ALBUQUERQUE, N.M. (AP) — An environmental group called on federal wildlife managers Wednesday to update a decades-old recovery plan for grizzly bears to ensure the animal’s return to the Grand Canyon and other areas of the West.

The Center for Biological Diversity, in a petition filed with the U.S. Fish and Wildlife Service, accused the agency of using a fragmented approach as it tries to recover the threatened species. Efforts are currently focused on a fraction of the bear’s historic range, but the petition identifies more than 171 square miles around the West that could provide suitable habitat.

Those areas include a forested region straddling the Arizona-New Mexico border, the Grand Canyon, the Sierra Nevada in California, and parts of Utah and Colorado.

The recovery plan for grizzlies dates back to 1993. The Center for Biological Diversity says the plan needs to consider recent research that questions the long-term viability of the current grizzly population.

“The science is clear that, if we’re serious about recovering grizzly bears, we need more populations around the West and more connections between them so they don’t fall prey to inbreeding and so they have a chance of adapting to a warming world,” said Noah Greenwald, director of the center’s endangered species program.

A spokesman with the Fish and Wildlife Service said Wednesday the agency had not yet received the petition. He did not comment on whether the agency had any existing plans to update the grizzly’s recovery plan.

The agency did state as part of a review of the bear’s status done in 2011 that the recovery plan was outdated and it needed to consider other areas as potential habitat.

According to the agency, an estimated 50,000 grizzlies roamed between the Pacific Ocean and Great Plains during the early 1800s. Their numbers were drastically reduced as more pioneers headed west. By 1975, when the bears were listed, only six of the 37 separate populations that were present just 50 years earlier remained.

There are five areas where grizzlies are found today, including the Yellowstone region and along the northern Continental Divide.

Federal wildlife managers have had mixed success in trying to reintroduce larger species, such as the gray wolf.

Greenwald acknowledged there would be some opposition to the grizzly, but he said there seemed to be more reverence surrounding the bear.

“The grizzly is the mascot of the University of Montana, and you drive around Montana and it’s grizzly this and grizzly that. And in California, they’re on the state flag. They’re just such an iconic animal,” he said.