Federal ESA Rules Face Overhaul—California Prepares to Fill the Gap

As we speed towards 2026, the federal government has taken steps to resuscitate regulations adopted by the first Trump administration related to the implementation of the Endangered Species Act (ESA). The U.S. Fish and Wildlife Service (FWS) has published four proposed rules—two in conjunction with the National Marine Fisheries Service (NMFS)—and proposed changes that largely revert the regulations back to what the previous Trump administration put in place in 2019.

These proposed regulations would:

• Modify elements of the process for the listing of endangered and threatened species and critical habitat designation (50 CFR 424)
• Make changes to the Section 7 consultation with FWS and NMFS (50 CFR part 402)
• Change protections for threatened species under section 4(d)
• Change critical habitat exclusions (50 CFR 17; section 4(b)(2))

The proposed revisions are prospective in nature and would not affect current listed species or critical habitat designations.

The comment period for these proposed rules is open until Dec. 22, 2025. Comments may be submitted electronically on the Federal eRulemaking Portal or by visiting the links above.

Why are FWS and NMFS Proposing Rule Revisions?

According to the FWS press release, the proposed changes are part of the Trump administration’s broader efforts to “strengthen American energy, improve regulatory predictability, and ensure federal actions align with the best reading of the law.” FWS and NMFS have indicated that the proposed rules are, in part, a response to executive orders (EO) issued in early 2025, primarily EO 14154 “Unleashing American Energy” and EO 14219 “Ensuring Lawful Governance and Implementing the President’s Department of Government Efficiency Deregulatory Initiative.” These EOs directed agencies to review rules that impose “undue burdens” or lack “clear statutory authority.” The proposed changes also respond to pending lawsuits challenging 2019 and 2024 rules implementing the ESA as well as the 2024 Supreme Court decision in Loper Bright Enterprises v. Raimondo, which overturned prior caselaw that had accorded judicial deference to an agency’s reading of a statute (commonly referred to as “Chevron deference”).

These proposed regulations follow earlier steps by the current administration to modify regulatory burdens. Other examples include FWS and NMFS’s proposed rulemaking to rescind the regulatory definition of “harm,” FWS’s request for input on changes to Section 10 permitting regulations, and the Department of Interior’s request for comments on regulatory reform.

Proposed Changes to Species Listing and Critical Habitat Designation (50 CFR Part 424)

The proposed rule revises factors for listing, delisting and reclassifying species under the ESA to return to the version of these regulations promulgated in 2019.

• Economic Impacts: The proposed rule removes the phrase “without reference to possible economic or other impacts of such determination” when making classification determinations. This change would mean that classification determinations could consider economic impacts when evaluating listings and critical habitat designations.
• Foreseeable Future: Under the ESA, a “threatened species” is any species that is likely to become an endangered species in the “foreseeable future.” The proposed rule would change the definition of “foreseeable future” to “extend only so far into the future as FWS and NMFS can reasonably determine that both the future threats and the species’ responses to those threats are likely.” This change likely narrows the definition of threatened species.
• Delisting Species: The proposed rule makes the parameters for delisting the species the same as the standards for deciding not to list a species in the first instance. Current criteria includes delisting a species if it has recovered. The proposal removes the reference to recovery and modifies the delisting criteria to include three circumstances in which it is appropriate to delist a species: (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.

The proposed rule also makes revisions to the criteria for designating critical habitat:

• No-Prudent Determinations: The proposed rule enumerates specific circumstances in which the FWS and NMFS may find that it is not prudent to designate critical habitat, including when threats to a species’ habitat stem solely from causes that cannot be addressed by management actions identified in a Section 7(a)(2) consultation.
• Designating Unoccupied Areas: The proposed rule would make it so that FWS and NMFS cannot designate unoccupied areas as critical habitat unless the occupied areas are “inadequate to ensure the conservation of species.”

Both of these revisions will likely result in less areas considered for and designated as critical habitat.

Proposed Changes to Section 7 Consultation (50 CFR part 402)

Under Section 7 of the ESA, federal agencies are required to consult with FWS and NMFS to ensure that any federal action is not likely to jeopardize the continued existence of listed species or result in the destruction or adverse modification of critical habitat. The proposed rule largely reinstates the interagency cooperation regulations in place during the first Trump administration, which provide a framework for how the Section 7 consultation is to be carried out. The rule clarifies that non-discretionary federal action is not subject to Section 7 consultation.

