Ranchers in Wyoming greeted new federal grazing regulations with pleasure Wednesday, while conservationists called them a public lands giveaway.

In fact, one environmental group filed a lawsuit seeking to block the rules, saying they violate several federal laws.

First proposed in December 2003, the regulations would increase collaboration between the Bureau of Land Management and ranchers whose livestock graze on 160 million acres of the nation's public lands. The BLM announced the final grazing rules Wednesday, saying they will go into effect next month.

The rules would allow livestock owners to share costs and ownership of range improvements and would give some ranchers additional water rights. The rules would also lessen some public input on decisions affecting public rangelands to make the permitting process more efficient.

Jim Magagna, executive vice president of the Wyoming Stock Growers Association, said joint ownership of range improvements will allow ranchers to retain some of their investment.

"Every range improvement out there has a multiple-use benefit," Magagna said. "Wildlife have benefited from water development ranchers have put out there."

But Jon Marvel of the Western Watersheds Project said the joint-ownership provision is "designed to ensure rancher control over the use of these lands, and the public will be cut out."

Marvel's group on Wednesday filed suit on Wednesday in U.S. District Court in Boise, Idaho, asking for an immediate injunction to block the new rules. And Bobby McEnaney, a legislative advocate at the Natural Resources Defense Council, said his group and other organizations are planning to file an additional lawsuit to stop the rules from going into effect.