Fifty Years Of Wolf-Moose Research

In the late 1940s, a pack of wolves made the treacherous trip across 15 to 20 miles of frozen waters of Lake Superior to Isle Royale, located not far from the Canadian border. There they found a wilderness island safe from hunters and traffic and home to an abundant moose herd. The wolves settled in to a self-contained ecosystem where they were virtually the only predators and the moose were their primary prey.

Conditions on the island made an ideal laboratory for scientific study of the predator-prey relationship free from outside influences. In 1958, biologist Durward Allen launched the Isle Royale wolf-moose study, chronicling population fluctuations of both kinds of animals and observing wolf-moose interaction and environmental changes to help explain these fluctuations.

The study continues today under the leadership of Rolf Peterson and John Vucetich, population biologists at Michigan Tech’s School of Forest Resources and Environmental Science. They do aerial and ground observations in summer and winter, collect moose and wolf bones to analyze, and study vegetation, climate, air and water contaminants, and other environmental factors.

“Although wolves and moose are in the spotlight, this study has implications for understanding the broader components of an ecosystem,” said Peterson, who has headed the Isle Royale wolf-moose study since 1976.

The primary lesson learned from this long-running study is that wildlife systems are complex, unpredictable and dynamic by nature, and they are influenced by a large number of environmental factors, added Vucetich.

“The data collected in the Isle Royale study provide a historical perspective that is very different from isolated snapshots of 5- or 10-year periods,” he explained.

Collection of thousands of moose bones over decades, for example, enabled scientists to assess the levels of mercury and lead accumulation in bones prior to and after changes in clean air regulations.

Partners with the National Park Service and Michigan Tech in the celebration of the 50th anniversary of the Isle Royale wolf-moose study include the Isle Royale Institute, the Isle Royale Natural History Association, the International Wolf Center, the Michigan Department of Natural Resources, the U.S. Department of Agriculture Forest Service, the University of Minnesota-Duluth, Northland College, the Timber Wolf Alliance, the Wisconsin Department of Natural Resources, the Great Lakes Research and Education Center and Discovery World in Milwaukee.