Future of Isle Royale's wolves and moose in jeopardy

| Dec. 27, 2011  |  

A wolf stands over a moose carcass on Isle Royale. Congressional budgets cuts could threaten funding of a 53-year-old study that examines the relationship between the two. / Photos by ROLF O. PETERSON

By Tina Lam

Detroit Free Press Staff Writer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A wolf pack roams Isle Royale. The number of wolf packs dropped from four in 2008 to just one now.

Moose on the island have suffered as temperatures warmed, causing them to become weak and threatening their population.

The lives of wolves and moose on Michigan's remote Isle Royale are always precarious, but they are more at risk now than they have been in decades, thanks to climate change and too few females.
And for the people who study them, funding is in peril.
Rolf Peterson, co-director of a study that has lasted for 53 years, said it is impossible to predict the future of the animals or the study. While wolves in Michigan are scheduled to come off the federal endangered species list in January, the study at Isle Royale is designed to examine the interactions between predators, the wolves, and their prey, moose, over long periods of time in a confined environment.
The study's annual reports read like a soap opera: There are dynasties, powerful men, surprising mate choices, mysterious interlopers and murders.

The wolves' numbers have dwindled to 16; the long-term average is around 24. The number of wolf packs dropped from four in 2008 to just one, now, along with some lone stragglers. The last time there was just one pack on the island was 40 years ago.
During the past decade, for unknown reasons, more male wolves have been born than females. As females dwindle, the population could be doomed. Scientists said they believe there are no more than two females among the wolves, down from 10 in 2009; two females died last year.

But there was a ray of hope in late August: Researchers spotted two wolf pups, a sign that one female reproduced. If one or more of the pups is female, that could help boost the population.
The wolves are showing signs of spinal deformities, which have increased during the past 15 years and may be linked to inbreeding.
Moose have suffered as temperatures have warmed, bringing more ticks, which weaken the moose by forcing them to scratch off their own fur on trees to try to get rid of the ticks. With less fur, they become weaker. Hot summers make it harder for female moose to ovulate.
"Climate change is very evident," said Peterson, who has measured temperatures on the island in different seasons, and said winter minimums now rarely hit zero.

Even though there is plenty of food for moose, there are about half as many moose as the long-term average, and their numbers are not rebounding as Peterson expected.
"It's unprecedented to have so few moose for so long," he said.
Old moose are the primary food for wolves, so as they die out, wolves face a food shortage.
Moose swam to the island more than 100 years ago, but the first wolves arrived in the late 1940s by walking across ice from the mainland. The delicate balance between the two species is the focus of the study, the longest prey-predator study on the planet.

The study began in 1958 at Michigan Technological University. Peterson, 62, has been part of it since 1970. Its funding comes mostly from the National Science Foundation, and looming congressional budget cuts could threaten or eliminate the study.
In addition to offering important research on wolves and moose, the study shows how climate change is affecting animals, provides information on population genetics that applies to other animals and even delves into arthritis that afflicts both moose and people.
Old moose get arthritis, like people do, Peterson said. While it might seem that there's no link between humans and moose, he said scientists are finding new information about arthritis from moose that could be useful in fighting it in humans.

The fact that Isle Royale is isolated gives scientists a way to study moose and wolves free of other influences. For example, moose in Minnesota are dying. The cause is suspected to be a worm they get from deer. But Isle Royale moose are dying, too, and there are no deer on the island, so researchers are studying whether the reason for the deaths could be climate change, not worms.
Peterson can't say whether the study will continue another year, much less another five decades, because of possible funding cuts. "It has nothing to do with our competence as scientists," he said.

If wolves die out, there will be a big policy question the National Park Service will have to decide -- should new wolves be brought in? Peterson's view is yes, because they keep moose in check, and otherwise the moose could overrun the island.
For now, Peterson and co-director John Vucetich are looking forward to next year's winter study to see what mysteries unfold. They've been surprised in the past and could be again by what happens.
"It's inherently unpredictable," Peterson said.

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