Distinct population segments and grizzly bear delisting in Yellowstone: a response to Rosen

Abstract

Tatjana Rosen (previous article) recommends reforms to the policy outlining how distinct population segments (DPSs) are defined and then objects because the proposed DPS for delisting grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE) does not mesh with her recommendations. The purpose of the Endangered Species Act (ESA; 16 US Code 1531–1544) is to prevent the extinction of species, subspecies, and distinct population segments (DPSs) of imperiled plants and animals, not to keep species perpetually listed. Policies designed to implement the ESA should be judged based on their contribution to the recovery of taxa and DPSs. In response to management efforts by state and federal agencies assisted by conservation groups, grizzly bears in the GYE have expanded in range and numbers and have exceeded recovery criteria established in the Recovery Plan. Although the current DPS policy may not be the perfect tool for listing or delisting in all circumstances, the DPS proposed for delisting Yellowstone's grizzlies meshes well with the intent of the ESA. Rosen's suggested revisions would lead to perpetual listing in areas where recovery has occurred and would be inconsistent with the purpose of the ESA to delist taxa and DPSs following recovery. In the GYE, and elsewhere south of Canada, grizzly bears will probably always remain a conservation-reliant species; this does not mean that they require or will benefit from continued listing when conservation efforts have succeeded in reaching recovery targets and regulatory mechanisms are in place to nurture the recovery.