The Departments of Commerce and the Interior (Departments) have completed a proposed rule to define the term “habitat” as that term is used in the context of designating “critical habitat” under section 7(a)(2) of the Endangered Species Act (ESA). The proposed rule will soon be published in the Federal Register. Upon publication, the public will be given 30 days to submit comments. If finalized, the definition will be included in the joint regulations developed by the two Departments to implement section 4(a)(3)(A)(i) of the ESA. The ESA, itself, defines the term “critical habitat” but does not define the broader term “habitat.”

The move by the Departments to define “habitat” is substantially a consequence of a ruling by the U.S. Supreme Court in 2018 in a case involving a challenge to a rule promulgated by the U.S. Fish and Wildlife Service to designate critical habitat for the endangered dusky gopher frog (Rana sevosa). Weyerhaeuser Co. v. U.S. Fish and Wildlife Serv., 139 S. Ct. 361 (2018). The Court set aside the rule, opining in relevant part:

“According to the ordinary understanding of how adjectives work, ‘critical habitat’ must also be ‘habitat.’ Adjectives modify nouns—they pick out a subset of a category that possesses a certain quality. It follows that ‘critical habitat’ is the subset of ‘habitat’ that is ‘critical’ to the conservation of an endangered species.”

In the soon-to-be-published rule, the Departments provide context for their proposal then describe a two sentence definition:

“The physical places that individuals of a species depend upon to carry out one or more life processes. Habitat includes areas with existing attributes that have the capacity to support individuals of the species.”

The proposal also includes an alternate definition of “habitat” upon which the Departments seek comment.

The proposed definitions are consistent with the notions that (i) habitat is a species-specific concept and (ii) a geographical area must be capable of supporting a species for all or a portion of its life cycle to be considered habitat for a species. One challenge associated with defining “habitat” is that habitat is dynamic in space and time. That said, including a definition in the regulations will create a more transparent regulatory regime to implement consultation under section 7(a)(2) of the ESA.