-445: The pros and cons of assisted migration as a climate-adaptation tool for endangered species conservation often mentioned the Florida torreya project., as did international media The western swamp tortoise ( Pseudemydura umbrina ) is a critically endangered reptile that is endemic to a small portion of southwestern Australia . It was deemed extinct until it was rediscovered in 1954 and reported in 1981 to be "a relict species of

10769-434: The ramification of risking species going extinct because humans did not relocate them to a climate where they could thrive. Overall, a growing number of scholars conclude that the risk of spreading invasive species is small when native plants are moved poleward—and that it may be a risk worth taking. For ecologist Richard Primack, having endangered species go extinct would be a worse tragedy. "These endangered species have such

10890-454: The range of coast redwood. As to Florida torreya, documentation of "historic groves in northward states" was presented by the group Torreya Guardians as a supportive factor in their 2019 "Petition to Downlist from endangered to threatened Torreya taxifolia ". Two years later, a decision was issued and published, with no change in species status of imperilment. But Factor E of the decision, "Documentation of Historical Groves," did acknowledge

11011-607: The reality of global change, it will be impossible to maintain past ecological communities indefinitely. Many therefore believe we should strive to maintain biodiversity and functioning ecosystems in the face of climate change, even if it means actively moving species beyond their native ranges. In the absence of assisted migration, climate change is already causing many highly mobile species, such as butterflies, to colonize areas they have not previously inhabited. Through assisted migration, managers could help rare or less-mobile species keep pace, possibly preventing future extinctions due to

11132-489: The recipient ecosystems. Even so, several assisted migration projects or experiments have begun for several critically endangered species . Beginning around 2007, opposing pro and con positions became apparent in the field of conservation biology, while still relatively unknown to public promoters of conservation and managers of conservation lands. Supporters generally believe that the expected benefits of assisted migration, including saving and strengthening species, outweigh

11253-591: The release of 24 captive-raised juveniles. In contrast to the Florida torreya tree example, this first experiment in assisted migration of an endangered species in Australia was "preceded by detailed planning and research." A generally positive result, despite impediments to statistically significant data, was reported in a journal article four years later. A second trial began in 2022 in the same region, this time in Scott National Park . Lead scientist

11374-460: The risks of extinction from not facilitating migration are probably far worse than the risks of facilitating migration. They argue that the precautionary principle cuts both ways, and the risks of inaction must be compared against the risks of action. Others note that the ethics of assisting migration will depend on the values of the stakeholders involved in a specific decision rather than the position of scientists on assisted migration in general. At

11495-461: The risks, while offering "we can potentially undo our mistakes by recapturing them." Additional translocations of baby turtles continued into 2023. The Quino checkerspot ( Euphydryas editha quino ) is a butterfly native to southern California and northwestern Baja California . It is a subspecies of the common Edith's checkerspot ( Euphydryas editha ), which ranges as far north as southern British Columbia and Alberta . In 1997 it became

11616-617: The same continent where the species originated. Of the 14.7%, the vast majority were fish and crustaceans. Terrestrial species that became invasive on the same continent where they originated were often transported across large biogeographic barriers, such as mountain ranges. These long-distance, within-continent translocations are unlike expected uses of assisted migration, which generally involve helping species colonize habitats immediately adjacent to their current ranges. To identify populations at risk and locate new potential habitats, conservationists often use niche models . These models predict

11737-843: The second subspecies of Edith's checkerspot to be listed under the federal Endangered Species Act . (The first was Bay checkerspot, which was listed as "threatened" in 1987.) Notably, it became the first endangered species for which climate change was reported as a current threat and thus a factor to be considered in its recovery plan. However, as reported in The Guardian April 2014 A butterfly species whose population collapsed because of climate change and habitat loss has defied predictions of extinction to rapidly move to cooler climes and change its food plant. The quino checkerspot ( Euphydryas editha quino ), found in Mexico and California, has shifted to higher altitudes and surprisingly chosen

11858-445: The section 10(j) rule by deleting reference to "historical range" as a parameter for where "experimental populations" were authorized to be located. This effectively authorized assisted species migration for endangered or threatened plants and animals. The press release summarized the reason for the change as, "At the time the original 10(j) regulations were established, the potential impact of climate change on species and their habitats

