HOUGHTON — About 120 people came to an open house Wednesday on potential options for responding to the collapse of the gray wolf population at Isle Royale National Park.
In its recently released environmental impact statement, the park outlined four potential responses: no action; the limited introduction of 20 to 30 wolves over a three- to-five-year period (the park’s preferred alternative); the immediate introduction of six to 15 wolves with supplementation as needed; or no immediate action, but with allowance for the introduction of wolves in the future based on moose population and other changes to the ecosystem.
Moose first came to Isle Royale about 1900. Wolves established a population on Isle Royale in the early 1940s and 1950s, crossing an ice bridge from the U.S. or Canadian mainland.
The decline in the wolf population — down to two as of 2016 — has led to the moose population rising to 1,300, though that is short of the 2,400 observed in 1995.
Left alone, the EIS states, the wolf population would likely die off without migration across an ice bridge, which have been less frequent in recent decades. The lack of predation on moose and beaver would lead to a steep decline in balsam fir and a decline in other tree species, leading the way to a more savannah-like spruce forests.
The park’s preferred option of immediate reintroduction of wolves would result in “substantial impacts to wilderness character” due to the human manipulation of the food chain. However, the plan said, the introduction of wolves would provide a check on the moose population, restoring the previous ecological balance with an apex predator.
The plan estimates the introduction of 20 to 30 wolves would reduce the moose population by 210 moose per year, reducing the amount of plant browse by moose by 12,371,545 pounds.
“Overall, restoring predator-prey interactions could result in long-term beneficial impacts to the moose population,” the EIS states. “This would be a significant change from current conditions, which consists of a likely population crash from a decrease in population health in the near future.”
One questioner asked how the long-running wolf-moose study was behind the preference for reintroducing wolves. Green said the study had raised visibility of the park, but that it wasn’t determining policy.
“We welcome research on the island, but there are probably very different research questions you will be asking as a result of these different alternatives … if we’re going to reset the island, if you will, then the research will be looked at and evaluated for what questions will we learn and what hypotheses we will be addressing in the future,” she said. “So research is always a component, but it’s not the driver for national forests.”
Another noted that caribou and lynx had a much longer history on the island before being killed off by human hunters in the pre-park days. Green said NPS policy is not to remove animals within range of their normal viability, and that wolves and moose have been the two most recent predominant species. The presence of wolves, as well as a warmer climate, limit the prospects for caribou in the park, she said.
“They’re not a large creature like a moose that can stomp on a wolf,” she said.
As lynx don’t have much impact on vegetation, they were not a focus of the recent study, Green said.
Green said any wolves would be relocated from the Lake Superior area. Costs will be determined in the next phase of the process, if one of the relocation options is picked. Green said the costs would be handled from a nation pool of NPS money for managing wildlife.
“They actually won’t come directly form the park budget. they will come from the money that the park services uses for management of species across the system,” she said. “It has minimal impact on our local budget, but it is a tradeoff nationally.”
Comments are being accepted during a 90-day period at parkplanning.nps.gov/isrowolves or by mail to Superintendent Phyllis Green, Isle Royale National Park, ISRO Wolves, 800 East Lakeshore Drive, Houghton, MI 49931-1896.