Earlier this year, researchers on Isle Royale made a grim discovery when completing their annual wolf count: The island’s wolf population totaled just three animals, down from the previous year’s count of nine and continuing a dwindling trend seen over the past several years (the wolf population peaked at 50 in 1979). Meanwhile, over the same time frame, the moose population has been growing at a rate of 22 percent per year.
The shifting face of Isle Royale’s wilderness is a result of climate change: Warmer winters mean fewer years when ice bridges allow mainland wolves to cross over and keep the island wolves’ gene pool diverse and therefore healthy. As the wolves have declined, the moose population has exploded—and when moose numbers grow too large, they can cause irreparable damage to the forest around them, which would cause a cascade of other environmental changes. An Isle Royale without wolves, biologists say, will become a completely different wilderness.
But the question about whether or not to repopulate the island by introducing new wolves is a thorny one. National Park Service experts say they must be thorough with this decision because it will set a precedent for other national parks that face climate-change-driven local extinctions—but wolf proponents criticize the park service for dragging its heels on a time-sensitive issue. “Every year we wait, we just increase the chances of having irreparable harm to the forest,” says John Vucetich, a Michigan Tech ecology professor who has been studying the wolves of Isle Royale for two decades. “This is very likely the last gasp for wolves on the island.”