On August 5, 2020, the United States Fish and Wildlife Service (“FWS”) and the National Marine Fisheries Service (“NMFS”) (collectively “the Services”) issued a proposed rule defining the term “habitat” under section 4 of the Endangered Species Act (“ESA”). In the ESA, “habitat” is used in the context of “critical habitat,” a term that the statute defines to include areas which have the “physical and biological features” that are “essential to the conservation” of the species that the habitat has been designated to protect. However, the ESA does not define the term “habitat,” and the Services have never before sought to define the term through regulation. In a 2018 decision, the United States Supreme Court concluded that what was considered “habitat” must be broader than what was considered “critical habitat” under the ESA. Given the Supreme Court’s decisions, the Services have proposed a regulatory definition of “habitat” under the ESA.

“Critical Habitat” in the ESA

The ESA was passed in 1973, and provides the federal framework for the protection and conservation of at-risk species. It is administered by both FWS and NMFS. Traditionally, NMFS oversees marine wildlife and anadromous fish, while FWS is responsible for terrestrial and freshwater organisms. The Services are required by the ESA to maintain a list of threatened and endangered species that receive protection under the Act. One of those protections is the designation of critical habitat. When one of the Services lists as species as threatened or endangered under the ESA, it must also designate critical habitat for the species.

Under the ESA, critical habitat is broken up into two categories. The first category contains “the specific areas within the geographical area occupied by the species, at the time it is listed […] on which are found those physical or biological features essential to the conservation of the species[.]” The second category includes “specific areas outside the geographical area occupied at the time it is listed” if the listing agency determines that “such areas are essential for the conservation of the species.” Importantly, critical habitat may not include the entire geographical area which can be occupied by the species, unless the listing agency determines that it should.

Once an area is designated as critical habitat, it receives some ESA protections of its own. Under the ESA, federal agencies must ensure that any action they carry out, fund, or authorize will not destroy or adversely modify critical habitat. If a federal agency determines that its action may destroy or adversely modify critical habitat, then it must consult with the Services to mitigate the outcome.

Weyerhaeuser Co. v. U.S. FWS

In 2018, the United States Supreme Court published its opinion in Weyerhaeuser Co. v. U.S. Fish & Wildlife Service, 139 S. Ct. 361 (2018). The case concerned the designation of critical habitat for the dusky gopher frog, a type of frog found in the southern United States. The frog was listed as an endangered species by FWS in 2001. When FWS was designating critical habitat for the frog, it included an area in St. Tammany Parish, Louisiana where the frog had once lived, but had long been used for commercial timber harvesting. The frog had not been in that area for decades prior to FWS designating it critical habitat. However, FWS believed that the area fell into the category of unoccupied critical habitat because it contained features that made it essential for the conservation of the frog.

The plaintiffs in the case owned the area in St. Tammany Parish that FWS designated as critical habitat. They brought a lawsuit against FWS arguing that FWS had used the wrong methodology to determine that the St. Tammany Parish area was critical habitat. Specifically, the plaintiffs argued that habitability was a requirement for critical habitat. In other words, the plaintiffs argued that for an area to be critical habitat, it had to first be habitat. Although the lower courts found in favor of FWS, the Supreme Court found in favor of the plaintiff. The Court held that “an area is eligible for designation as critical habitat under [the ESA] only if it is habitat for the species.” The Court also noted that while the ESA defined the term “critical habitat,” there was no corresponding definition for the term “habitat.” While it reasoned that the definition must be broader than “critical habitat,” it did not define the term.

Proposed Definition

In response to Weyerhaeuser Co. v. U.S. FWS, the Services have proposed, for the first time, a definition for “habitat” under the ESA. According to the Services, the definition of “habitat” must be broader than the statutory definition of “critical habitat” in order to make sense under the ESA. The definition must also be broad enough to include both occupied critical habitat and unoccupied critical habitat because the ESA defines “critical habitat” to include both occupied and unoccupied areas.

With that in mind, the Services have proposed the following 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 Services have also proposed an alternate definition:

The physical places that individuals of a species use to carry out one or more life processes. Habitat includes areas where individuals of the species do not presently exist but have the capacity to support such individuals, only where the necessary attributes to support the species presently exist.

Both definitions, according to the Services, were drafted to reflect the understanding that that a species’ habitat is based off of its ecology. However, the Services also acknowledge that no definition of “habitat” that they reviewed was broad enough to include unoccupied habitat, which the text of the ESA requires the Services to consider. Therefore, the proposed definitions have been written intentionally broad to capture both occupied and unoccupied habitat.

What Next?

Because this is a proposed rule, it is open for comment from the public. In this case, the Services are asking for comments on specific portions of the proposed definitions, including the “depend upon” language in the first definition, and the second sentence in the alternate definition. The comment period will last from August 5, 2020 to September 4, 2020.

While defining the term “habitat” under the ESA is not expected to add any additional step to the ESA procedure, it could change how the Services designate critical habitat. The main issue in Weyerhaeuser Co. v. U.S. FWS was that at the time the St. Tammany Parish area was designated as critical habitat for the dusky gopher frog, the frog could not have lived in the area unless modifications were made. If “habitat” under the ESA is defined as “areas where individuals of the species do not presently exist but have the capacity to support such individuals, only where the necessary attributes to support the species presently exist,” then the area at issue in Weyerhaeuser would never have been designated as critical habitat in the first place.

To see the proposed definition for “habitat,” click here.

To read the text of Weyerhaeuser Co. v. U.S. FWS, click here.

To read the text of the ESA, click here.

For more National Agricultural Law Center resources on the ESA, click here.