Proposed rules would reverse Biden-era regulations under the ESA and return to the regulatory framework implemented during the first Trump administration.

By Nikki Buffa, Jennifer K. Roy, and Janice M. Schneider

Key Points:

  • The proposed rules would revise definitions and analysis standards for interagency consultations, move toward species-specific rather than blanket protections, and increase agency discretion in determining protected habitat.
  • The US Fish and Wildlife Service and the National Marine Fisheries Service are accepting public comment on the proposed rules through December 22, with legal challenges expected to follow.

Introduction

On November 19, 2025, the US Fish and Wildlife Service (FWS) announced four proposed rules (2025 Proposed Rules) that would change how the agency interprets and implements pivotal sections of the Endangered Species Act (ESA). The National Marine Fisheries Service (NMFS) jointly proposed two of the rules with FWS (collectively, the Services). The Services are accepting public comment on the 2025 Proposed Rules through December 22, 2025.

The 2025 Proposed Rules build on other Trump administration actions discussed in this Latham blog post and would (1) narrow the protections for newly listed plants and wildlife, (2) alter the approach to considering factors for listing a species as threatened or endangered and designating critical habitat for listed species, (3) clarify the procedure for excluding areas from a listed species’ critical habitat, and (4) reinstate the 2019 interagency consultation framework.

Reaction to Biden-Era Rules

The first Trump administration issued various regulations under the ESA in 2019, many of which the Biden administration later reversed. The 2025 Proposed Rules would largely rescind regulations issued by the Services under the Biden administration and revert to approaches in the 2019 regulations. According to the Department of the Interior, the 2025 Proposed Rules would “revise Biden administration regulations finalized in 2024 that expanded federal reach, created unnecessary complexity and departed from the [ESA’s] clear language.”1

The Services cite the 2024 Supreme Court decision in Loper Bright Enterprises v. Raimondo and the “Unleashing American Energy” executive order issued by the Trump administration in January 2025 as catalysts for reconsidering the earlier rules.2

The Proposed Rules: Returning to 2019 Approaches

Interagency Cooperation3

Section 7 of the ESA requires federal agencies to consult with FWS or NMFS to ensure that any action authorized, funded, or carried out by such agencies is not likely to jeopardize the continued existence of endangered or threatened species, or result in the destruction or adverse modification of the critical habitat of such species. The regulations that govern interagency consultation under the ESA were overhauled in 2019 by the first Trump administration and again in 2024 under the Biden administration. The 2025 Proposed Rules replace the consultation regulations issued by FWS under the Biden administration with the framework that existed in 2019, with limited exceptions.

The 2025 Proposed Rules would make several changes to definitions and regulations governing interagency consultation processes and analyses, including:

  • Revising the definition of “environmental baseline” in 50 CFR § 402.02 to clarify that the baseline is evaluated at the time of the proposed action, and that it refers to the current condition of the listed species or its designated critical habitat in the action area as would reasonably be expected to occur, without the consequences to the listed species or designated critical habitat caused by the proposed action. The revised definition also clarifies that consequences to a listed species or designated critical habitat from ongoing agency activities or existing agency facilities that are not within the agency’s discretion to modify are part of the environmental baseline — not the proposed action.
  • Reinstating and revising the factors in 50 CFR § 402.17 to consider when determining if a consequence or activity is “reasonably certain to occur,” including the amount of state, tribal, territorial, or local administrative discretion that remains to be exercised with respect to the consequence or activity. This proposal clarifies that the “clear and substantial information” used to make a “reasonably certain to occur” determination must be rooted in the best scientific and commercial information available and not in speculation or conjecture. This proposal also adds two additional factors to consider for determining that a consequence is not caused by the proposed action, including that the agency has no ability to prevent the consequence due to its limited statutory authority (relying on the Supreme Court’s decision in Seven County Infrastructure Coalition v. Eagle County, Colorado) and that the consequence would occur regardless of whether the proposed action moved forward.
  • Revising the “reasonable and prudent measures” that can be included in an “incidental take” statement to eliminate measures that “offset” the impact of incidental take, on the grounds that the concept of offsets is not contained in the statutory text and the term “mitigation” is not used in the portion of the statute related to reasonable and prudent measures.

Protections for Threatened Wildlife and Plants4

Section 9 of the ESA provides a list of prohibitions for endangered species that apply automatically when a species is listed, including the prohibition on “take” of the species. On the other hand, Section 4(d) requires that when a species is listed as threatened, the Secretary of the Interior or the Secretary of Commerce (for marine and anadromous species under National Oceanic and Atmospheric Administration jurisdiction) must issue regulations providing for the conservation of the species and may prohibit, with respect to any threatened species, any act prohibited under Section 9 for an endangered species.

The statutory differences in these provisions have resulted in different approaches for when and how threatened species receive protection under the ESA. In 2019, FWS revoked the long-standing “blanket rule” that applied take prohibitions to all threatened species, and for the first time began applying this protection to newly listed threatened species only through species-specific rules. In 2024 under the Biden administration, FWS reinstated the blanket rule, whereby any newly listed species would receive nearly all the protections allowed by the ESA, including take protection.

