BOZEMAN, MONT. -- As Yellowstone's grizzly bears crawl into their dens for the winter, one thing that will not rest is the controversy about whether enough is being done to protect their future.

At least 200 grizzlies roam Yellowstone National Park and adjacent national forest lands, and they have been declared a threatened species under the Endangered Species Act, requiring the federal government to approve a plan for their recovery.

A weeks-old recovery plan proposed by the U.S. Fish and Wildlife Service has been panned by conservationists who assert that the federal agency, by using 1975 population levels, when bears were most threatened, has set its sights too low in establishing target populations for grizzlies.

"The recovery plan seems to go against the grain of the Endangered Species Act. It sets targets for marginal populations," said Michael Scott of the Wilderness Society.

Chris Servheen, grizzly bear coordinator for the Fish and Wildlife Service, said the bears have shown remarkable recovery since 1975. The number of grizzly mothers with cubs was at an all-time high during the past summer, and the number of grizzlies being spotted in the Yellowstone back country also is higher than ever, he said.

While the number of sightings has made Servheen and others optimistic about the bears' future, the Yellowstone-area creatures are years away from being taken off the endangered species list.

Four grizzlies, three of them reproducing females, were shot this fall by elk hunters who claimed the bears threatened to charge at them. Because grizzlies have low reproductive rates, specialists say that each reproducing female is vital to the population.

The government's recovery goals call for having no more than two man-caused deaths among females and no more than seven grizzly deaths a year in the Yellowstone area. So far this year, eight grizzlies have died at the hands of man in the areas, and the trend has alarmed many bear watchers, including Dick Knight, head of the interagency Grizzly Bear Study Team. "If this continues, I think we're talking about delaying recovery," said Knight. "I'm not as optimistic as I was."

Knight criticized hunters who shot bears, saying that unprovoked attacks by bears are rare. "Hunting is a sport and a privilege, and people should know what the rules are. They should be able to recognize that if a bear stands up, it's not attacking you," he said.

The number of bear deaths has been used by conservationists as an example of the tenuity of the grizzlies' future. They argue that in the Yellowstone ecosystem, the recovery zone for bears should be expanded.

Inside the recovery zone, which includes all of Yellowstone and some of the Forest Service land surrounding the park, bears would take precedence in cases where there were conflicts between their activities and those of humans. Outside the zone, bears would be tolerated.

Knight said the recovery zone lines were drawn as a political compromise and seek a balance between protecting the bear and minimizing conflicts between people and bears in developed areas.

Conservationists say the many grizzlies living outside the recovery zone are threatened by developments in the region ranging from vacation homes to gold mines. Ed Lewis, of the Greater Yellowstone Coalition, said oil and gas wells, timber harvests and mines are proposed for grizzly habitat, and he accused the Forest Service of routinely approving such projects without considering the overall effect on bear numbers.

Grizzlies once ranged from the Arctic Circle to central Mexico. Abundant today in Alaska and parts of Canada, the bears now live in only two locations in the lower 48 states -- Yellowstone and Glacier National Park in northern Montana, where at least 440 grizzlies are likely to get off the endangered species list sooner than the 200 or so at Yellowstone.

Grizzly experts say that over the course of six years the Yellowstone population needs to have an average of 15 female grizzlies with cubs in order to be considered unthreatened.

Scott said the target numbers are so low that the grizzlies might never have a robust population in Yellowstone's ecosystem.