The Trump administration is believed to be making a run at weakening the Endangered Species Act/NPS file of endangered Florida panther

The Trump administration has initiated steps to redefine what it means to "harm" a threatened or endangered species, a move that could jeopardize the effectiveness of the Endangered Species Act (ESA), according to the Center for Biological Diversity.

Exactly what the new definition would look like isn't clear, as a filing placed Monday in Office of Information and Regulatory Affairs within the Office of Budget and Management did not contain specific language.

However, Noah Greenwald, the Center's codirector of endangered species, fears the worst.

Greenwald said refining the term is the "first step toward stripping habitat protections from rare plants and animals headed toward extinction."

“Weakening the definition of harm would cut the heart out of the Endangered Species Act and be a death sentence for plants and animals on the brink of extinction,” Greenwald said.  “The Trump administration has been systematically killing protections for our air, water, wildlife and climate like a vicious cancer. The malignant greed driving these policies threatens to greatly increase destruction of the natural world and turbocharge the extinction crisis. We’ll keep fighting for each and every one of these plants and animals.”

The Endangered Species Act prohibits “take” of endangered species by people, government entities, and corporations. Congress defined “take” broadly to include actions that “harass, harm, pursue, hunt, shoot, wound, kill, trap, capture or collect” species. The U.S. Fish and Wildlife Service has defined “harm” to include “significant habitat modification or degradation.”

According to the Center,  "habitat destruction is the primary cause of extinction, so the federal definition of harm has been pivotal to protecting and recovering endangered species. It was upheld in the 1995 U.S. Supreme Court case Babbit v. Sweet Home. From spotted owls to Florida panthers, including habitat destruction in the prohibition on 'take' has been critical to saving plants and animals from extinction. It’s a key difference between the federal Endangered Species Act and almost all state endangered species laws."

“Unless habitat destruction is prohibited, spotted owls, sea turtles, salmon and so many more animals and plants won’t have a chance,” said Greenwald. “Humanity’s survival depends on biodiversity and no one voted to fast-track extinction. This is a five-alarm fire.”

Project 2025, the conservative blueprint that seems to be guiding the Trump administration in many areas, calls for weakening ESA definitions for critical habitat and critical habitat exclusions, something President Donald Trump did during his first term. It also calls for resurrecting a move back in 2020 during the first Trump administration to weaken the Migratory Bird Act by allowing unintentional killings of birds.

Across the National Park System, how critical habitat for threatened and endangered species is determined is key to survival of listed species. Species that rely on habitat in and around national parks that could be impacted range from the Greater Yellowstone Ecosystem grizzly bears, which in 2019 regained threatened status after a federal judge said the U.S. Fish and Wildlife Service erred in delisting the bears, to Kemp's ridley sea turtles, the smallest of sea turtles and which are considered critically endangered.