(CN) – A federal judge handed a victory to conservationists Wednesday, finding the Trump administration’s plan to boost energy development, mining and construction in greater sage grouse habitat should be halted while the two sides argue the merits.

U.S. District Court Judge B. Lynn Winmill ruled the Bureau of Land Management (BLM) failed to properly analyze the effects of its plan to facilitate more economic activity on more than 51 million acres of sage grouse habitat across seven western states.

“When the BLM substantially reduces protections for sage grouse contrary to the best science and the concerns of other agencies, there must be some analysis and justification – a hard look – in the NEPA documents,” Winmill, a Bill Clinton appointee in the District of Idaho, wrote. “It is likely that plaintiffs will prevail on their claim that this hard look was not done with respect to all six EISs.”

NEPA, or the National Environmental Protection Act, requires government agencies to conduct environmental analysis when undertaking any project or land management plan on federally managed lands. An EIS is government shorthand for environmental impact statement.

In the present instance, the BLM has attempted to split up sage grouse management into regions, giving the states more autonomy to make decisions that reflect the priorities and needs in each locality. Seven states are affected by the plan – Colorado, Idaho, Utah, Wyoming, Nevada, Oregon and California.

The effort to regionalize plans for sage grouse protection has never been favored by environmental organizations like plaintiffs Western Watersheds Projects, Advocates for the West and the Center for Biological Diversity.

Regionalization predates the Trump administration and prompted a lawsuit in 2015. However, after Trump became president he has prioritized economic development on public lands in the American West, causing the conservationists to pause the previous lawsuit and file another once then-Interior Secretary Ryan Zinke finalized plans for the greater sage grouse.

David Bernhardt replaced Zinke as secretary and is named in the lawsuit.

“The Bureau of Land Management deliberately undermined protections for the sage grouse, then had the audacity to claim these rollbacks would not impact the species,” said Sarah Stellberg, an attorney with Advocates for the West representing the plaintiffs. “The law demands more. This injunction is critical to protecting the sagebrush steppe and this icon of the American West.”

The greater sage grouse, a bird endemic to a wide swath of the sagebrush country spanning much of the American West, has long been at the center of a fight between developers, livestock managers, mining enterprises and energy development companies on one side and environmentalists and wildlife advocates on the other.

While the bird once roamed the western sagebrush landscape by the millions, the species has seen a significant population decline: Scientists estimate only 200,000 to 500,000 birds remain.

The bird uses sagebrush-grassland or juniper sagebrush-grassland, which proliferates at lower elevations throughout roughly 300 million acres of the American West, as a vital feeding ground. Scientists say residential development, natural resource extraction and cattle grazing in the bird’s natural habitat has led to its precipitous population decline in recent decades.

Environmental groups petitioned the U.S. Department of Fish and Wildlife to list the bird as endangered. Advocates for the various economic interests dependent on the land said such a listing would cripple several industries, much like the timber industry in the West was hobbled after the northern spotted owl was listed as endangered due to loss of habitat.

President Barack Obama’s Interior secretary Sally Jewell led a five-year effort that culminated in a compromise to provide protections for the sage grouse while stopping short of listing it as endangered – a deal all affected states and interested parties signed off on.

Within weeks of Trump’s inauguration, however, his administration said the deal would be revisited.

The ruling does not mean the conservationists have prevailed in their lawsuit; it only blocks the Trump administration from moving forward with its plans while the lawsuit is pending. Nevertheless, the ruling is a setback for the administration, which argues additional development will not unduly hurt the population of the iconic bird.