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Significant Portion of Its Range

The U.S. Fish and Wildlife Service and NOAA Fisheries Service (Services) jointly announce a policy to improve and clarify implementation of the Endangered Species Act (ESA) by providing a formal interpretation of the phrase "significant portion of its range" that appears in the ESA definitions of "endangered species" and "threatened species." This policy improves ESA implementation by providing a consistent and uniform standard for interpretation of the phrase "significant portion of its range" by the Services in making decisions to list species in need of federal protection and delist species no longer in need of federal protection.

Karner blue butterfly.

This policy clarifies that the Services can list a species if it is endangered or threatened in a "significant portion of its range," even if that species is not endangered or threatened throughout all of its range. Under the policy, a portion of the range of a species is defined as "significant" if the species is not currently endangered or threatened throughout all of its range, but the portion's contribution to the viability of the species is so important that, without the members in that portion, the species would be in danger of extinction, or likely to become so in the foreseeable future, throughout all of its range.

Quote from Service Director Dan Ashes

View the News Release
View the Final Policy
View the Federal Register notice
Get answers to frequently asked questions


Until the policy goes into effect on July 31, 2014, the Services have an obligation to meet statutory timeframes and make determinations in response to petitions to list, reclassify, and delist species. During this interim period, the Services will consider the interpretations and principles in this final policy as nonbinding guidance in making individual listing determinations. As nonbinding guidance, the Services will apply these interpretations and principles only as the circumstances warrant, and the agencies will independently explain and justify any decision made in this interim period in light of the circumstances of the species under consideration. In preparing this final policy, the Services considered all comments and information received during the comment period on the proposed policy.

Last updated: October 2, 2014