11979-456: The seeds of the critically endangered conifer Torreya taxifolia hundreds of miles north of its Florida home." Professionals in conservation biology have criticized the actions of Torreya Guardians since their inception. Mark Schwartz, who wrote the 2004 Wild Earth article opposing the group's proposed assisted migration project, reiterated his critique as lead author or coauthor of professional papers published in 2007, 2009, and 2012. Schwartz

12100-466: The sites it did not colonize were located far from existing populations, suggesting they were uncolonized because the butterfly could not reach them on its own. The data suggested that the suitable, uncolonized sites could be good targets for assisted migration. The results suggested that if investigators can demonstrate their model makes reliable predictions with real-world data, models might be trusted for informing assisted migration decisions. The science

12221-688: The southeastern United States, umbrella magnolia , that had fully naturalized into a forest adjacent to its original horticultural planting in Massachusetts was the subject of an earlier paper by Bellemare. This and other examples suggest not only that poleward assisted migration of plants can be successful, but that distinguishing native from non-native species in this time of rapid climate change will require novel standards. Reports of full naturalization of poleward horticultural plantings of other native trees have been used as support for intentional deployment of assisted migration at larger scales as

12342-488: The species as critically endangered since 1998. It is considered "the rarest conifer in North America." In 2010 98% of the mature trees of the species were believed to have been destroyed due to a poorly understood fungal blight as well as inundation due to dams and destruction by deer using trees as antler rubbing posts. In 2019 a staff biologist for the park in northern Florida named for this tree, Torreya State Park , spoke of this species as being "functionally extinct in

12463-764: The species would be able to disperse fast enough via natural selection to keep pace with the changing environment. Assisted migration practitioners consider helping the species disperse into such sites, which are often immediately adjacent to the species’ historical range. In their eyes, assisted migration represents a small artificial boost to an otherwise natural process. Even under rapid climate change, dispersal into new areas may not be necessary for some species to persist. Instead of tracking climate shifts through space, some species may be able to survive in their present locations by developing tolerance to new conditions through acclimatization and adaptation . The potential for acclimatization or adaptation to allow persistence in

12584-471: The states of North Carolina , Tennessee , and Ohio . Before their formation, they were searching for ways to better protect Torreya taxifolia from extinction. They worried that traditional conservation measures focused on rehabilitating the tree in its historical range were destined to fail, as well as being very expensive. Then, early members learned by visiting Torreya californica in forested sites in California, and through reports, that other trees of

12705-469: The suitability of habitats in the future based on how closely their climates resemble the climate currently inhabited by the species. Though useful for describing broad trends, these models make a number of unrealistic assumptions that restrict the usefulness of their predictions. For instance, they do not consider the possibility that species may be able to develop tolerance of new climates through acclimatization or adaptation. Further, they do not account for

12826-422: The term first appeared in publications in 2004. It signified a type of species translocation intended to reduce biodiversity losses owing to climate change . In the context of endangered species management, assisted colonization (2007) and managed relocation (2009) were soon offered as synonyms — the latter in a paper entailing 22 coauthors. In forestry science and management, assisted migration

12947-611: The traditional methods of conservation. The Torreya Guardians had proved that assisted migration of an endangered plant could be done without sophisticated conservation techniques and for little cost. In 2015 the Tennessee chapter of the Sierra Club published an article in its autumn newsletter, written by a Torreya Guardian, in which new planters in that state were sought for a citizen science project demonstrating "how citizens can actively engage in forestry climate action, using

13068-463: The uncertainty inherent in predictions of future suitable habitat, some studies have demonstrated that predictions can be quite accurate. A study of Hesperia comma butterflies in Britain identified unoccupied habitat sites that were likely to support the species under a warmer climate based on their similarity to occupied sites. As the climate warmed, the butterfly colonized many of the sites; most of

13189-428: The very least, some note, scientists should conduct further research into assisted migration and improve our capacity to predict specific outcomes instead of outright rejecting it. Because confidence in expected outcomes is often greater in the short-term (e.g., 20 years) than the long-term future, it may be more reasonable to use short-term projections to guide actions. However, it is also important to consider whether

