When “Harm” No Longer Includes Habitat: Reconsidering the Endangered Species Act’s Take Prohibition
On July 10, 2026, the U.S. Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS) finalized a rule rescinding their regulatory definition of “harm” under the Endangered Species Act (ESA). The change matters because “harm” is one of the acts included in the ESA’s definition of prohibited “take,” and the prior regulation had long treated certain significant habitat modification as unlawful when it actually killed or injured protected wildlife by impairing essential behaviors such as breeding, feeding, or sheltering.
The new rule does not supply a replacement definition. Instead, it deletes the regulatory text, while the agencies indicate that “harm” should be understood more narrowly as conduct directly and intentionally directed at particular animals. This shift moves ESA implementation away from a habitat-centered conception of injury and toward a more individual-centered conception of prohibited conduct.
The Legal Background
Section 9 of the ESA generally prohibits the “take” of endangered wildlife. Congress defined “take” broadly to include actions such as harassing, harming, pursuing, hunting, shooting, wounding, killing, trapping, capturing, or collecting a listed species. For decades, FWS and NMFS regulations construed “harm” to reach an act that actually kills or injures wildlife, including significant habitat modification or degradation that produces such injury by substantially impairing essential behavioral patterns.
That interpretation was not legally peripheral. In Babbitt v. Sweet Home Chapter of Communities for a Great Oregon, the Supreme Court upheld the habitat-modification component of the regulatory definition. The Court accepted that conduct may “harm” protected animals even if the actor does not physically strike, capture, or kill a particular animal, provided that habitat alteration causes the requisite injury. The 2026 rescission therefore departs from an interpretation that had been judicially sustained for roughly three decades.
What Does This Change?
The most precise description of the regulatory action is not that it redefines “harm,” but that it removes the existing definition. That distinction has practical and doctrinal consequences.
Under the former framework, habitat modification could constitute an unlawful take if it actually killed or injured listed wildlife through serious impairment of breeding, feeding, sheltering, or related essential behaviors.
Under the agencies’ new interpretive approach, indirect or unintended injury arising from habitat alteration is less likely to be treated as “harm,” especially where the activity is not aimed immediately and intentionally at particular animals.
“Harm” remains in the ESA’s statutory definition of take. What has disappeared is the agencies’ codified regulatory explanation of what that word encompasses.
The rule places greater weight on future enforcement decisions and litigation to determine the scope of “harm” in specific factual contexts.
The agencies characterize the change as an effort to adhere to what they view as the ESA’s “single, best meaning.” Critics contend that it substitutes a narrow intent-focused reading for the broader, causation-based approach previously recognized in Sweet Home.
Why Habitat Is Central
The policy stakes are high because habitat loss and fragmentation are central drivers of risk for many listed species. A prohibition limited principally to direct, intentional injury may fail to address harms produced by clearing forests, draining wetlands, grading coastal areas, constructing barriers, or fragmenting migration corridors—actions that can diminish survival and reproduction without visibly injuring an animal at the moment the work occurs.
This issue is especially acute for species dependent on large, connected, or specialized ecosystems. Examples include old-growth-dependent species such as the northern spotted owl, wide-ranging carnivores such as gray wolves and Canada lynx, and borderland species such as the ocelot. In each case, degradation or fragmentation of habitat may compromise population viability even when a developer or landowner does not intend to injure an individual member of the species.
Consider a project that clears nesting habitat during a season when no birds are visibly present. Under the former regulatory approach, the legal question could be whether the alteration actually impaired breeding or sheltering sufficiently to injure protected wildlife. Under the post-rescission framework, a court may instead confront a more difficult threshold question: whether indirect habitat-driven injury fits the statute’s unelaborated term “harm” at all.
Uncertainty, Institutions, and Litigation
The rescission also shifts institutional authority. Previously, regulated parties, conservation organizations, and courts could look to a settled regulatory definition that had survived Supreme Court review. Now, courts will likely play a larger role in determining how “harm” applies to habitat-altering activities, potentially on a case-by-case basis. Stanford legal commentary notes that litigation challenging the rule is already underway and warns that judicial resolution may take years.
This uncertainty has divergent implications. Landowners and developers may view the change as reducing regulatory exposure associated with otherwise lawful land-use activities. Conservation advocates, by contrast, may see it as weakening a central mechanism for preventing ecological injury before it culminates in direct mortality. The key analytical question is therefore not simply whether the ESA still prohibits take—it plainly does—but whether a statute designed to conserve species can function effectively if habitat destruction is treated as legally distinct from injury to the species that depend on that habitat.
The FWS lists the rescission as part of a broader set of ESA regulatory revisions, alongside changes involving threatened-species protections and critical-habitat procedures. The “harm” rule should thus be evaluated not in isolation, but as part of a wider recalibration of the relationship between species protection, habitat conservation, agency discretion, and private land use.
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