Listen to today's Environment Report.

This year’s Winter Study of the wolves and moose of Isle Royale found that there are still just two wolves hanging out on the island.

Rolf Peterson is a research professor at Michigan Tech. He says this winter, he and his team got a much better look at the wolves.

“They’re a father and daughter, and they’re also half siblings. Any offspring they would have would be heavily inbred and not likely to survive. We did observe that the female is rejecting any advances from her father,” he says.

The researchers estimate that there are now more than 1,600 moose on the island and without wolves to eat them, the moose population could double in the next three to four years. Peterson says that the moose population’s sustainability depends a lot on the weather.

“Severe winter weathers are when, those are the times they’re challenged most and they’re short on food and they die of starvation. So the population, if it continues to grow for several more years, will certainly be up in the region where they could die off catastrophically during severe winters," he says.

The National Park Service has wrapped up a public comment period on the draft environmental impact statement on its proposal on how to manage wolves on Isle Royale.

There are four alternatives: one is to do nothing. The other three involve different options for introducing wolves.

The option the Park Service prefers is to introduce 20 to 30 wolves over three to five years.

It’s a complicated question because most of Isle Royale is designated as wilderness.

“Certainly under wilderness law, and policy, letting nature take its course is certainly a strong driver if you will,” says Phyllis Green, the park superintendent for Isle Royale National Park.

“However, even in wilderness areas, we have done species restoration when we felt that the changes caused by man have been appropriate. But what makes this complicated and more complicated is the fact of the isolation of the island itself,” she says.

That’s because with climate change, there are fewer ice bridges forming from the mainland to the island. That’s how new wolves have gotten to Isle Royale in the past.

Green says they’re in discussions with Minnesota, Michigan and Ontario. Those are all places they could take wolves from, to bring to the island. She says they’d want to introduce wolves that know how to hunt moose.

Researcher Rolf Peterson thinks the plan will work. He says if the Park Service decides to bring in new wolves, one thing to think about will be where to place the new wolves on the island.

“If you took wolves from different groups, you might want to space them as much as you could away from each other, just because they’re all trying to figure out the new landscape and establish territory, and you know, they won’t all get along necessarily," he says. "But there’s a limit to how much you can manage that sort of thing. You know, the wolves have to figure a lot of that out on their own.”

The Park Service is expected to issue a final decision on introducing wolves this fall.