Import wolves to Michigan's Isle Royale 'as soon as possible,' says biologist

These three wolves are the last three native wolves living on Isle Royale, researchers say. Courtesy of Michigan Technological University.

By Garret Ellison
on September 03, 2015

HOUGHTON, MI — As the National Park Service mulls what, if anything, should be done to save the meager wolf population on Isle Royale, a leading environmental science researcher says the best way to tame the exploding moose population and protect island vegetation is to begin importing wolves. Only three wolves remain on the Lake Superior island park and experts say those animals are inbred and weak. Without intervention, the island's native population wolf may go extinct. The moose population, on the other hand, is estimated to be about 1,250 and climbing.

"It's important that action be taken sooner rather than later," said John Vucetich, a Michigan Tech University biologist who studies the wildlife of Isle Royale, an island covering 206 square miles in the northwest portion of Lake Superior.

Meanwhile, Democratic U.S. Sens. Gary Peters and Debbie Stabenow are trying to speed things up by urging the park service to complete a management plan to save the wolves by next July, a deadline that's unlikely to be met.

The senator is "concerned because researchers have said it's possible the wolves won't survive the next couple of winters," said Allison Green, Peters' press secretary.

In August, Isle Royale Superintendent Phyllis Green told Michigan Radio that an environmental impact study on the problem could be finished by 2017, a timeframe she characterized as swifter than usual. The Park Service has indicated it doesn't plan to import new wolves in the immediate future.
Vucetich thinks the impact study process should have begun years ago.

"The park took about four years to decide if they would embark on the decision-making process that would take another two years, at least," he said.

During that time, three wolves on the island fell into an old 19th century Pittsburgh and Isle Royale Co. mine pit and drowned in 2012. Three wolves might not seem like many, but they represented about a 25 percent population loss for the island, said Vucetich.

In this summer of 2004 photo released by Michigan Tech University, a moose and its baby are shown on Isle Royale.Courtesy | John Vucetich

With the moose and wolf populations headed in opposite directions, the concern is how much of the island vegetation the ascendant moose herd will eat. The potential forest damage from over-browsing "can't easily be undone."

For most of the past half-century, Vucetich said wolves typically killed about 9 to 10 percent of the island moose each year. Over the past four years, that number has dropped to about 2 to 3 percent — the island's lowest recorded predation rates.

The population decline has been exacerbated by disease and the lack of new wolves reaching the island via the frozen lake during winter. Through the 1960s, the wolf population kept itself healthy by occasional immigrants from the mainland.

The frequency of ice bridge formation has dropped over the decades. On average, they form only once every eight to 10 years, Vucetich said.

There's no guarantee that any year an ice bridge forms — such as the past two harsh "Polar Vortex" winters that saw massive ice cover on the lakes — a wolf will cross to the island. Sometimes it only happens once per decade, he said.

The "frequency of ice bridges is expected to continue to decline because of climate warming," Vucetich said. "That's why this issue is really much bigger than just being about Isle Royale. It's an issue that will set precedent on how the National Park Service will make decisions about climate change."

Although some have suggested culling the moose herd on Isle Royale, Vucetich dismissed that as "not a reasonable option" because of the likely negative social response to government moose-killing and the logistical hurdles associated with killing about 150 animals a year each fall, when he said it would have to be done.

The time window for embarking on a kind of "genetic rescue" through bringing breeder wolves to the island has passed, he said. The three wolves, a middle-aged mating pair and a cub, are likely too few to make that option viable.

While opposition to importing wolves stems from a "hands-off" philosophy to human intervention in wilderness areas, he said that "when humans have mucked things up, it's absolutely in line with wilderness policy to mitigate those effects."

The best way to restore the island's wolf population is "bring wolves to Isle Royale as soon as possible."

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