Recovery Units under the Endangered Species Act could be used more widely

Abstract Recovering species is one of the main goals of the Endangered Species Act (ESA). In the face of limited budgets, diverse tools are needed to find efficient solutions. Recovery units may be one such tool - designated portions of a species’ range that must be recovered individually before an entire species can be considered recovered. Recovery units allow for spatial flexibility in recovery goals and may be used in regulatory decisions such as section 7 consultation. Despite their availability, there is very little information on how recovery units have been developed and used. We mined available public data to determine the number and types of species for which recovery units have been designated; evaluated species and geographic characteristics associated with recovery unit designation; and examined how recovery units have been used in the implementation of the ESA, such as during consultation. We found 49 listed species have designated recovery units through 2017, and that these species had similar characteristics. Namely, they had relatively large ranges and were well-studied. We found taxonomic biases in recovery unit designation as well, with fish species being disproportionately likely to have recovery units and plants disproportionately less. Improvements in recovery priority numbers among species with recovery units indicate that the theoretical benefits of this tool may have translated to improved status. These data indicate that recovery units could be applied to more wide-ranging species to improve recovery under the ESA.