The 2025 Proposed Rules would undo the blanket rule approach in favor of issuing species-specific protections for each newly listed threatened species. FWS also proposes that each species-specific rule include a “necessary and advisable” determination that includes consideration of conservation and economic impacts. The changes would not affect species currently protected by the blanket rule, which would continue until species-specific protections are issued.

Listing Endangered and Threatened Species and Designating Critical Habitat5

As a general matter, to receive the significant protections under the ESA, a species must first be listed as endangered or threatened. When determining whether to list a species, among other statutory factors to be considered, the ESA directs the Services to evaluate a species’ risk of extinction in the foreseeable future. The Services must designate critical habitat for the threatened or endangered species concurrently with the listing unless doing so would not be prudent or otherwise determinable.

The 2025 Proposed Rules would restore the 2019 interpretation of the listing, delisting, and critical habitat designation provisions of the ESA, including by:

  • Adopting a narrower definition of and defining “foreseeable future.” Section 3(20) of the ESA defines a “threatened species” as any species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. Current regulations define the “foreseeable future” to extend “as far into the future as the Services can make reasonably reliable predictions about the threats to the species and the species’ responses to those threats.”6 This proposal adopts a narrower definition and defines foreseeable future to extend “only so far into the future as the Services can reasonably determine that both the future threats and the species’ responses to those threats are likely.”7
  • Amending the procedure and criteria that the Services apply when making delisting decisions for the stated purpose of aligning the text more closely with the text of the ESA and delete any reference to “recovery.” This proposal provides that the criteria for delisting a species are the same as the criteria to support a decision not to list a species in the first instance. These criteria are: (1) the species is extinct, (2) the species does not meet the definition of an endangered species or a threatened species, or (3) the listed entity does not meet the definition of a species.
  • Increasing the Services’ discretion to determine when designating critical habitat is “not prudent.” This proposal returns to the 2019 approach, which prioritized a habitat occupied by a listed species over unoccupied areas in determining the boundaries of critical habitat, including providing that unoccupied areas will only be considered essential if limiting a critical habitat designation to occupied areas would be inadequate for the conservation of the species.

Designating Critical Habitat Exclusions8

Once a species is listed, Section 4 of the ESA directs either of the Services to designate critical habitat, which are areas that are “essential for the conservation of the species.” Section 4(b)(2) requires consideration of the economic impact, the impact on national security, and any other relevant impact of designating any particular area as critical habitat. It also authorizes excluding areas from critical habitat if the benefits of exclusion outweigh the benefits of the designation as critical habitat, unless the exclusion “will result in the extinction of the species concerned.” As noted in the regulatory preamble for this proposal, “[c]onducting an exclusion analysis under section 4(b)(2) involves balancing or weighing the benefits of excluding a particular area from a critical habitat designation against the benefits of including that area in the designation.”

In 2016, the Services developed a Policy Regarding Implementation of Section 4(b)(2) of the ESA that provided direction regarding how to exercise discretion in excluding areas from critical habitat designations.9 In 2020, FWS issued a rule revising the approach for conducting exclusion analyses, which the agency rescinded in 2022. The 2025 Proposed Rules would return FWS to the 2020 rule approach.

In particular, this proposal would require FWS to prepare a draft economic analysis when publishing a proposed rule to designate critical habitat. The proposed critical habitat designation must also identify the areas that the Secretary of the Interior considers excluding and explain why. The proposal provides additional detail on how FWS will weigh impacts when conducting an exclusion analysis, including a non-exhaustive list of categories of potential impacts to consider. Notably, the proposal applies only to FWS; if the proposal is finalized, NMFS will continue to implement the 2016 policy and its regulations at 50 CFR § 424.19.

Future Actions and Potential Challenges

California is moving to backstop any reduction in federal ESA protections by adopting state measures that preserve or expand protections. For example, AB 1319 (2025) makes it unlawful to traffic in fish, wildlife, or plants taken in violation of state or federal law as of January 19, 2025, and creates a process for the California Department of Fish and Wildlife (CDFW) to provisionally list species as candidates under the California ESA when federal protections are reduced.10

The law (1) directs CDFW to publish findings and report provisional candidacies to the California Fish and Game Commission, (2) affords provisional candidates the same protections as candidates, and (3) exempts these actions from certain environmental analyses to expedite protections. Together, these steps signal California’s intent to maintain broader species protections despite any federal narrowing under the Trump administration’s regulatory framework.

ESA regulations are frequently subject to litigation. The regulations issued under the first Trump administration were challenged in court, and the cases were not decided on the merits. Conservation groups have already signaled their opposition to the 2025 Proposed Rules and their intent to pursue legal action.11

Latham & Watkins will continue to monitor developments in this area.

The authors would like to thank Liam Grah for his contribution to this blog post.