Subpopulation triage: How to allocate conservation effort among populations

McDonald-Madden, E., Baxter, P.W.J. and Possingham, H. (2008) Subpopulation triage: How to allocate conservation effort among populations. Conservation Biology, 22 3: 656-665. doi:10.1111/j.1523-1739.2008.00918.x

Author McDonald-Madden, E.
Baxter, P.W.J.
Possingham, H.
Title Subpopulation triage: How to allocate conservation effort among populations
Journal name Conservation Biology   Check publisher's open access policy
ISSN 0888-8892
Publication date 2008-06
Sub-type Article (original research)
DOI 10.1111/j.1523-1739.2008.00918.x
Volume 22
Issue 3
Start page 656
End page 665
Total pages 10
Place of publication Malden, MA, U.S.A.
Publisher Blackwell
Collection year 2009
Language eng
Subject C1
960899 Flora, Fauna and Biodiversity of Environments not elsewhere classified
050202 Conservation and Biodiversity
Abstract Threatened species often exist in a small number of isolated subpopulations. Given limitations on conservation spending, managers must choose from strategies that range from managing just one subpopulation and risking all other subpopulations to managing all subpopulations equally and poorly, thereby risking the loss of all subpopulations. We took an economic approach to this problem in an effort to discover a simple rule of thumb for optimally allocating conservation effort among subpopulations. This rule was derived by maximizing the expected number of extant subpopulations remaining given n subpopulations are actually managed. We also derived a spatiotemporally optimized strategy through stochastic dynamic programming. The rule of thumb suggested that more subpopulations should be managed if the budget increases or if the cost of reducing local extinction probabilities decreases. The rule performed well against the exact optimal strategy that was the result of the stochastic dynamic program and much better than other simple strategies (e.g., always manage one extant subpopulation or half of the remaining subpopulation). We applied our approach to the allocation of funds in 2 contrasting case studies: reduction of poaching of Sumatran tigers (Panthera tigris sumatrae) and habitat acquisition for San Joaquin kit foxes (Vulpes macrotis mutica). For our estimated annual budget for Sumatran tiger management, the mean time to extinction was about 32 years. For our estimated annual management budget for kit foxes in the San Joaquin Valley, the mean time to extinction was approximately 24 years. Our framework allows managers to deal with the important question of how to allocate scarce conservation resources among subpopulations of any threatened species.
Keyword Decision theory
Financial resource allocation
Optimal management
Rule of thumb
Stochastic dynamic programming
Sumatran tiger
San Joaquin kit fox
Threatened species
Q-Index Code C1
Q-Index Status Confirmed Code

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