Assisted migration is the practice of deliberately populating members of a species from their present habitat to a new region with the intent of establishing a permanent presence there, generally in response to the degradation of the natural habitat due to human action. The human action most frequently considered is climate change, but assisted migration can be in response to habitat loss or other impacts to historic range.

Assisted migration flies in the face of conventional management approaches that attempt to (re)establish habitat corridors that allow species to disperse in response to a changing climate. There is good reason to be skeptical of this conservation strategy given that history has shown that species introduced outside of their native range can be associated with negative ecological, evolutionary, and economic impacts (Ricciardi and Simberloff 2009). However, it is important not to dismiss this approach given the rapidity by which habitat and climate is changing, and the simple fact that species may not be able to keep pace (i.e., dispersal to favorable climates in the future).

In 2007 conservation biologists began formally discussing assisted migration as a mechanism for dealing with the predicted effects of global warming on biological species.^[1]

In July 2008, the first clear instance of intentional assisted migration in behalf of an endangered tree was undertaken by citizen activists in the United States. The Florida species of genus Torreya was restored to range considered by the activists to have been "native" range for the tree prior to the most recent advance of glacial ice: western North Carolina.^[2]

Although assisted migration has only recently come to the forefront of environmental debate, the idea of humans assisting in the forced migration of certain species to more suitable habitats is not a new phenomenon. In 1847 Charles Darwin wrote the governor of Mauritius warning that the giant tortoises of the Aldabra islands would face extinction if they were not moved to a new area to repopulate.^[3] The governor took his advice and today the tortoises' "descendants can be found on islands across the Indian Ocean."^[4]

See also

• Acclimatisation society
• Introduced species
• Pleistocene rewilding

Notes

1. ↑ A Radical Step to Preserve a Species: Assisted Migration, Carl Zimmer, New York Times. January 23, 2007.
2. ↑ Rewilding of Torreya taxifolia to Previous Interglacial Range, Torreya Guardians. August 2, 2008.
3. ↑ http://www.wired.com/wiredscience/2012/02/assisted-migration/?pid=3011
4. ↑ http://www.wired.com/wiredscience/2012/02/assisted-migration/?pid=3011

Further reading

Biello, David. 2008. Deporting plants and animals to protect them from climate change. Scientific American 7-17-2008.

Fox, Douglas. 2007. When worlds collide. Conservation 8(1):28-34.

McLachlan, J. S., J. J. Hellmann, and M. W. Schwartz. 2007. A framework for debate of assisted migration in an era of climate change. Conservation Biology 21: 297-302

Nijhuis, Michelle. 2008. Taking Wildness in Hand: Rescuing Species. Orion Magazine May/June 2008, pp. 64-78.

Ricciardi, A. and D. Simberloff. 2009. Assisted colonization is not a viable conservation strategy. Trends in Ecology and Evolution. 24: 248-253.

Shirey, P.D. and G.A. Lamberti. 2010. Assisted colonization under the U.S. Endangered Species Act. Conservation Letters 3(1):45-52.

Shirey, P.D. and G.A. Lamberti. 2011. Regulate trade in rare plants. Nature 469: 465-467.

Torreya Guardians has a webpage devoted to hotlinks for following the proposals and news on assisted migration, assisted colonization, and Pleistocene Rewilding: "Assisted Migration Hotlinks".

Assisted Migration Working Group. http://assistedmigration.wiki.zoho.com/Managed-relocation.html.

Camacho, A., Assisted Migration: Redefining Nature and Natural Resource Law Under Climate Change, Yale Journal on Regulation, Vol. 27, p. 171, 2010 (http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1495370).