Assisted migration

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.

[7][8][9][10] In the 1990s, forestry researchers had begun applying climate change projections to their own tree species distribution modelling efforts, and some results on the probable distances of future range shifts prompted attention.

Another key difference between forestry practices and conservation biology is that the former, necessarily, was guided by "seed transfer guidelines" whenever a timber or pulp harvest was followed up by reforestation plantings.

[17][18][15][16] For this reason, a separate Wikipedia 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.

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.

[26] 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[27] and America's Florida torreya tree.

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.

[52] Through assisted migration, managers could help rare or less-mobile species keep pace, possibly preventing future extinctions due to a their inability to colonize new areas fast enough.

[54] 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.

[57] 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 a similar increase in temperature tolerance.

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.

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.

[66] 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.

"[71] The U.S. Department of Interior in June 2023 announced its decision to modify the section 10(j) rule by deleting reference to "historical range" as a parameter for where "experimental populations" were authorized to be located.

"[73] A number of scholarly reports have documented natural poleward range shifts of mobile species — notably, butterflies and birds, during the past several decades of global warming.

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.

[78] 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.

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.

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.

"[89] 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.

", 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.

[99] Because successfully capturing, transporting, and releasing an alpine mammal would require planning and "considerable financial resources,"[98] serious advocacy for launching such a project for the pika did not occur.

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, the Joshua Tree.

[104][105] Thirteen scientists coauthored a paper titled, "Establishing monarch butterfly overwintering sites for future climates: Abies religiosa upper altitudinal limit expansion by assisted migration."

They wrote, "We conclude that the establishment of A. religiosa at 3,600 and 3,800 meters is feasible and that planted stands could eventually serve as overwintering sites for the Monarch butterfly under projected future climates.

"[106] Establishing a slow-growing tree to serve as a mature forest sanctuary by century's end for a migratory insect is a second-level complication beyond the single-species projects that are still considered controversial.

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.

"[76] A subcanopy tree native to 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.

[110] 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.

[111] 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 a tool for climate adaptation.