The U.S. Fish and Wildlife Service (FWS) and the National Marine Fisheries Service (NMFS) (collectively, the Services) proposed four rules that would modify key Endangered Species Act (ESA) regulations. Two of the proposed rules were issued jointly by the Services, and two were issued solely by FWS. Together, these proposed changes would restore regulatory changes promulgated under the first Trump administration in 2019 and 2020 that largely were rescinded by the Biden administration in 2022 and 2024, while adding clarifications intended to improve transparency and align regulatory standards more closely with longstanding agency practice.
The proposals would affect several foundational ESA processes, including listing and delisting determinations, critical habitat designations and exclusions, threatened species protections, and interagency consultation requirements. Per the Services, these proposed changes aim to better reflect the statutory text, provide clearer guidance to the regulated community, and enhance the predictability and consistency of ESA implementation. As with other recent ESA regulatory changes, these changes, if adopted, are likely to engender litigation.
Interested parties have until December 22, 2025, to submit comments on the agencies’ proposals.
Section 4: Species Listing and Critical Habitat Designation
The Services jointly propose revisions under Section 4 of the ESA, which governs the listing of species as threatened or endangered and the designation of critical habitat for listed species. The proposed changes would address how the Services evaluate species for potential listing, delisting, or reclassification, and how they determine when and where to designate critical habitat. The rule, if finalized as proposed, would largely restore regulatory language adopted in 2019, yet rescinded in 2022.
The revisions focus on clarifying the standards for listing determinations, when designating critical habitat may be considered “not prudent,” and the approach the Services must follow when designating unoccupied areas as critical habitat.
- “Foreseeable future.” When listing a threatened species, the Services propose to restore the 2019 regulatory definition for whether the species is likely to become an endangered species in the “foreseeable future.” Under the proposed standard, the “foreseeable future” would extend only so far into the future as the Services can reasonably determine, based on the best scientific and commercial data available, that both the future threats and the species’ responses to those threats are likely.
- “Not prudent” critical habitat determinations. The proposal would reinstate language providing that designating critical habitat may not be prudent when the only threats to the species’ habitat stem solely from causes that cannot be addressed by management actions identified in a Section 7 consultation.
- Designating unoccupied critical habitat. The proposed rule would restore the 2019 requirement that the Services must first evaluate areas occupied by the species and designate unoccupied critical habitat only where occupied areas alone are inadequate to support the species’ conservation.
In addition, FWS proposes to restore regulations issued in 2020 and rescinded in 2022 with respect to how the agency evaluates critical habitat designations (including declining to designate), impacts to designated critical habitat, and critical habitat exclusions. The proposed changes would apply only to FWS, as NMFS did not modify its parallel regulations in 2020 and 2022.
- Economic analysis and disclosure of impacts. When proposing critical habitat, FWS would be required to issue a draft economic analysis, and the accompanying Federal Register notice would identify known economic, national security, or other relevant impacts associated with the proposed critical habitat designation.
- Exclusion analysis. The proposal specifies that FWS would analyze excluding an area from a critical habitat designation under Section 4(b)(2) in two circumstances: (1) when a proponent provides “credible information” supporting exclusion of a specific area from the critical habitat designation; or (2) when the Secretary otherwise exercises discretion to evaluate an area for exclusion.
- Mandatory exclusion. If, after conducting its Section 4(b)(2) exclusion analysis, FWS determines that the benefits of excluding an area from a critical habitat designation outweigh the benefits of including it, the agency would exclude that area unless doing so would result in the species’ extinction.
Section 4(d): Elimination of the “Blanket Rule” for Newly Listed Threatened Species
In an effort to reinstate another important aspect of the 2020 regulatory changes, FWS again proposes to eliminate its so-called “blanket 4(d) rule” under which newly listed threatened species automatically receive the same protections that apply to endangered species unless FWS adopts a species-specific rule. (NMFS has no such blanket rule and evaluates each threatened species individually.)
Under the proposal, FWS would have to complete a species-specific 4(d) assessment for each threatened species listed on or after the effective date of the final regulation to determine whether to extend the ESA’s full protections to the species. The species-specific rule would:
- Include a written “necessary and advisable” determination tailored to the species’ conservation needs;
- Consider economic and other relevant impacts; and
- Undergo public notice and comment.
The proposed rule would apply only prospectively to threatened species after the rule becomes effective. Threatened species currently covered by the existing blanket rule would not be automatically reevaluated and would continue to receive blanket rule protections unless FWS issues a species-specific 4(d) rule for that species. FWS would still have discretion to propose revisions to any 4(d) rule protections if new information or management needs warrant changes.
Section 7: Agency Consultations
FWS and NMFS jointly propose revisions to their regulations under Section 7 of the ESA, which requires federal agencies to consult with the Services on any proposed federal action to ensure the action would not jeopardize the continued existence of a listed species or result in the destruction or adverse modification of designated critical habitat. The proposed rule would largely restore the Services’ 2019 regulatory framework by reversing several 2024 changes.
The revisions focus on how federal agencies identify the environmental baseline, determine the effects of a proposed action, and assess whether those effects are “reasonably certain to occur.”
- Environmental baseline. The Services propose returning to the 2019 definition, under which the baseline reflects the existing condition of the species and its critical habitat in the action area, separate from the consequences caused by the proposed action. This definition would clarify that components of federal activities or facilities over which the agency has no discretion are not a consequence of the action. Impacts from those nondiscretionary activities and facilities would be included in the environmental baseline.
- Effects of the action. The proposed rule would limit consideration of “effects” to those that are both caused by the proposed action (i.e., it would not occur but for the action) and reasonably certain to occur. The Services also propose to restore and clarify factors relevant to determining whether an effect is “reasonably certain,” including temporal and geographic remoteness, the complexity of the causal chain, and whether the action agency could prevent the effect.
These proposed revisions place a stronger emphasis on causal connection and predictability in identifying an action’s effects. The proposed rule would apply prospectively to Section 7(a)(2) consultations occurring after the effective date of the final rule; it would not require reopening previously completed consultations.
Conclusion and Implications
If adopted, the proposed rules would significantly change how the Services currently implement several core ESA provisions, but they would largely mirror the regulatory program in place in the latter part of the first Trump administration and the first half of the Biden administration. The proposals would restore earlier regulatory frameworks for listing decisions, critical habitat designations, and interagency consultations, while replacing the “blanket rule” for threatened species with a species-specific approach under Section 4(d).
For project proponents, permit applicants, and other regulated entities, these changes would provide greater transparency and predictability by clarifying the analytical standards that govern listing, critical habitat, and consultation decisions.
The Section 4 Proposed Rule, Listing Species and Designating Critical Habitat (Joint Services Rule), can be found here.
The Section 4 Proposed Rule, Regulations for Designating Critical Habitat (FWS-Only Rule), can be found here.
The Section 4(d) Proposed Rule, Regulations Pertaining to Endangered and Threatened Wildlife and Plants (FWS-Only), can be found here.
The Section 7 Proposed Rule (Joint Services Rule), Interagency Cooperation Regulations, can be found here.