In addition, the proposed rule:

• Changes the definition of “effects of the action” by limiting the effects to those that are a causal response reasonably certain to occur and that would otherwise not occur but for the proposed action.
• Clarifies when activities and effects are “reasonably certain to occur” by providing a non-exhaustive list of factors that must be considered by agencies.
• Changes the definition of “environmental baseline” to refer to the current condition of the species or its designated critical habitat as would reasonably be expected to occur without the consequences caused by the action at the time of the proposed action.
• Removes the option for offsetting as a reasonable and prudent measure in an incidental take statement.

Proposal to Remove the “Blanket Rule” for Threatened Species (50 CFR part 17; section 4(d))

Section 4(d) of the ESA directs the secretary of the Interior to issue protective regulations deemed “necessary and advisable for the conservation of” threatened species. Section 9 of the ESA provides a specific list of prohibited actions related to endangered animals but does not provide these same prohibitions for plants or threatened animals. The current 4(d) “blanket rule” extends a majority of the Section 9 protections that apply to endangered species to threatened species.

The proposed rule would eliminate the “blanket-rule” and instead require FWS to issue species-specific 4(d) rules (or prohibited actions) for newly listed threatened species. The FWS argues that removing the “blanket rule” allows for more tailored protection of threatened animals.

NMFS does not have a corresponding 4(d) “blanket rule” and currently develops specific 4(d) rules for each threatened species.

Proposed Changes to Critical Habitat Exclusion Analysis (50 CFR part 17; section 4(b)(2))

Under Section 4(b)(2) of the ESA, when FWS designates critical habitat for listed species, it may exclude an area from designation if it determines that the benefits of excluding outweigh the benefits of including the area in a critical habitat designation. The proposed rule, which only applies to FWS’s implementation of the ESA, articulates when and how FWS will undertake an exclusion analysis when designating critical habitat. Among other things, the proposed regulation requires FWS to consider the economic impact, impact on national security and any other relevant impacts prior to designation.

Response in California

Perhaps anticipating actions by the federal government that might reduce federal protection of threatened and endangered species, the California State Legislature passed Assembly Bill (AB) 1319, which was signed into law in October 2025. AB 1319 directs the California Department of Fish and Wildlife (CDFW) to monitor federal actions that may decrease federal protections for endangered or threatened species. If the CDFW finds that such actions would “substantially impact” federally listed species, it may provisionally list those species as long as it determines that doing so would “significantly reduce” the impact. Under AB 1319, a “federally listed species” must be (1) native to California, (2) listed or a candidate for listing under the federal ESA as of Jan. 1, 2025, and (3) not currently protected by the California Endangered Species Act (CESA) (Fish and Game Code Section 2050 et seq.). The bill defines a decrease in federal protections to be an action that reduces the level of protection provided to a federally listed species, including, but not limited to, delisting species, changing the listing status of species from endangered to threatened, eliminating or changing the prohibitions on take, or decreasing the amount of mitigation required for permits or other approvals. The provisional listing of a species under AB 1319 does not affect the obligations of entities that are operating under a federal “take” authorization that was in place as of Jan. 19, 2025. The bill will automatically be repealed on Jan. 1, 2032.

AB 1319 could step in to protect species affected by the proposed federal rules—for example, if a federally threatened species loses section 4(d) protections or is delisted—but only if CDFW determines that the federal change will substantially impact a specific species and that provisional listing will significantly reduce that impact.

And in the background, CDFW and the California Fish and Game Commission continue to work through a list of pending petitions to list species under CESA. These include: burrowing owl, white sturgeon, southern resident killer whales, pacific pocket mouse, western spadefoot toad and petitions for 23 different plant species. Unlike the ESA, species that the Fish and Game Commission finds may meet the standard for listing (i.e., “candidate species”) receive full protection under state law. The standard to find a species qualifies as a candidate species is a relatively easy hurdle. The Fish and Game Commission will be taking further action to process and decide these petitions over the course of 2026.

Conclusion

As this year has shown, the regulatory landscape for wildlife permitting continues to fluctuate. If you are involved in projects that require state or federal approvals that may be impacted by the Endangered Species Act or California Endangered Species Act, Brownstein can assist you in evaluating possible impacts and developing a strategy to respond.

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This document is intended to provide you with general information regarding possible changes to endangered species laws. The contents of this document are not intended to provide specific legal advice. If you have any questions about the contents of this document or if you need legal advice as to an issue, please contact the attorneys listed or your regular Brownstein Hyatt Farber Schreck, LLP attorney. This communication may be considered advertising in some jurisdictions. The information in this article is accurate as of the publication date. Because the law in this area is changing rapidly, and insights are not automatically updated, continued accuracy cannot be guaranteed.