By Paresh Dave, Los Angeles Times

On an icy island wilderness near the tip of Minnesota, a female gray wolf’s demise has added to the debate about whether authorities should try to save the wolves of Isle Royale National Park.

Once, wolves could regularly move on and off the island along ice bridges to find fresh mates. Now, researchers say, climate change has made ice bridges rare on Lake Superior, and the increasingly isolated wolf population has grown weak through inbreeding. The death of the wolf nicknamed Isabelle, who had apparently crossed an ice bridge in search of a mate, reduced the known population to nine.

The researchers have called on the federal government to interfere with a wilderness area, a drastic break from tradition that they say is forced by climate change. They want the National Park Service to import fertile wolves from robust neighboring populations.

“To preserve a healthy ecosystem with climate change, we at times are going to have to intervene, and that’s a hard thing to wrap our heads around,” said Michael Nelson, an Oregon State University professor who specializes in environmental ethics and philosophy.

That proposal is controversial, and the National Park Service has not decided what to do.

The carcass of 5-year-old Isabelle, one of three potentially fertile Isle Royale wolves, was found Feb. 8 and announced late last month. An initial necropsy failed to determine a cause of death.

At least, researchers say, three of the island’s surviving wolves are less than a year old — a welcome development after a worrisome year without any pups.

Isle Royale is a rare place where predator and prey, wolves and moose, can fend for themselves without interfering predation by humans or bears. The matchup has been closely tracked since 1959. The park gets fewer visitors in a year than Yosemite National Park sees in two days, but thanks in part to scientists, Isle Royale has more repeat visitors than anywhere else.

Moose migrated to Isle Royale around World War I, and wolves after World War II. Two decades ago, the wolf population dipped from 50 to about a dozen. Researchers won approval to install tracking devices on some of the wolves and draw their blood.

Researchers discovered that the wolves had been ravaged by a disease brought to the island by visitors’ pet dogs. But the population rebounded, reaching 30 before falling again about five years ago.

Now, climate change is further stressing the wolves. Once, solid ice bridges to Minnesota happened seven out of 10 winters. Now, it’s more like once a decade, including in 2008 and two weeks this winter.

By 2040, ice bridges won’t exist, said John Vucetich, a Michigan Tech University population biologist who studies the wolves and moose of Isle Royale.

Inbreeding has led to genetic abnormalities, including deformed backs. Vucetich and his colleagues said that could be remedied by importing wolves from abundant packs in Minnesota or Ontario, Canada.

If the National Park Service decides to let nature take its course and the wolves die out, researchers warn, the moose population could boom and destroy the park’s ecosystem.

Vucetich said that he, Nelson, ecologist Rolf Peterson and others who say man should intervene have faced several critics.

One group insists on a hands-off policy toward wilderness areas, regardless of the consequences. They worry that intervening in Isle Royale would open the floodgates nationwide. And researchers such as the U.S. Geological Survey’s Dave Mech say they would lose the ability to study the island’s small gene pool if more wolves were introduced.

“We couldn’t continue to validly assess what goes on from here on out if we intervene,” Mech said. About 20 years ago, for example, researchers learned more about the wolves’ behavior when a wolf that immigrated to the island considerably changed the makeup of the population. “All the offspring for the next several years had his genes,” Mech said.

Vucetich says he prefers the activist approach because “there’s some things we can resist and hang on to and not let climate change take away.”

He says the cost of protection — moving some wolves to the island — is low and the benefit — preservation of the status quo despite climate change — is great. “Genetic rescues” have been successful, including with Florida’s panthers.

Phyllis Green, Isle Royale’s park superintendent, says officials are summarizing the more than 1,000 public and expert comments they’ve gathered in the last two years. She expects to release a report in late spring.

“We’re going to take our time and make the most right decision we can,” Green said. “Try as we might as humans to predict what’s going to happen, the more we know, sometimes the clearer the path — but sometimes it’s still a trade-off.”

Bob Hallinen/Anchorage Daily News/MCT