A conservation group claims the U.S. Forest Service failed to consider all of the impacts of livestock grazing in its adoption of a management plan for the 1.1 million-acre Bighorn National Forest, according to a petition filed last week in federal court in Cheyenne.

The Boise, Idaho-based Western Watersheds Project also wants the Wyoming U.S. District Court to conduct a judicial review of the Forest Service's implementation of the management plans for 32,000 acres of grazing allotments in Piney Creek, Little Piney and Willow Park, according to the petition for review of the agency's action.

Both plans, the group said, "are arbitrary, capricious, an abuse of discretion, and/or not in accordance with law… ."

A Forest Service spokesman could not be reached for comment on Wednesday.

The Western Watersheds Project, which also has an office in Pinedale, had challenged and unsuccessfully appealed the Forest Service's 2004 draft environmental impact statement, along with the 2005 forest plan and the final environmental impact statement regarding the impact of various levels of grazing in the forest, according to the petition filed by Elizabeth Richards of Advocates for the West.

Richards could not be reached for comment on Wednesday.

It questioned the Forest Service's analyses of whether the forest lands could sustain grazing; the lack of grazing alternatives; and the effects of grazing on wildlife, riparian areas, water quality and soils.

Likewise, the Western Watersheds Project challenged and unsuccessfully appealed the final environmental assessment and the Piney Creek allotments decision notice earlier this year, according to the petition.

Regarding the Piney Creek notice, it challenged the study itself, monitoring requirements, lack of alternatives, and "failure to take a hard look at the effects of grazing."

So it filed the petition asking the federal court to reverse and set aside the Bighorn forest plan and the Piney Creek Allotment decision notice, claiming the Forest Service violated the National Environmental Policy Act and the National Forest Management Act.

The Western Watersheds Project and other environmental organizations have protested other aspects of the forest plan, including the amount of logging allowed and roadless protection.

Craig Yancey, district ranger for the Tongue River District of the Bighorn National Forest, was not available for comment on Wednesday. However, Yancey wrote that the environmental impacts were not significant in the May 7 decision notice about the Piney Creek, Little Piney and Willow Park allotment management plans.

Allowing grazing in these allotments will not hurt conditions of rangeland vegetation and the watershed, nor will it hurt water quality, soils, public health or wildlife habitat, he wrote.

Allowing grazing also complies with the National Forest Management Act, the Endangered Species Act and the National Historic Preservation Act, Yancey wrote.

"I find that this alternative best meets the combined needs of the affected environmental resources, while providing a sustainable level of livestock grazing for the permittees and the local communities," Yancey wrote.

Reach Tom Morton at (307) 266-0592, or at Tom.Morton@trib.com.