The Biden administration announced plans on Friday to reverse policies implemented under President Donald Trump that weakened the Endangered Species Act, a half-century-old law credited with the recovery of the bald eagle, humpback whale, grizzly bear and dozens of other species.

The U.S. Fish and Wildlife Service and the National Marine Fisheries Service under President Biden are moving to undo much of the Trump administration’s work that altered the ways habitats of plants and animals on the verge of extinction are kept from total collapse.

The decision to bolster the federal government’s power to protect vanishing plants and animals comes as the world finds itself in the midst of what United Nations scientists say is a worldwide decline in biodiversity that threatens to erode food systems and other key parts of the global economy.

Martha Williams, principal deputy director at the Fish and Wildlife Service, said in a statement that her agency will work with both industry and Native American tribes “to not only protect and recover America’s imperiled wildlife but to ensure cornerstone laws like the Endangered Species Act are helping us meet 21st century challenges.”

Led by former interior secretary David Bernhardt, an expert on the Endangered Species Act, the Trump administration whittled down several long-standing protections for imperiled plants and animals following complaints from loggers, ranchers and other business interests.

For example, the previous administration allowed wildlife officials to take the economic cost of conserving species into account when deciding whether to put a plant or animal on the endangered species list — a move many environmentalists claimed violated both the letter and spirit of the law.

Trump officials also made it easier to remove protections for threatened species, such as the American burying beetle, which once scurried nearly everywhere east of the Rockies but now lives in only a few parts of the country and is further threatened by climate change. Under Trump, the Fish and Wildlife Service weakened protections for the beetle at the behest of oil and gas drillers who must work around the imperiled insect.

The U.S. Fish and Wildlife Service and the National Marine Fisheries Service say they will revise or rescind those rules.

David Henkin, a senior attorney at Earthjustice, which sued the Trump administration over the changes, said the Biden administration’s announcement is “excellent news for critically endangered species.”

“As long as they do it quickly,” he added, “we can avoid bad on-the-ground consequences.”

Rep. Raúl M. Grijalva (D-Ariz.), chair of the House Natural Resources Committee, called the announcement “a good start,” urging the Biden administration to update the regulation in a way that safeguards species threatened by rising temperatures.

“With climate change bearing down on us and no serious doubt remaining about the consequences of inaction, we should take this opportunity to update all federal standards as thoroughly as possible to prevent habitat destruction and biodiversity loss before it’s too late,” he said in a statement.

Republicans criticized the move for potentially undermining any push to rebuild roads, bridges and other infrastructure if opposed by environmentalists.

“Many of the reforms put in place under President Trump were born out of input from local communities and the men and women most affected by the policies created in Washington,” said Rep. Bruce Westerman (Ark.), the top Republican on the House panel. “Yet by reinstating burdensome regulations, this administration has once again opened the door for environmental groups to weaponize the ESA and use it to delay critical projects across the country.”

Jonathan Wood, a research fellow at the Property and Environment Research Center, a free-market think tank focused on environmental issues, cautioned that restrictions on how habitat can be developed by humans “aren’t always better for recovering species.”

“The law’s punitive approach does little to encourage landowners to provide or restore habitat for imperiled species,” he said, adding that the Endangered Species Act “too often makes rare species liabilities that landowners and states understandably want to avoid.”

Historically hailed as a success by the World Wildlife Fund and other conservation groups, the Endangered Species Act has helped keep the vast majority — 99 percent — of protected wildlife from extinction.

Yet many supposedly protected species are still far from thriving. A new study by the Woods Hole Oceanographic Institution this week, for instance, found that something isn’t right with the North Atlantic right whale.

Although the animal is listed as endangered and protected from harvest, it’s still impacted by deadly contact with humans through boat strikes and becoming entangled in fishing nets. Not all those incidents are lethal, but, according to research published in Current Biology, it has led to a startling finding. Right whales are getting smaller.

“We find that entanglements in fishing gear are associated with shorter whales, and that body lengths have been decreasing since 1981,” the study says. “Arrested growth may lead to reduced reproductive success and increased probability of lethal gear entanglements.”

The researchers used aerial photogrammetry data dating back to the early 2000s to measure whales observed for the study, taking 202 measurements of 129 individuals. Based on the findings, the authors determined that a whale born in 2019 is expected to reach a maximum length that’s one meter shorter than a whale born in 1981, a 7 percent decline.

To further protect some of the hundreds of thousands of plants and animals near extinction, Biden campaigned on a plan to conserve 30 percent of the nation’s land and waters by the end of the decade.

So far, though, his administration has offered few details on how it will achieve that ambitious goal, while weathering criticism from Republican lawmakers who call the plan an example of government overreach.

And plenty of other Trump moves, including a decision to deny protections for the monarch butterfly along the West Coast, still remain on the books.

“It’s disappearing,” said Noah Greenwald, endangered species director at the Center for Biological Diversity. “It may be gone before 2024.”