Last week the U.S. Fish and Wildlife Service ("FWS") and the National Marine Fisheries Service ("NMFS") (collectively, the "Services") finalized a rule defining the term "habitat" as used for designating "critical habitat" under the Endangered Species Act (the "ESA"). The ESA requires the Services to designate critical habitat for threatened and endangered species to conserve the ecosystems relied upon by these species. By definition, “critical habitat” includes both areas occupied and unoccupied by the species that are “essential to the conservation of the species.”

Readers of this blog may recall that in Weyerhaeuser Co. v. U.S. Fish and Wildlife Service (2018), the Supreme Court vacated the Fifth Circuit Court of Appeals’ decision to uphold a determination by the Services which designated an unoccupied area as “essential” for the endangered Dusky Gopher Frog despite the area’s lack of an open-canopy – a feature that the Services deemed essential in its occupied habitat designation. The Supreme Court opined that in order for habitat to be designated critical habitat, the Services must first determine if the area at issue is indeed habitat for the endangered species (more discussion here). For many, the opinion was an about-face as to the scope of critical habitat but before another opinion was issued on remand, the Services stepped in and promulgated this rule in response.

The final rule, which only applies to critical habitat rules proposed after January 19, 2021, provides:

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.

In the comments to the final rule, the Services stressed that this rulemaking was not intended to create new a regulatory step or process, rather their intent was to provide a clear definition of “habitat” that is both consistent with Weyerhaeuser and broad enough to allow for both occupied and unoccupied areas to be designated as “critical habitat,” as required by Section 3 of the ESA. Crucially, the “habitat” definition requires an area either "currently or periodically" contain the resources and conditions necessary to support a threatened or endangered species. Critics of the rule argue that this language narrows the scope of what could otherwise be considered habitat by excluding areas that don't have the necessary conditions now but could have the necessary conditions in the future should the species require additional or new habitat due to climate change.

A lawsuit challenging the final rule has already been filed by various attorney generals in the Northern District of California under the Administrative Procedures Act. The challenge is one to watch as a narrowed application of the definition could have significant consequences for species throughout the United States.