Endangered Species Act Final Regulatory Definition of Habitat

A December 2020 final rule defining “habitat” could have important consequences for future designations of lands and waters as “critical habitat” under the Endangered Species Act (ESA). Designation of critical habitat by the U.S. Fish and Wildlife Service or National Marine Fisheries Service (jointly, the “Services”) can affect projects that require federal agency permits or funding, because ESA section 7 requires federal agencies to ensure through consultation with the Services that their actions are not likely to adversely modify or destroy designated critical habitat.

On December 16, 2020, the Services adopted, for the first time, a regulatory definition of habitat, as follows:

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.

85 Fed. Reg. 81,411 (Dec. 16, 2020) (to be codified at 50 C.F.R. § 424.02). This definition will become effective January 15, 2021 and will apply to proposals by the Services to designate areas as critical habitat after January 15. The Services do not intend to reevaluate any prior critical habitat designations on the basis of this rule.

The final definition responds to the US Supreme Court’s November 27, 2018, unanimous decision in Weyerhaeuser Co. v. U.S. Fish & Wildlife Service, 139 S. Ct. 361 (2018), which held an area is eligible for designation as critical habitat under the ESA only if the area is actually habitat for that species. For additional background on Weyerhaeuser Co. and the Services’ initial efforts to address Weyerhaeuser, including the Services’ proposed definition of habitat, see our September 16, 2020 blog post .

In response to comments on the Services’ proposal and upon further consideration, the Services’ final definition modifies the proposed definition and proposed alternative definition and further clarifies the regulatory scope of habitat. The key aspects of the final definition include the following:

• Introductory Phrase. The Services added the introductory phrase: ‘‘For the purposes of designating critical habitat only,’’ to explicitly limit the definition’s applicability to the designation of critical habitat. This clarification is intended to address concerns about the potential for the definition to apply to other sections of the ESA or other federal programs that use the term “habitat.”

• “Abiotic and Biotic Setting.” The Services replaced the proposal’s phrase “physical places” with “abiotic and biotic setting” to capture a broader set of…