Brent Fenty, executive director of the Oregon Natural Desert Association, said the decision will lead to long-term improvements for managing environmentally sensitive streams.

PORTLAND — A federal judge has ruled that grazing on public land in the Malheur National Forest has led to degradation of steelhead streams that the U.S. Forest Service failed to protect.

Conservation groups said the ruling by U.S. District Judge Ancer Haggerty showed the Forest Service grazing plan allowed livestock to damage steelhead habitat over nearly half a million acres along more than 300 miles of streams in the John Day River Basin in eastern Oregon.

Livestock can damage stream banks and muddy the clear, cool water needed for steelhead, a Pacific Northwest native trout listed as threatened under the Endangered Species Act.

Brent Fenty, executive director of the Oregon Natural Desert Association, said the decision will lead to long-term improvements for managing environmentally sensitive streams.

"We want to see steelhead recover in the John Day so they can once again be a central, social, cultural and economic asset," Fenty said.

But a rancher and spokesman for other ranchers in the area said the ruling was also a win for them because it showed the agency must tell them when they need to move their cattle away from critical stream banks.

"The key is when you get to the point the cows need to be moved, they need to be moved," Ken Holliday said. "It's really the Forest Service's job to do monitoring and be watching everything. They're the ones with all the science on their side."

A number of ranchers had intervened in the lawsuit to argue the Forest Service violated the Endangered Species Act by arbitrarily limiting grazing on public land in the Malheur.

The judge said in the ruling that damage done to stream banks in 2007 and 2008 was "particularly deplorable" and noted "this court has repeatedly found the grazing program to be insufficiently protective of listed fish species."

The current plan could have better protected fish if it had been enforced more effectively, the judge said.

A Forest Service spokesman in Portland referred questions to the agency's headquarters in Washington, D.C., but officials were not available for comment after hours.

David Becker, an attorney for the Oregon Natural Desert Association, said the ruling will help guide the next biological opinion, or plan for steelhead protection, expected next spring.

He praised Haggerty for bringing ranchers, environmentalists and federal agencies together as he considered the case, including earlier rulings on grazing permits for the 13 allotments covered by the current biological opinion issued in 2007.

"Maybe the agreement that the judge had us work on for this current season is a harbinger of something we can sit down together and talk about," Becker said.