Endangered Species Recovery Criteria: Reconciling Conflicting Views

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Recovery criteria (RC) serve the important purpose of determining when an endangered species can be delisted, or removed from protection under the Endangered Species Act (ESA). Although delisting is the ultimate goal for recovering all threatened species, it has been a controversial process, because delisted species may lose some protection provided by the ESA, making them susceptible to the same causes of decline that resulted in their initial listing. RC are designated by the US Fish and Wildlife Service (USFWS) in the recovery plan of an endangered species, and the ESA mandates that RC should be based on “objective, measurable criteria.” How to designate RC has been a thorny problem since the ESA was enacted in 1972. In this issue of BioScience, we find conflicting views of how RC should be determined offered by Doak and colleagues and by Wolf and colleagues. The authors of both articles champion the application of quantitative RC in place of the heterogeneous approach currently used. But here the similarities end. Doak and colleagues argue that RC should be based on “demographic criteria,” emphasizing estimates of the risk of extinction from a population viability analysis (PVA) that projects population size for decades to 100 years (or more) into the future. Under this approach, recovery plans would be required to include RC tied to the probability of meeting specific extinction risk or demographic thresholds from models. In contrast, Wolf and colleagues espouse a less data-intensive and broader set of methods, based on the ecological principles of representation, resiliency, and redundancy (the “3Rs”). The 3Rs would be evaluated quantitatively or qualitatively using multiple approaches for setting recovery targets, such as the percentage of historic range, population size, the number and spatial distribution of populations, and the risk of extinction from a PVA when adequate data are available. Both articles provide important insights into the shortcomings of past efforts to delineate RC and discussion of the concepts for delineating RC. But both run head on into the same knotty problems of developing quantitative criteria for RC that relate to population viability and the absence of risk standards.