DENVER -- Federal wildlife managers have dramatically increased the amount of land they want to designate as critical habitat for the Canada lynx, a threatened species.

The proposed critical habitat zone now includes 7,885 square miles in northwest Wyoming, including parts of Park, Teton, Fremont, Sublette and Lincoln counties.

Wildlife advocates were cautious as they waited to see whether the proposal would stick, while some were upset no area in the southern Rockies was included.

The U.S. Fish and Wildlife Service said Thursday it wants to designate 42,753 square miles in six states that could come under tighter federal oversight as critical habitat. That's more than 20 times the 1,841 square miles in three states the agency designated in late 2006.

A final decision might not come until Feb. 15, 2009. Fish and Wildlife said it was accepting public comments on the proposal until April 28, 2008.

The agency reconsidered its earlier rulings about the lynx and seven other species after allegations that Julie MacDonald, a deputy assistant secretary of the interior, interfered in the decisions. She has resigned.

States where land would now be designated as critical lynx habitat are Maine, Minnesota, Idaho, Montana, Washington and Wyoming.

About 58 percent of the habitat is on federal land, 30 percent on private land, and the rest on state, tribal or other ownership, Fish and Wildlife said. In Wyoming, 98 percent of the critical habitat is on federal land.

Lynx have been confirmed in recent years in Yellowstone National Park and in the Bridger-Teton National Forest. Bridger-Teton officials say they already manage the forest with protection of lynx habitat in mind.

Colorado, where state wildlife officials have been reintroducing lynx, was not included. The Fish and Wildlife Service said it was uncertain whether Colorado's population would sustain itself.

In 2007 state biologists found no new kittens, down from 11 in 2006 and 50 in 2005. Lynx trapped in Canada were released in southwest Colorado beginning in 1999. Some of them have moved into the Medicine Bow National Forest in southern Wyoming.

Joshua Pollock, conservation director for Center for Native Ecosystems, said a critical habitat designation was crucial to lynx recovery in the southern Rockies.

"Their habitat continues to get logged, cut up by development. Lynx are run over on highways, accidentally trapped and shot. We need to see critical habitat taken seriously in the southern Rockies. Today's proposal is definitely a blow to that need," Pollock said.

Colorado Division of Wildlife spokesman Tyler Baskfield said the lynx already is considered a "species of concern" in Colorado, and populations of the long-haired mountain cat are closely monitored.

Michael Senatore, director of the biodiversity program of the Center for Biological Diversity, said it would take time to review the proposal but that it was a step in the right direction.

"What's unclear is whether this is sufficient," he said. "It looks like they have left out important areas. There's nothing in the southern Rockies. That's problematic given there are lynx there. It also looks like for the most part they have focused on what may be an overly narrow definition of 'occupied habitat."'

He was also concerned the proposal could change within the next year.

"If they exclude most of what they're proposing, it's not going to mean much for the lynx," Senatore said.

The 2006 designation of critical habitat for lynx was for Voyagers National Park in Minnesota, Glacier National Park in Montana and North Cascades National Park in Washington.