DNR faces conundrum as beavers get busy on Belle Isle

As work crews dig and build on Belle Isle to revamp Lake Okonoka, another hard-working crew has been busy transforming that part of the island on the Detroit River as well — a colony of beavers.

The water-loving rodents have gnawed down at least three willow trees so far this month, in an area of the state park where a canal separates the Dossin Great Lakes Museum and Anna Scripps Whitcomb Conservatory.

"I'm just amazed how quickly they are able to do that work," said Detroit resident Michael Betzold, who said he rides his bike on Belle Isle most mornings.

"I just naively thought it took a long time for beavers to build their dams and get their wood for it. But I never saw any damage to those trees until they were completely destroyed."

It's a new development, said Ron Olson, the Michigan Department of Natural Resources' chief of Parks and Recreation.

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"We've been involved in Belle Isle since 2014, and there hasn't been any disruption, trees removed, any problems at all," he said.

Olson suspects the beavers previously lived at the far east end of Lake Okonoka, and the draining of the lake for renovation work may be a factor in why their activity is now showing up in more visible areas of the park.

It raises a bit of a conundrum.

"It's good to know the habitat, the water quality and everything else is sufficient to support beavers," Olson said. "That, I think, is a very positive thing."

But people like those willow trees lining waterways along parts of the island, too.

"I hate to see the trees go down, but I don't want to see any beavers killed," Betzold said. "And I understand that it's a good thing environmentally that they are back."

Beavers are herbivores that eat wood as part of their diet — and willow trees are among their favorites. They'll also use branches to dam waterways and to build their lodges. They don't hibernate through winters, but store branches at the lodge to eat the underbark for meals until spring.

Amateur wildlife photographer Melissa McLeod has trekked inland on Belle Isle to shoot photos of beavers at their lodges.

"They've been cutting down trees for the three years I've been watching them," she said.

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"They kind of walled off the canal (for the Lake Okonoka project), so they can't get to the lake where the smaller trees are," McLeod said. "So, just for the last week or so, they've been eating these more scenic, more visible trees."

DNR staff have installed wire fencing around some of the still-standing willows in the area where the beavers have been busy. DNR wildlife experts are being consulted on how to proceed with the animals themselves, Olson said — whether relocating them might be required, or whether the wire-wrapped trees will send them elsewhere in search of an easier meal.

It comes with the territory of having a lush, natural, forested island habitat, McLeod said.

"I don't agree that the island is just for people; it's for animals, too," she said.

Contact Keith Matheny: (313) 222-5021 or kmatheny@freepress.com. Follow on Twitter @keithmatheny.