The use of surrogates in implementation of the federal Endangered Species Act—proposed fixes to a proposed rule

The US Fish and Wildlife Service and National Marine Fisheries Service recently proposed to amend existing regulations that implement the Endangered Species Act’s interagency consultation process by codifying their pre-existing practice of using surrogates to express the amount or extent of incidental take of listed species. The agencies contend that amendments both are necessary as a practical matter and are defensible on ecological grounds. They propose the use of surrogates, either in the form of a substitute species filling in for a species that is challenging to observe or measure, or a land-cover type or another habitat attribute, as proxies for the amount or extent of anticipated take. We contend that the proposed rule leaves the process of surrogate selection and application without essential implementation details and describe five essential steps in surrogate selection and validation. In sum, an obligatory validation procedure should clearly articulate the reasoning behind the selection of the surrogate, including describing the similarities in responses by the surrogate and target species to the same environmental phenomena, linking demographic responses to habitat extent and condition, and describing the uncertainties that accompany the relationship between the status and trends of the surrogate and those of the target species or its habitat under common circumstances. Copyright The Author(s) 2014