Disappearing wolves, flourishing moose on Isle Royale

ISLE ROYALE NATIONAL PARK — At Isle Royale National Park, the populations of wolves and moose are headed in different directions.

Researchers found just three wolves on the Lake Superior island near Thunder Bay last winter. At the same time, the moose population is on a steep increase, in part because fewer wolves are preying on them.

Now, the National Park Service is putting together a moose-wolf-vegetation management plan and wants public comment.

Related: Just 3 wolves remain on Isle Royale and researchers are pessimistic about their future

One of the primary concerns is about the island’s vegetation, given the larger number of moose.

The park service is sponsoring a series of public open houses to take comment on the plan, but also is taking comments on its website until Aug. 29.

An image of Isle RoyaleCourtesy: National Park Service

The meetings are July 27 in Houghton, July 28 at Rock Harbor on Isle Royale, July 29 in Grand Portage, Minnesota, and July 30 at Windigo on Isle Royale.

In a document describing the need for a plan, park service researchers say the continued population of wolves on the island is in doubt unless new wolves go there or they are transplanted.

Read the document here:

Isle Royale Moose_Wolf_Vegetation Plan EIS Public Scoping Newsletter

Alternatively, the moose population is now estimated to be about 1,250 animals.

In the past, moose have become so over-abundant that it caused over-browsing of vegetation and a subsequent decline in the moose population.

Researchers say that cycle occurred in times when wolves were both lean and plentiful.

But they suspect the magnitude of the fluctuation in moose will be greater with no wolves.

Park service managers also want the management plan to cover vegetation, given that moose prefer such plants as balsam fir in the winter. That fir may be on the decline, however, as a long-term warming trend favors temperate species of plants and trees.

Here is a description of the National Park Service’s explanation on the need for management plan:

“Moose have important effects on island vegetation, including forest cover, and wolves are the only moose predator on the island. The moose-wolf-vegetation food web is tightly coupled. Given that the wolf population at Isle Royale is very low and their longterm survival on the island is in question, the moose population is likely to increase in the short term (5-10 years), which could result in impacts to vegetation and forest cover because of over-browsing.”

E-mail John Tunison: jtunison@mlive.com and follow him on Twitter attwitter.com/johntunison

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