By Jim Lynch / Detroit News

Gray wolves are in danger of disappearing from Michigan’s Isle Royale National Park, while these predators in the rest of the Upper Peninsula have experienced a major resurgence.

The situation is coming to a head on both the island and the mainland, where the state’s Natural Resources Commission is scheduled to meet Thursday and expected to decide whether a mid-November wolf hunt for the Upper Peninsula, but not Isle Royale, will proceed.

Lansing-based Keep Michigan Wolves Protected this week announced a new referendum challenge to the state law passed in May that gave the commission that authority. The latest referendum effort comes too late to halt this year’s possible wolf hunt — aimed at decreasing threats to western U.P. residents and domestic pets — but could bar future hunts.

“Michiganders deserve to have their voices heard on the wolf issue, and we hope they’ll have the opportunity to vote on two ballot measures next year to do that,” said Jill Fritz, director of Keep Michigan Wolves Protected.

But the May law’s sponsor, state Sen. Tom Casperson, R-Escanaba, said he will be relentless in ensuring “the people of the Upper Peninsula are heard as they overwhelmingly have pleaded for management efforts, including hunting, to help address problems caused by a growing wolf population in their backyards.”

Michigan’s wolf population has made a major comeback, growing from three wolves in 1989 to more than 650 today. By contrast, wolves on the Lake Superior island declined from a high of 50 in 1980 to eight recorded this year.

In past decades, freezing temperatures on Lake Superior would create a frozen bridge between the island and the Minnesota and Ontario mainland roughly eight out of every 10 years. It allowed wolves to cross the frozen water and maintain and bolster their population on the isolated island.

Warmer weather now leads the ice bridge to form about once every 15 years, leading to the wolves’ decline.

Seeking a solution

The situation would be worse if not for the Old Gray Man, as researchers and park officials call him — a wolf that wandered across the ice from the mainland to Isle Royale in 1997. After years of inbreeding among the island population, this single wolf’s infusion of new genes helped bolster the numbers for a short time and showed researchers how weak the island wolves had become.

The pattern of decline hit a new low this past winter.

“This last year was the first in more than four decades of monitoring that we haven’t been able to detect any evidence of reproduction,” said John Vucetich, a population biologist at Michigan Technological University, whose research focuses on the Isle Royale wolf population.

The National Park Service, which oversees Isle Royale, is continuing to gather evidence before deciding how to deal with the island’s remaining wolves. It faces three options:

■Do nothing.

■Wait and see if they go extinct on the island, and then reintroduce the animals.

■Introduce two to four new wolves in an attempt to stimulate population growth.

David Mech, a wildlife biologist with the U.S. Geological Survey who is considered an expert on wolves, favors an approach he calls “watchful waiting.” It would allow the animals to disappear from Isle Royale if that’s how things play out.

The drastic fall in wolf numbers matches an earlier decline in the island’s population of moose — a main source of food for the wolves. In addition, the number of wolves dipped to 12 on several occasions before rising to healthy levels again.

“For 25 years, we’ve been concerned about these wolves, and each time I’ve counseled that it’s better to wait and see what happens,” Mech said. “I still think that’s the right approach.”

But Vucetich wants to introduce new wolves. Unlike prior declines in Isle Royale’s wolf population, he said, this one is being intensified by human influence, namely climate change.

The loss of regular ice bridges to the island has intensified inbreeding. Despite a large number of moose available for food, the annual percentage killed by wolves has dropped from a typical 10 percent to 2 percent last year. It does not bode well for the future.

“It could pretty easily be another four years before the wolves go extinct,” Vucetich said.

A Park Service decision could come in October.

“Right now we’re in fact-finding mode,” said Phyllis Green, Isle Royale park superintendent. “We’re very concerned about the population numbers, but we also want to make sure we make the right decision for the future.”

Debate on hunting

The U.P. wolf question has generated more controversy. Gray wolves were on the U.S. Fish and Wildlife Service’s endangered species list for almost four decades before being delisted in early 2012. During that span, the population grew to a high mark of nearly 700.

In December, Gov. Rick Snyder signed Public Act 520 that allowed for wolf hunting and trapping — as urged by many state residents to curb the growing wolf population.

It kick-started Keep Michigan Wolves Protected to collect more than 250,000 signatures for a referendum on the wolf hunt, which effectively would have put the hunt on hold. Michigan legislators countered with a new law that authorized the Natural Resources Commission to designate species as game animals and keep the hunt alive.

“These new laws reaffirm the people’s desire for Michigan’s wildlife to be managed using scientific, objective standards,” legislative sponsor Casperson said in May, adding the laws ensure “the preservation of our way of life in Michigan.”

Fritz and members of Keep Michigan Wolves Protected contend residents are on their side. “It’s only fair,” Fritz said, “to allow citizens to weigh in on this important question of wildlife policy.”