The Nebraska case is one of several across the country sparked by the success of New Mexico farming and ranching groups that challenged habitat protection for an endangered bird.

For years environmental groups won court decisions forcing the U.S. Fish and Wildlife Service to designate "critical habitat" for endangered species more quickly.

However, in 1998 the New Mexico Cattle Growers Association, the New Mexico Farm and Livestock Bureau and several other groups sued the U.S. Fish and Wildlife Service over a critical habitat designation for the southwestern willow flycatcher.

They argued that the federal government had not properly considered economic impacts. The Endangered Species Act (ESA) bars major changes to a creature's territory when water from federal irrigation projects, federal money or other federal actions are involved.

Last May, a panel of judges from the 10th U.S. Circuit Court of Appeals in Denver agreed with the New Mexico farmers and ranchers.

Karen Budd-Falen, a Wyoming attorney who handled the flycatcher case for the groups, said the Nebraska lawsuit will challenge the critical habitat for the piping plover on behalf of Nebraska farm groups.

"It certainly has created a storm of cases where people challenge critical habitat based on the failure of the Fish and Wildlife Service to follow their regulations," she said. "This is absolutely a national issue, not just a West phenomenon."

The ruling also changed the way the U.S. Fish and Wildlife Service designates a critical habitat.

"The recent decisions have forced us to recognize that the economic analysis we had been using needed to be changed," said agency spokesman Chris Tollefson in Washington, D.C.

The agency has voluntarily agreed in several cases to redo the economic analysis rather than fight in court.

In the flycatcher case, ranchers argued that their livelihoods could be threatened if they were forced to fence cattle out of certain areas, build new stock ponds or remove livestock from federal grazing allotments.

In California, a federal judge cited the willow flycatcher case in determining that the government must conduct a new economic analyses of critical habitat for the California gnatcatcher, a tiny coastal bird, and the San Diego fairy shrimp.

The changes have worried environmentalists.

"It's definitely an alarming trend," said Peter Galvin, a conservation biologist and co-founder of the Tucson-based Center for Biological Diversity. "We're very concerned that what industry is doing here is attempting to basically turn back the clock on wildlife protections."

The center, which has successfully fought to force critical habitat designations for many endangered species in the past, has "deployed a huge amount of resources" to intervene in the cases and hire its own economists, Galvin said.

The New Mexico Cattle Growers Association has filed two new lawsuits against the federal government since winning the flycatcher decision.

"It's disappointing the agency didn't just take the 10th Circuit case and go back and rethink their process," said executive secretary Caren Cowan. "We hope that the government will settle them and we won't have to litigate them all the way through."

The cases challenge critical habitat for the spikedace and loach minnow and the Arkansas River Shiner. The cases also involve plaintiffs from Arizona, Texas, Oklahoma and Kansas.