Protocols for listing threatened species can forecast extinction |
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| Authors: | David A Keith Michael A McCarthy Helen Regan Tracey Regan Christy Bowles Claire Drill Corey Craig Belinda Pellow Mark A Burgman Larry L Master Mary Ruckelshaus Berin Mackenzie Sandy J Andelman Paul R Wade |
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| Institution: | New South Wales National Parks and Wildlife Service, Hurstville, NSW 2220, Australia; School of Botany, University of Melbourne, Parkville, Vic. 3010, Australia; Australian Research Centre for Urban Ecology, Royal Botanic Gardens Melbourne, Birdwood Avenue, South Yarra, Vic. 3141, Australia; Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92181-4614, USA; The Ecology Centre, Life Sciences, University of Queensland, St Lucia, Qld 4072, Australia; National Center for Ecological Analysis and Synthesis, University of California, Santa Barbara, CA 93101, USA; Physical Science and Engineering Library, One Shields Avenue, University of California, Davis, CA 95616-8676, USA; Janet Cosh Herbarium, School of Biological Sciences, University of Wollongong, Wollongong, NSW 2253, Australia; NatureServe, 11 Avenue de Lafayette, 5th Floor, Boston, MA 02111, USA; Northwest Fisheries Science Center, National Marine Fisheries Service, 2725 Montlake Boulevard East, Seattle, WA 98112, USA; National Marine Mammal Laboratory, Alaska Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115, USA |
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| Abstract: | Risk‐ranking protocols are used widely to classify the conservation status of the world's species. Here we report on the first empirical assessment of their reliability by using a retrospective study of 18 pairs of bird and mammal species (one species extinct and the other extant) with eight different assessors. The performance of individual assessors varied substantially, but performance was improved by incorporating uncertainty in parameter estimates and consensus among the assessors. When this was done, the ranks from the protocols were consistent with the extinction outcome in 70–80% of pairs and there were mismatches in only 10–20% of cases. This performance was similar to the subjective judgements of the assessors after they had estimated the range and population parameters required by the protocols, and better than any single parameter. When used to inform subjective judgement, the protocols therefore offer a means of reducing unpredictable biases that may be associated with expert input and have the advantage of making the logic behind assessments explicit. We conclude that the protocols are useful for forecasting extinctions, although they are prone to some errors that have implications for conservation. Some level of error is to be expected, however, given the influence of chance on extinction. The performance of risk assessment protocols may be improved by providing training in the application of the protocols, incorporating uncertainty in parameter estimates and using consensus among multiple assessors, including some who are experts in the application of the protocols. Continued testing and refinement of the protocols may help to provide better absolute estimates of risk, particularly by re‐evaluating how the protocols accommodate missing data. |
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| Keywords: | Conservation decisions extinct species IUCN Red List missing data model testing NatureServe operator error risk assessment threatened species lists uncertainty |
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