A chronology of some events in the history of Isle Royale
1 billion years ago - The bedrock supporting Isle Royale was formed. These rocks, among the oldest in the world, are
exposed and visible at many places on Isle Royale’s shorelines and ridge tops.
8,000 years ago - Isle Royale emerged from Lake Superior, after the glaciers retreat. Evidence of this period includes beach lines on trail to Feldtmann campground, glacial striations, and drumlins on the interior of western Isle Royale.
3,000 years ago - Native Americans mined copper on Isle Royale and traded it throughout eastern and central North America.
150 years ago - Europeans began mining, and later fishing on Isle Royale.
c. 1900 - Moose arrive for the first time in Isle Royale’s history. The first moose may have arrived by swimming fifteen miles from Canada. In the absence of wolves, the lives of Isle Royale moose were inextricably linked to forest growth, moose ticks, and climate.
1929 & 1930 - Adolph Murie makes the first scientific observations of Isle Royale moose.
1931 - Congress authorizes Isle Royale to become a national park "to conserve a prime example of North Woods Wilderness."
c. 1950 –Wolves were extirpated from nearly all of the lower 48 states. Wolves walked to Isle Royale on an ice bridge from Canada. The lives of Isle Royale moose have never since been the same.
1958 - Durward Allen began studying the wolves and moose of Isle Royale.
2008 – Wolves, moose, and researchers have been watching each other for 50 years.
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Isle Royale is isolated. The island is separated from the rest of the world by more than 24 kilometers (15 miles) of icy Lake Superior waters. This isolation fosters conditions favorable for studying nature in several ways.
First, relatively few species have colonized Isle Royale. Isle Royale is inhabited by only about one third of the mammalian species that inhabit the nearby mainland. Some of the species missing from Isle Royale include porcupine, coyote, white-tailed deer, black bear, bobcat, fisher, red-backed vole, short-tailed shrew, and chipmunk. Of course, wolves and moose are present. But moose have only been present since about 1900, and wolves since about 1950.
On Isle Royale wolves are the only predator of moose, and moose are nearly the only prey for wolves. (About 10% of a wolf's diet is comprised of beaver and snowshoe hare.) Moreover, humans do not harvest wolves or moose. The wolves and moose of Isle Royale essentially represent a single-prey-single-predator system. This relative simplicity is not typical of terrestrial ecosystems. Because ecologists are interested in how species interact, Isle Royale is well suited for research because its paucity of species translates into a simpler ecosystem that we hope is easier to understand.
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If Isle Royale were smaller than it is, it would be too small to support a wolf population.
If Isle Royale were larger than it is, it would be too large to effectively study the moose population.
If Isle Royale were further from the mainland than it is, wolves and moose may never have made it to Isle Royale.
If Isle Royale were closer to the mainland than it is, other species which are not on Isle Royale, such as coyotes, deer, and bear, might have made it to Isle Royale. Studying species interactions becomes increasingly difficult with increasing species diversity.
Isle Royale is not too small, not too large, not too far, and not too close.
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Islands have always been special places to ecologists for reasons like these. Other islands have also been sites of important ecological revelation: Darwin's Finches of the Galapagos islands, the fruit flies of Hawaii, the foxes of the Channel Islands (California), the lizards of the Caribbean Islands, and many others. Many of the unique features of islands that are so important to ecologists are described by the theories of island biogeogrphy.
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Copyright © John A. Vucetich — All rights reserved
Aerial view of Chickenbone Lake from the southwest.
Aerial view of Isle Royale’s northeastern most end.
Isle Royale’s simplified wolf food chain (left) compared to Yellowstone’s more complex wolf food web (right).
For more on island biogeography and great ecological research that takes place on islands:
Weiner, J. 1995. The Beak of the Finch: A Story of Evolution in Our Time. Vintage
Quammen, D. 1997 Song of the Dodo: Island Biogeography in an Age of Extinction. Scribner
National Academy of Sciences. 2004. Evolution in Hawaii: A Supplement to Teaching About Evolution and the Nature of Science. National Academy Press