On December 15, 2020, the U.S. Fish and Wildlife Service and National Marine Fisheries Service (collectively, the agencies) released a pre-publication version of a final rule providing a definition of “habitat” for the purpose of informing designation of areas as “critical habitat” under the Endangered Species Act.  The agencies released a proposed rule defining habitat in August 2020 in response to a unanimous decision by the U.S. Supreme Court in 2019 overturning a lower court decision that upheld a controversial determination of critical habitat by the U.S. Fish and Wildlife Service for the dusky gopher frog.  Weyerhaeuser Co. v. U.S. Fish and Wildlife Service, 139 S.Ct. 361 (2018).

The final definition (to be codified at 50 C.F.R. § 424.02) is:

For the purposes of designating critical habitat only, habitat is the abiotic and biotic setting that currently or periodically contains the resources and conditions necessary to support one or more life processes of a species.

The final rule will be effective 30 days from December 16, 2020, the date it is published in the Federal Register.  The most notable aspects of the definition are:

• the definition is being promulgated for the limited purpose of informing designation of critical habitat
• “currently or periodically” is intended to encompass ephemeral habitat
• “resources and conditions” include dynamic processes and environmental conditions
• “necessary to support” applies to areas needed for one or more of a species’ life processes

Of note, the final rule does not extend the definition of habitat to geographic areas that do not currently or periodically contain the resources and conditions necessary to support one or more life processes of a species, but that could in the future do so as a result of human intervention.  Some may contend that in light of this fact the definition is too narrow, while others would argue that expanding it in such a manner would decouple the definition from its scientific meaning.

Doubtless, there will be calls from some quarters for the Biden Administration to repeal or amend the rule, and there also may be legal challenges to the rule in court.  We will track and report on significant developments as they unfold.