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By Keith Matheny
Isle Royale’s two remaining wolves should soon get some much-needed pack mates.
The National Park Service outlined Friday how it intends to bring six to eight wolves from the mainland to the more than 200-square-mile island that’s part of a national park in Lake Superior.
It’s part of a planned “genetic rescue” to restore the predator-prey balance on the island between wolves and moose. For the last three years, only two wolves have remained on Isle Royale, half-siblings who are also father and daughter. Their inability to produce surviving offspring has left the burgeoning moose herd virtually unchecked, leading to worries of large disruptions of the island’s eco-system from the voracious moose’s huge vegetation intake, and the potential for a large-scale die-off of moose if balance isn’t restored.
This 2017 photo provided by biologist Rolf Peterson of Michigan Technological University shows the last two surviving wolves at Isle Royale National Park in Michigan. The National Park Service plans to relocate additional wolves to the Lake Superior park in coming years to rebuild the predator species’ depleted population. (Rolf Peterson/Michigan Technological University via AP)
Four of the incoming wolves will be from northeast Minnesota, live-trapped on the Grand Portage Band of Chippewa Indians’ reservation, Park Service officials said. Two other wolves will come from Michigan’s Upper Peninsula. It’s the first phase of a three-year plan to bring 20 to 30 wolves from the mainland to Isle Royale. The incoming wolves will receive radio collars so officials can learn more about their predation, mating and other habits on the island, the Park Service said.
Wolves came to Isle Royale more than five decades ago by crossing a frozen Lake Superior in winter. The island’s wolf population once reached 50 wolves, and averaged 25 wolves over decades, before a population crash in recent years because of the physical and reproductive impacts of inbreeding. Changing weather patterns, leading to fewer and smaller ice-overs of Lake Superior, have meant fewer ice bridges between the island and mainland to potentially replenish the wolf population.
The remaining father-daughter pair have seen their pack die around them. They produced a pup one recent year, but it died within a year.
That has meant little to no predation on the island’s abundant moose — and, in turn, a moose population boom. The moose count from this past winter’s study was 1,475 — down from the 1,600 count the previous winter, though that could be attributable to a slight overestimation that season, Michigan Technological University wolf researcher John Vucetich told the Free Press in May.
“The bigger trend, for seven years now, is the moose population growing at 16 percent per year,” he said. “The moose population can double in four or five years at that rate. They have done so over the past four or five years, and will do so again if current trends continue.”
The Park Service this spring approved a final environmental impact statement for the genetic rescue of Isle Royale wolves. The move is not without controversy, as the service must balance two goals: leaving national parks as natural and undisturbed as possible and preventing damage to the ecological balance of the park.
The nonprofit National Parks Conservation Association, which works to protect and preserve national parks, endorsed the plan to bolster Isle Royale’s wolf population.
“While six wolves for this first phase may not be as many as people expected this year, we appreciate the multi-agency, science-based plan that we know to be thorough and diligent,” said Lynn McClure, senior regional director for the association. “And we support their efforts to ensure a success for the island, its ecosystem, the wildlife and all who visit this national park.”