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A photo of a moose

The U has conducted studies on moose in Isle Royale National Park since 1985.

If you give a moose a forest...

By Pauline Oo

From eNews, March 10, 2005

At more than a thousand pounds and six feet tall at the shoulders, the twig-chomping moose is a formidable diner in Michigan's Isle Royale National Park, an island in Lake Superior off the shore from Grand Portage, Minnesota.

Since 1985, the University has maintained a database of information on moose in Minnesota and the way this animal's eating habits can change its own food supply. The ongoing Isle Royale study, funded by the National Science Foundation and conducted through the U's Natural Resources Research Institute (NRRI) in Duluth, helps park service and forest managers better understand one of their wildlife inhabitants, and therefore, more appropriately plan for the future. The research also complements other moose population studies throughout the world.

"It's taken us almost 20 years to get to this point," says NRRI scientist John Pastor, who has supervised four graduate students on moose-related projects. "It might surprise people, but this is a fairly new idea--that wild animals have an effect on their natural environment, and not always a positive effect."

Minnesota, like its Michigan neighbor, is one of the few U.S. states that have these majestic creatures; Alaska usually comes to mind when one thinks of moose. There are about 4,600 moose in Minnesota, mainly in the northwestern and northeastern parts of the state, according to the Minnesota Department of Natural Resources. They are the state's largest wild animal, and they're the largest member of the deer family--weighing as much as four or five full-grown deer.

"It might surprise people, but this is a fairly new idea--that wild animals have an effect on their natural environment, and not always a positive effect," says NRRI scientist John Pastor.

NRRI's moose and vegetation studies take place on Isle Royale's 134,000 acres of wilderness. Last year, NRRI scientist Ron Moen found that moose munching--as much as 25 pounds of brush a day--can change the composition of the island's forest and also eat away potential fuel for fires.

"The park service wanted to know how the moose are affecting the vegetation on the island, especially if they're altering it to the point where a forest fire would be less likely to occur," explains Moen. Last winter's low precipitation makes this information pertinent, particularly if a hot, dry summer lies ahead.

Moen's study involved growing a simulated forest with a computer modeling program developed by his colleague Pastor and using a computer fire modeling program developed by the U.S. Forest Service to simulate how quickly fires spread given a variety of circumstances.

"We 'planted' about 20 tree species that are found on the island, then ran simulations with moose browsing that corresponds to low and high moose populations," says Moen. Their virtual creations confirmed their suspicions that in the older boreal forests, moose browsing had little effect except on the underlying layers of vegetation, but moose foraging alters forest growth in areas that have burned and are regrowing.

Moose trivia

A moose can store more than 100 pounds of food in its stomach.

Moose have weak eyesight and have actually mistaken cars for potential mates.

Moose can run 35 mph and easily swim 10 miles without stopping.

Moose are mostly active at night but can be seen any time of the day. Most sightings occur at dusk or dawn.

(And according to a Google search result, it's illegal to feed alcoholic beverages to a moose in Fairbanks, Alaska.)

Source: Minnesota DNR and the USDA Forest Service

So is it beneficial or harmful if moose make fires less likely?

The fires that have occurred on the island in the past 50 years have not spread into large wildfires because of moose browsing, says Moen. Unwittingly, though, the moose may actually have made their lives more difficult. Moen adds that uncontrolled fires would allow more new saplings of aspen to grow, and thus, provide more food for the moose. (Young aspen branches and leaves are a moose favorite.)

U graduate student Nathan DeJager is currently expanding on Moen and Pastor's research and will be at Isle Royale this summer. He plans to look at what happens to a plant after a moose takes a bite. (When you clip a hedge, it grows thicker. But when a moose clips a twig, will two twigs grow in its place?)

"When I'm done with this study, I can apply what I've learned to other ecosystems or wildlife populations," says the future conservation biologist.

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