RENO, Nev. (AP) — A federal judge has blocked a Nevada project that would expand livestock grazing across 400 squares miles (1,036 square kilometers) of some of the highest priority sage-grouse habitat in the West and accused the government of deliberately misleading the public by underestimating damage the cattle could do to the land.

The ruling comes as scientists continue to document dramatic declines in greater sage-grouse populations across 11 western states — down 65% since 1986 and 37% since 2002, according to a new report by the U.S. Geological Survey.

Its numbers have shrunk to less than a quarter of what they were a half century ago, the USGS said Tuesday. If current trends continue, there’s only a 50% chance most of their remaining breeding grounds known as “leks” will still be productive in 60 years, it said.

Citing concerns about grouse, U.S. administrative judge Harvey Sweitzer sided with conservationists in Nevada and suspended approval of new grazing permits for a swath of rangeland larger than Rhode Island. It stretches to Utah and includes a ranch once owned by Bing Crosby.

The senior judge at the Interior Department’s Office of Hearings and Appeals in Salt Lake City ruled March 19 the Bureau of Land Management failed to adequately examine potential harm to the grouse as required by the National Environmental Policy Act.

An administrative judge since 1970, when President Nixon signed the act into law, Sweitzer's decision could have ramifications for several permits approved across the West in the final months of the Trump administration under a 2017 initiative dubbed “Outcome-Based Grazing.”

Then-Interior Secretary Ryan Zinke said it loosened restrictions on ranchers to provide more flexibility to meet long-term rangeland health goals. Critics called it a “public land grab.”

“Instead of living up to its promise to conserve, enhance and restore sage-grouse habitat, BLM embraced habitat-destroying livestock grazing actions guaranteed to drive down bird numbers,” said Katie Fite, public lands director for WildLands Defense, which won the stay of the permits pending administrative appeal.

She said Sweitzer's decision is a “well-justified rebuke to BLM’s industry-biased grazing program that goes to great lengths to circle the wagons around livestock interests at the expense of wildlife, biodiversity, watersheds and myriad public uses."

Interior Department press secretary Tyler Cherry declined comment on the administrative ruling in an email Wednesday to The Associated Press.

But the department said in a statement Tuesday the decline of sage grouse documented by USGS reflects the overall loss of sagebrush habitat over decades from a variety of forces ranging from wildfires to energy development.

“The Interior Department is reviewing actions the Trump administration took to undermine carefully constructed land management plans to help conserve sagebrush habitat,” spokeswoman Melissa Schwartz said.

Nevada's Winecup-Gamble ranch was among 11 designated as demonstration projects in 2018 under the “Outcome-Based” initiative along with ranches in Oregon, Colorado, Idaho, Montana and Wyoming.

Sweitzer agreed with WildLands Defense’s argument the grazing levels approved for Winecup-Gamble in December are substantially higher than the average number of cattle that actually grazed there the past decade. The stay he ordered is akin to a temporary injunction in U.S. district court.

He said the agency ignored rangeland health assessments its own experts conducted in June when they determined the allotments “are not currently meeting the seasonal habitat needs of sage-grouse.”

USGS says the latest study is the most expansive ever on the declining status of the hen-sized bird, which is considered an indicator species for the overall health of sagebrush-related ecosystems from the Rocky Mountains to the Sierra.

The Nevada project covers 1,460 square miles (3,781 square kilometers) of public and private land, including 860 square miles (2,227 square kilometers) of federal land with priority grouse habitat. More than one-third of those U.S. lands are considered sage-grouse strongholds with the highest densities of grouse and other criteria key to the species' survival.

Sweitzer said the misrepresentations in the bureau's environmental assessment stem from the baseline it used to calculate increases or decreases in cattle numbers permitted under various alternatives.

The agency’s comparisons are based on maximum allowable levels established in earlier allotments, sometimes decades ago, he said. Instead, the baseline should be the average actual use the previous 10 years.

As a result, he said, the 30% reduction the agency cites in what it portrayed as a grazing-reduction alternative “is illusory.”

Likewise, the bureau never addressed the effects of the real increase anticipated under the “Outcome-Based” alternative it adopted, he said. “In fact, the EA goes farther than silence on the subject and actively misleads the public.”

Environmentalists said the new USGS study highlights the urgency of addressing loss of grouse habitat regionwide.

“We cannot ignore this alarm bell,” said David Willms of the National Wildlife Federation in Denver. “This report shows that much more needs to be done to restore sagebrush habitat so that sage grouse populations recover and that all wildlife that lives in this ecosystem thrives.”