A federal judge in Montana ruled against the U.S. Forest Service last week, ordering the agency to further examine the impact of domestic sheep grazing on wild bighorn sheep.

Montana Fish Wildlife and Parks (MFWP) began reintroducing bighorn sheep into the Greenhorn Mountains in 2001. They were prevalent in the region a century ago, but the population declined precipitously since the 1930s. In 2002, the Forest Service, the Bureau of Land Management and  MFWP entered into a memo of understanding allowing  “permitees” to graze domestic sheep in the same area. The memo detailed strategies to avoid contact between the sheep populations. In subsequent years, the bighorn sheep population failed to increase and the Forest Service issued a Revised Forest Plan in 2009 addressing the issue.

In this case, GALLATIN WILDLIFE ASSOCIATION v. UNITED STATES FOREST SERVICE, the plaintiffs, a wildlife organization, argued the presence of domestic sheep grazing prevents bighorn sheep herds from growing to a viable size in the area, mainly due to the spread of disease. The plaintiffs further argued that domestic sheep grazing harms their members’ aesthetic and recreational interests and that only by enjoining domestic sheep grazing in the area will the bighorn sheep population thrive. Critically, plaintiff’s contended that the 2009 Revised Forest Plan “failed to include measures to provide habitat for bighorn sheep in their historic range,” and did not consider studies finding that domestic sheep could harm bighorn sheep.

Per the Bozeman Daily Chronicle, U.S. District Court Judge Brian Morris ruled that the Forest Service “failed to disclose agreements between the agency, sheep ranchers and the state government in their forest plan.” Importantly, the Forest Service did not complete enough environmental analysis on domestic sheep grazing allotments in the area at issue.

The court stopped short of prohibiting domestic sheep grazing until the Forestry Service revises its analysis. Glenn Hockett, president of the Gallatin Wildlife Association, told the Chronicle that the Forest Service will have to provide more analysis and “bring the best available science to the table” regarding the conflict between bighorn and domestic sheep.

A copy of the court’s order is available here.