Assisted Colonization: Move Ahead with Models

Abstract

Moving species outside their natural ranges has long been recognized as risky (“Home, home outside the range?”, R. Stone, News Focus, 24 September, p. [1592][1]). Current accepted procedure allows for translocations outside the historic range only reactively—when there is no suitable habitat left in that range ([ 1 ][2]). For example, flightless birds such as kakapo and takahe have been introduced to offshore islands because exotic mammalian predators had rendered them unable to persist on the New Zealand mainland. Soon, we may have to move species proactively as a means to save them from anticipated shifts in habitat due to climate change. Proactive assisted colonization is understandably contentious. The best way forward involves careful modeling and collaboration. There are many cautionary experiences from invasive species and biological control releases ([ 2 ][3]). However, tools such as structured decision-making enable us to make decisions in the face of uncertainty about ecological roles and relationships that we will have least cause to regret. We can construct models around the fate of species if we leave them to face climate change either by adapting, by moving, or by dying out. We can explore a deliberately moved species' prospects of (i) dying out at its human-selected destination, (ii) establishing and becoming a pest, or (iii) settling down within desired population limits. The test case in the News story of the two butterflies in the United Kingdom ([ 3 ][4]) is an example of the low-risk and potentially reversible type of experiment that we should be starting now. With assisted migration recognized as one means to reduce the impacts of climate change on biodiversity ([ 4 ][5]), we need international guidelines on the conditions under which it may be an acceptable solution. Consequently, the IUCN Species Survival Commission has established a task force from within its Re-introduction and Invasive Species Specialist Groups to review and update its 1998 guidelines to explicitly accommodate these issues surrounding assisted colonization. The task force will report to the World Conservation Congress in 2012. 1. [↵][6]IUCN/SSC Re-introduction Specialist Group, “Guidelines for re-introductions” (IUCN, Gland, Switzerland, 1998). 2. [↵][7]1. A. Ricciardi, 2. D. Simberloff , Trends Ecol. Evol. 24, 248 (2009). [OpenUrl][8][CrossRef][9][PubMed][10][Web of Science][11] 3. [↵][12]1. S. G. Willis 2. et al ., Conserv. Lett. 2, 45 (2009). [OpenUrl][13] 4. [↵][14]CBD, Conference of the Parties, “Biodiversity and climate change” (UNEP/CBD/COP/10/L.36, 2010). [1]: pending:yes [2]: #ref-1 [3]: #ref-2 [4]: #ref-3 [5]: #ref-4 [6]: #xref-ref-1-1 View reference 1 in text [7]: #xref-ref-2-1 View reference 2 in text [8]: {openurl}?query=rft.jtitle%253DTrends%2Bin%2BEcology%2B%2526%2BEvolution%26rft.stitle%253DTrends%2Bin%2BEcology%2B%2526%2BEvolution%26rft.aulast%253DRicciardi%26rft.auinit1%253DA.%26rft.volume%253D24%26rft.issue%253D5%26rft.spage%253D248%26rft.epage%253D253%26rft.atitle%253DAssisted%2Bcolonization%2Bis%2Bnot%2Ba%2Bviable%2Bconservation%2Bstrategy.%26rft_id%253Dinfo%253Adoi%252F10.1016%252Fj.tree.2008.12.006%26rft_id%253Dinfo%253Apmid%252F19324453%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [9]: /lookup/external-ref?access_num=10.1016/j.tree.2008.12.006&link_type=DOI [10]: /lookup/external-ref?access_num=19324453&link_type=MED&atom=%2Fsci%2F330%2F6009%2F1317.1.atom [11]: /lookup/external-ref?access_num=000266188100005&link_type=ISI [12]: #xref-ref-3-1 View reference 3 in text [13]: {openurl}?query=rft.jtitle%253DConserv.%2BLett.%26rft.volume%253D2%26rft.spage%253D45%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [14]: #xref-ref-4-1 View reference 4 in text