The U.S. Fish and Wildlife Service must conduct another assessment of grizzly bear survival, this time related to domestic sheep in southwest Montana, according to a settlement reached Monday.

U.S. District Court Judge Lynn Winmill of Boise, Idaho, approved a settlement between five conservation groups headed by the Cottonwood Environmental Law Firm and five U.S. agencies.

The settlement requires the U.S. Fish and Wildlife Service to research a new assessment of the effects of the U.S. Sheep Experiment Station on grizzly bear populations.

The assessment must be completed by June 1. In the meantime, the government is not permitted to graze sheep on the summer pastures in Montana prior to July 1.

The U.S. Sheep Experiment Station is a U.S. Department of Agriculture facility with property on either side of the Montana-Idaho border along the Centennial Mountains east of West Yellowstone.

On the Montana side, more than 16,000 acres of Agricultural Research Service land is used for summer grazing and rangeland research.

But that land also sits in the primary conservation area for grizzly bears around Yellowstone National Park.

Grizzly bears regularly travel out of the park and cross the sheep station property to reach the Centennial Mountains.

The grizzly bear was categorized as threatened in 1975. The Endangered Species Act requires that agencies properly assess the effects of federal projects, such as grazing or logging, on the survival of listed species.

The USFWS conducted such an assessment, published on Nov. 8, 2011, which concluded that the sheep station would not jeopardize grizzly bears although there had been several past conflicts.

That assessment was questioned when a grizzly-bear collar started emitting a death signal from a location on the sheep station property in September 2012.

Biologists had attached the collar to a 4-year-old male bear in the Centennial Mountains just a few weeks before.

According to investigation reports, Grizzly Bear Study Team biologists found the collar under a log in the East Fork of Spring Creek. The leather collar had been cut off.

The biologists later found a shotgun shell casing near where a large sheep herd had been grazed. The bear was never found and no charges were brought.

The USFWS sent a letter to the Sheep Station asking that sheep not be grazed on the Centennial Mountain pastures, but the sheep station refused.

As a result, John Meyer of the Cottonwood Law Firm sued the agencies in May 2013 and later amended the lawsuit, claiming the continued operation of the station violated the ESA.

The Gallatin Wildlife Association joined the lawsuit, questioning the need for a sheep research station so remote from universities and towns.

“I question the economics,” said GWA president Glenn Hockett. “Why are we perpetuating this research in the Centennial Mountains, in one of the most remote parts of the ecosystem, when all the other sheep grazing allotments around there have been retired? It's not a good idea to perpetuate the conflict.”