13310-788: The western USA (image right) were scrutinized for possible application of the new climate adaptation tool. The American pika , Ochotona princeps , (a close relative of rabbits) and the Joshua tree , Yucca brevifolia , (the iconic tree of the Mojave Desert ) were experiencing climate-driven range contractions in their southernmost populations. At the time, when climate-adaptation tools were originally discussed, scientific applications to well-known species garnered media attention. Because successfully capturing, transporting, and releasing an alpine mammal would require planning and "considerable financial resources," serious advocacy for launching such

13431-429: The wild. As those cuttings turned into shrubs, they were transferred into large pots or moved into managed horticultural plantings for genetic safeguarding until problems in the habitat itself could be discerned and corrected. Connie Barlow, on the other hand, believed that it made little sense to focus on finding a way to return torreya to its endemic habitat during a time of climate warming. Pointing to torreya's status as

13552-513: The wild." Climate change is increasing the average temperatures of American forests. Forests in the contiguous United States have experienced a 0.8 °C increase since 1900. That some native trees already lag in northward range expansion was known in the 20th Century, and has increased during 21st Century warming. A classic paper by forestry scientist Margaret B. Davis was published in 1989 and titled, "Lags in vegetation response to greenhouse warming." She concluded, "To track climatic changes in

13673-653: The world. Prehistoric climatic changes have resulted in massive global extinctions, and the rate of warming projected for the near future is many times faster than changes in the past 10,000 years. Geographic or human-caused barriers to natural dispersal may already be at cause for the listing as "critically endangered" two small-range endemic species for which assisted migration is now underway: Australia's western swamp tortoise and America's Florida torreya tree. The inability of species to migrate in response to human-caused climate change has led to some scientists and land managers to consider exploring assisted migration as

13794-423: Was also a coauthor of two papers published in 2021 that expressed continuing caution about translocating animal and plant species for climate adaptation purposes—with unfavorable effects on "recipient ecosystems" being one of the primary risks to consider. When speaking to a journalist about these papers, Schwartz referred to the endeavors of Torreya Guardians as "misguided." Conservation biologist Daniel Simberloff

13915-407: Was among the first to strongly criticize assisted migration as a climate adaptation tool in general, and the actions of Torreya Guardians in particular: "They've just decided on their own to move trees with no consideration, no oversight, by anyone with expertise in tree biology," Simberloff said. "That is a terrible precedent to set." The group's actions did stimulate many conservationists to rethink

14036-408: Was considered a "radical conservation idea". The Torreya Guardians have been called a "rogue" group for not following the guidelines of the International Union for Conservation of Nature . And yet, a 2017 editorial within a leading international journal, Nature , characterized the group's actions in this way, "In one of the only real-world examples of assisted migration so far, campaigners have planted

14157-717: Was created in 2014 by research staff of the U.S. Forest Service , Mary I Williams and R Kasten Dumroese. Their report to the agency, along with a journal article they published in 2013 served to defuse controversy about assisted migration in the field of forestry . The most detailed case study of Torreya Guardians published in a science journal was written by a pair of Canadian Forest Service researchers and published in The Forestry Chronicle . Table 2 of that 2011 report lists six "Ecological standards for assisted migration developed for Torreya taxifolia ". They conclude, "The momentum that this group has created resulted in

14278-520: Was guided by "seed transfer guidelines" whenever a timber or pulp harvest was followed up by reforestation plantings. The provincial government of British Columbia in Canada was the first to update their guidelines with, what they call, "climate-based seed transfer." Overall, debate concerning the ethics of assisted migration in forestry practice was both short-term and muted compared to that which prevails in conservation biology. For this reason,

14399-570: Was motivated by the endangered status of Florida Torreya and by their view that the species belongs to the Appalachian Mountains as it is thought to have lived there before (Torreya Guardians 2014). As these examples show, naturalness as belonging leaves room for different kinds of interpretations of the relation of ‘belonging’. The author of a 2020 article published in the journal Ethics and Environment also chose Florida torreya for ethical analysis of assisted migration. In this case,

14520-556: Was not fully realized, yet in the decades since have become even more dramatic. 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." A number of scholarly reports have documented natural poleward range shifts of mobile species — notably, butterflies and birds, during

14641-401: Was studied in the 1800s by Johann Gregor Mendel , who posthumously has been credited with the discovery of genes and alleles and their impact on an offspring's genotype. Benefits of hybridization include the increase in genetic diversity and the potential for genetic combinations which are able to adapt to, and reproduce in, increasingly difficult environments. Hybridization of coral reefs during

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