On June 7, the U.S. Fish and Wildlife Service (FWS) issued a proposed rule titled, “Endangered and Threatened Wildlife and Plants; Designation of Experimental Populations.” In issuing the proposed rule, FWS re-affirms its authority to designate and introduce experimental populations of protected species into areas of habitat outside of their historical range when climate change, invasive species, or other threats have affected or will affect that range. Importantly, this proposal only applies to species managed by FWS. Species managed by NMFS are governed by separate regulations, which NMFS updated back in 2016. These changes will make the FWS regulations more similar to those of NMFS. Pursuant to NMFS’ existing regulations, experimental populations of salmon have been re-introduced in certain waterways in the Western United States. FWS’s proposal could result in similar re-introduction of experimental populations of terrestrial and freshwater species.

FWS’ proposed regulations relate to Section 10(j) of the Endangered Species Act (ESA), 16 U.S.C. § 1539(j), which allows FWS to establish and release into the wild experimental populations of ESA-listed species, both threatened or endangered. Section 10(j) specifically gives FWS authority to release experimental populations outside the current range of species if the secretary determines that such release will further the conservation of such species. Regulations implementing this section, adopted in 1984, establish that experimental populations can be released into suitable natural habitat outside the species’ current natural range (but within its probable historical range, absent a finding by the director in the extreme case that the primary habitat of the species has been unsuitably and irreversibly altered or destroyed). See 50 C.F.R § 17.81(a).

When the regulations were originally developed, the agency did not contemplate climate change impacts on habitat, which could result in situations where no habitat remains within the historical range. This is the case for the Florida Key deer and Key Largo woodrat, for example — species whose habitat is expected to be underwater in the coming decades due to climate change. Similarly, in some instances, formerly suitable habitat within the historical range has undergone irreversible decline or change, rendering it unable to support the species. The FWS is proposing these amendments to adjust for these potential scenarios.

This proposal also follows controversy relating to when and how unoccupied habitat can be designed as critical habitat for listed species. Although the proposal is not intended to directly address a definition of habitat or the Supreme Court case Weyerhaeuser Co. v. U.S., it supports the agency’s approach that habitat should be broad enough to include areas that could meet the ESA’s conservation purpose. The FWS took that approach when it announced a recission of the Trump-era Critical Habitat Rule at the end of 2021 (rule pending OIRA’s review before being finalized). See 86 Fed. Reg. 67,013 (Nov. 24, 2021).

FWS’s proposal stated that it will be accepting comments on the proposed rule through August 8.