Trump Admin. Adopts Final Definition of “Habitat” for Species Protected Under Endangered Species Act

Client Alert

Action Responds to a Mandate by the U.S. Supreme Court


Sprinting to finalize yet another significant species regulation while still in power, the Trump administration today finalized its adoption of a regulatory definition of “habitat” for purposes of species protection under the federal Endangered Species Act (ESA or the act). Called for by the U.S. Supreme Court, the new definition clarifies that even if an area potentially may be made to contain requisite features of habitat by human restoration or other artificial or extraordinary means, the absence of at least some such features currently will disqualify such an area from being designated as protected habitat under the act.

The new regulatory definition, published today in the Federal Register (85 F.R. 81411), will become effective on January 15, 2021, less than a week before the inauguration of President-elect Biden. The rule will apply only prospectively for habitat designations occurring on or after January 15, 2021.

Definition of “Habitat”

Although the ESA statutorily defines “critical habitat” and requires its designation as to areas both occupied and not presently occupied by a subject species granted protection under the act, neither the ESA nor its implementing regulations have ever defined the broader term “habitat.” The new rule, to be codified at 50 C.F.R. 424.02, provides the following definition of “habitat”:

Habitat. 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.

Definition Mandated by the U.S. Supreme Court

The first Supreme Court oral argument following the highly contentious confirmation hearing of Associate Justice Brett Kavanaugh was for a widely watched and controversial ESA case in which, it was argued, the U.S. Fish & Wildlife Service (Service) had overreached in mandating protected status for lands which, though historically occupied by a protected species, had long since been converted by commercial logging activities and no longer bore any of the essential features necessary to support the species. This fact was uncontested. However, the Service argued that sufficient restoration efforts could re-establish such features.

The species at issue in the case, Weyerhaeuser v. U.S. Fish & Wildlife Service, 139 S. Ct. 361 (2018), was the dusky gopher frog. Historically, the frog existed throughout Alabama, Louisiana and Mississippi; but at the time of listing, the frog was known to exist only in one pond in Southern Mississippi. The proposed designation of critical habitat for the frog included “Unit 1,” a 1,500-acre area in Louisiana owned by Weyerhaeuser. Logging practices, among other things in the area including Unit 1, had left the physical and biological attributes incapable of supporting the frog. Nonetheless, the Service designated the area as “critical habitat” under the act, stating that it could be converted to supportable habitat.

The ESA defines critical habitat, whether presently occupied or not, as areas “essential to the conservation of the species.” At issue in Weyerhaeuser was whether areas presently devoid of attributes on which a species must necessarily depend may be included by the Service as designated critical habitat based solely on the potential of future restoration efforts to establish such attributes.

On that specific question, the unanimous Court largely punted. The Court instead held that inherent in the notion of statutory “critical habitat” is a broader universe of “habitat.” The Court stated that if an area cannot meet a basic criteria as “habitat” for a given species, it necessarily cannot be part of the narrower category of essential “critical habitat.” Given the act’s and implementing regulations’ failure to identify and define “habitat,” the Court remanded the question back to the Service thus spurring adoption of the new rule.

Components of “Habitat” Definition

Although contained in a single, seemingly straightforward sentence, this definition of “habitat” addresses multiple contentious questions that were subject to extensive public comment in debating the new definition. Specifically highlighted in the preamble for the final rule were the following:

  • The definition is necessarily broad enough to encompass both occupied and unoccupied habitat as it must be given the statutory definition of “critical habitat.”
  • The prefatory clause—“For the purposes of designating critical habitat only”—was necessary to avoid any unintended implications for the concept of “habitat” used or defined elsewhere in law.
  • “Abiotic means derived from non-living sources such as soil, water, temperature, or physical processes. Biotic means derived from living sources such as a plant community type or prey species.” These terms were used to correlate with though not conflate the statute’s terms “physical or biological features” in the definition of critical habitat.
  • “We included the phrase ‘resources and conditions’ to make clear that the definition of ‘habitat’ is inclusive of all qualities of an area that can make that area important to the species. We intend for the word ‘resources’ to describe the common ecological concept—which in general is a source or supply from which a benefit is produced and that has some utility. Likewise, we intend the word ‘condition’ to describe a particular state that something is in. Examples of resources and conditions can include dynamic processes (e.g., riverine sand bar formation or fire disturbance), a set of environmental conditions (e.g., temperature, pH, and salinity), or any characteristics that can satisfy life-history needs (e.g., food, shelter).”
  • Also, the specific “resources and conditions” need not be present at all times. “[W]e intend the definition of ‘habitat’ to include ephemeral habitats—areas that ‘may be variable, both temporally and spatially, such as beach overwash areas, early-successional riparian communities, or riverine sandbars.’ 85 FR at 47335. Therefore, we included ‘periodically’ to clarify that habitat includes ephemeral habitat, which are areas where the resources and conditions are not consistently present but appear at certain times.”
  • “We have retained the phrase ‘one or more life processes’ from the proposed definition for similar reasons, in that we intend for habitat to include areas used during a particular season (e.g., for migratory species) or at a particular phase in the species’ life cycle (e.g., fresh-water spawning habitat versus adult marine habitat). We intend this phrase to have the common biological meaning, that is, to include a series of functions—such as movement, respiration, growth, reproduction, excretion, and nutrition—that are essential to sustain a living being.”


But notwithstanding these provisions assuring inclusiveness, the following speaks most directly to the outer-bound limitation that was at the heart of the Court’s direction in Weyerhaeuser: “At the same time, notwithstanding the inclusion of ephemeral and seasonal habitat in the definition, 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 final rule is available here.



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