Today, the U.S. Departments of the Interior and Commerce announced that the U.S. Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS) (together, the Services) published a final rule rescinding the agencies’ longstanding regulatory definitions of “harm” under the Endangered Species Act (ESA). The rule finalizes their April 2025 proposal and is scheduled to take effect on September 14, 2026. Once effective, the rule will remove the definitions of “harm” from 50 C.F.R. §§ 17.3 and 222.102 without replacing them with new regulatory text.

Key Takeaways

• The Services will no longer interpret habitat modification or degradation, standing alone, as a prohibited “take” of listed wildlife.
• Activities that affect habitat but do not otherwise kill, injure, capture, or directly affect listed animals may no longer require incidental-take authorization under ESA Section 7 or Section 10.
• The rule does not alter ESA Section 7 consultation, jeopardy, or critical-habitat obligations for federal actions, but habitat modification will no longer independently support an incidental take statement. Applicable state protections will remain in place.
• The Services will not reopen existing permits and incidental take statements solely because of the change. Pending authorizations may require a new assessment under the Services’ narrower interpretation.

What the Final Rule Changes

The Services’ existing regulatory definitions provide that “harm” includes significant habitat modification or degradation that actually kills or injures listed wildlife by significantly impairing essential behavioral patterns such as breeding, feeding, or sheltering. The ESA defines “take” to include “harm,” along with harassing, pursuing, hunting, shooting, wounding, killing, trapping, capturing, or collecting wildlife, or attempting to engage in that conduct. The statute does not separately define “harm,” which enabled the Services to define the term in their ESA regulations. Once effective, the amendment will rescind those definitions, rendering “harm” an undefined statutory term.

In the preamble to the final rule, the Services attempted to address questions raised in public comments to their proposed rule. In public comments, stakeholders requested clarification about whether habitat modification could still qualify as “harm” in particular circumstances. The final rule’s preamble reiterates that habitat modification or degradation does not, by itself, qualify as “take”—an interpretation endorsed by Justice Scalia’s dissent in Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, where a majority of the Supreme Court upheld FWS’s contrary prior definition of harm. Under the Services’ new interpretation, “harm” requires an affirmative act directed immediately and intentionally against a particular animal, not an act or omission that indirectly and accidentally injures a population of animals.

Who Is Affected?

The rule will be most consequential for landowners and businesses whose activities alter habitat but do not otherwise involve direct interactions with listed species.

Under Section 9, the Services will no longer treat habitat modification or degradation, standing alone, as prohibited harm resulting in take. As a result, project proponents generally will not need incidental-take authorization where habitat modification is the only potential basis for take. Applicants seeking permits for conduct that otherwise constitutes take also generally will not need to address habitat modification through conservation-plan mitigation or alternatives. For FWS-issued permits, the preamble states that Interior will no longer impose permit terms directed solely at habitat modification or degradation.

The rule does not eliminate ESA Section 7 requirements. Federal agencies must still ensure that actions they authorize, fund, or carry out are not likely to jeopardize listed species or destroy or adversely modify designated critical habitat. Habitat effects may therefore remain relevant to consultation, even though they will no longer constitute harm on their own. An incidental take statement may no longer be needed where habitat modification was the only anticipated source of take, but other direct effects on listed species may still require authorization and trigger avoidance and minimization measures. Moreover, the rule does not alter the existing definition of “harass” in 50 C.F.R. § 17.3, which forms another basis for take; a future Services rulemaking may address that separate provision and any habitat-related considerations thereunder.

The final rule is prospective only. Existing incidental take authorizations will remain in effect. The rule also does not automatically remove habitat-related conditions from existing authorizations. Holders of such authorizations might approach the Services for amendments consistent with the new rule.

The rule provides less clarity for pending permit applications and consultations because it does not establish a transition process. Parties with pending matters should reassess whether the new interpretation changes the anticipated take, proposed mitigation, or need for ESA authorization.

The Services are also considering whether regulations governing FWS habitat conservation plans and incidental take permits should be updated to reflect the new interpretation. Applicable Section 4(d) rules for threatened species remain in effect, though FWS has not yet taken final action on its latest proposal to rescind its “blanket 4(d) rule.”

Legal Challenges Are Likely

The final rule is likely to face legal challenges. In Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, the Supreme Court upheld FWS’s prior definition of “harm” as a reasonable interpretation of the ESA. That definition included habitat modification that actually kills or injures wildlife. But the Court expressly declined to decide whether the ESA compelled that interpretation.

The Services argue that Sweet Home therefore leaves room to change the interpretation. They characterize the decision as holding only that the prior definition was permissible, not that it was the best reading of the statute. Relying on the Supreme Court’s 2024 Loper Bright decision, sharply limiting judicial deference to agencies’ interpretations of the statutes they administer, the Services now conclude that the prior definition does not reflect the best reading of the ESA and adopt the reasoning of Justice Scalia’s Sweet Home dissent.

Challenges will likely test whether the Services may adopt that narrower reading despite Sweet Home’s statutory analysis and Loper Bright’s statement that prior decisions applying Chevron remain subject to statutory stare decisis. Challenges may also focus on the Services’ claim that the rulemaking is exempt from National Environmental Policy Act (NEPA) review or ESA consultation because it purportedly was a nondiscretionary action under Loper Bright. Until courts resolve those issues and the Services provide further implementation guidance, the rule may reduce federal permitting obligations for habitat-modifying activities while creating new uncertainty about the boundary between indirect habitat effects and prohibited take. And particularly if a court preliminarily or permanently enjoins the rule, project proponents could be subject to substantial uncertainty about ESA obligations in the near term.

Practical Next Steps

Project proponents should separate three questions that were often addressed together under the former definition: whether an activity directly takes listed wildlife, whether it modifies habitat, and whether it has a federal nexus that triggers Section 7 consultation. They should also review applicable state laws, reassess pending permit and consultation strategies, and continue complying with existing authorizations unless those authorizations are formally changed.

The final rule may provide meaningful permitting relief, but it does not create a general exemption for activities affecting listed species or their habitats. Its practical value will depend on the type of effect, the species involved, the presence of discretionary federal action, applicable state protections, implementation across the Services’ field offices nationwide, and the outcome of expected litigation.

Beveridge & Diamond’s Endangered Species and Wildlife Protection practice group provides strategic counseling and compliance advice to project and product proponents in all industries to minimize the impacts of threatened and endangered species listings and critical habitat designations on our clients’ activities. For more information or to discuss strategies for efficiently navigating your project or product through the complex and overlapping federal regulatory programs, please contact the authors.