At Isle Royale National Park, where the island's wolf population has been in slow decay for years, park officials have announced plans to take a thorough look at options for preserving wolves on the landscape.
Chronic inbreeding appears to have impacted the health of the wolf population, which at last count numbered nine. There was hope that "ice bridges" that formed between the Lake Superior island and the Canadian mainland this past winter would enable wolves to arrive from Canada with new genes. But it appears that no new wolves reached the island, while one female left and was killed by a gunshot wound near Grand Portage National Monument in Minnesota.
Now, Isle Royale Superintendent Phyllis Green says her staff will conduct a comprehensive planning process through an environmental assessment that considers management of wolves, moose, and vegetation on the island.
Specificially, the park "will develop a management plan addressing the many complex factors that affect persistence of Isle Royale wolves and their role in the island ecosystem, including relationships with moose (their preferred prey), the condition of island vegetation, and the effects of ongoing climate change," a park release issued Wednesday said.
“Many people are waiting for us to bring new wolves to Isle Royale or to announce that we’re leaving their future gene pool up to wolves that may migrate from the north shore of Lake Superior when winters are cold enough for an ice bridge to the island,” Superintendent Green said. “This issue is bigger than only wolf genetics.”
“The plight of these nine wolves is a compelling story,” she continued, “but we are charged with a larger stewardship picture that considers all factors, including prey species, habitat, and climate change, which could, in a few generations, alter the food base that supports wildlife as we know it on Isle Royale.”
Isle Royale wolves have been in decline for more than a decade. For the past two years, park managers have discussed island and wolf management with wildlife managers and geneticists from across the United States and Canada and have received input during public meetings and from Native American tribes of the area.
While the park will not bring wolves from outside to Isle Royale in the near term, Superintendent Green said there is time to fully explore the consequences of such an action. If the island population of wolves declines to all males or all females and if the moose population grows to over-browse island vegetation, bringing wolves to the island remains an option, she said.
Isle Royale National Park lies in a transition zone between the northern hardwoods and boreal forests and some climate models predict the park’s landscape will change from cold-adapted boreal species to warm-adapted species.
“We need to monitor the island and share information about the changing ecosystem to ensure this remains a dynamic wilderness setting and that park visitors will have a wilderness experience for generations to come,” the superintendent said.
Severe weather events – including winter ice bridges – are linked to the changing climate, she said. There is still a chance of nature replenishing the gene pool as wolves are able to move to and from the island when ice bridges form.
The lives and the decline of genetic diversity in the wolves have been documented in a long-term ecosystem study of the predator-prey relationship between wolves and moose now in its 56th year. Superintendent Green said the park will continue to collaborate with Michigan Tech University scientists who conduct the study, and has also initiated a project with the U.S. Geological Survey to model the impacts moose have on park vegetation.
As park staff develops the new management plan and environmental analysis, they will continue to monitor the remaining wolves on the island. Scoping for the project is expected to begin in the fall. There were no wolves on Isle Royale when it was established as a national park in 1940. The first wolves likely arrived 65 years ago by walking over 18 miles of Lake Superior ice that connects the island to an area near the Minnesota-Ontario border.