In a case involving the question of when unoccupied habitat may be designated “critical habitat” under the Endangered Species Act (ESA), the U.S. Supreme Court held that critical habitat land must first be habitat before it could be “critical habitat.” Weyerhaeuser Co. v. U.S. FWS, 139 S.Ct. 361 (2018). Given that neither the ESA nor its implementing regulations define habitat, the Court remanded the case for further consideration. In response to this opinion, the U.S. Fish and Wildlife Service and National Marine Fisheries Service (the Services) issued a final rule defining habitat on December 16, 2020. The rule becomes effective on January 15, 2021.

The final rule confirms that habitat includes both occupied and unoccupied areas. The definition finalized by the Services reads 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.

Importantly, the Services explain that “the definition excludes areas that do not currently or periodically contain the requisite resources and conditions, even if such areas could meet this requirement in the future after restoration activities or other changes occur.” The Services also explain that the goal of the introductory clause, “[f]or the purposes of designating critical habitat only,” is to explicitly limit the scope of the definition and prevent unintended consequences on the implementation of other sections of the ESA or other federal programs.

In the preamble to the final rule, the agencies explain that the word “periodically” was included in the definition to clarify that habitat includes ephemeral and seasonal habitats. In addition, they explain that the phrase “one or more life processes” is included so that habitat would include areas used during a particular season or phase in a species’ lifecycle (i.e., migratory or spawning habitat). The Services also explain that a two-step process to determine habitat and then critical habitat is not necessary because the expectation is that most designations would include occupied areas only. The occupancy of the species confirms that the areas constitute habitat for that species.

The definition includes the phrase “resources and conditions” to refer to a broad set of environmental conditions and dynamic processes that can provide benefits to a species, including food, shelter, temperature, salinity, and fire disturbance, among others. The Services clarify that the goal is to determine that there is a reasonable certainty that the area will contribute to the conservation of the species. Similarly, the Services clarify that their use of the term “species” does not preclude considerations of the benefits of the habitat to individual, populations, or metapopulations of a given species as appropriate based on the best available science. The Services also indicate that areas not initially determined to be habitat may subsequently be determined to be habitat. That determination would be made based on the best scientific data available, including data regarding climate change.

The final rule is prospective only, meaning that it would only apply to critical habitat designations initiated after that date. If you have any questions regarding the final rule, please contact Andrea Wortzel or Angela Levin.