IN THIS FEBRUARY 2012 FILE PHOTO provided by George Desort, two gray wolves walk in the Isle Royale National Park in Michigan. The national park’s wolf population has fallen to eight, lowest since the 1950s, and scientists are debating whether to do anything about it.
The gray wolf population has dropped steadily in recent years at Isle Royale, a rocky, heavily wooded archipelago in Lake Superior that is among the least visited national parks because of its remote location — a sixhour ferryboat ride from the Michigan mainland.
Eight wolves remained when the last count was taken last winter, the lowest since the 1950s, although a couple of pups are believed to have been born this year. They’ve averaged 23 over the years. Scientists believe inbreeding, disease and a temporary shortage of the moose on which the wolves feed are responsible for the drop-off.
The wolves and moose are subjects of the world’s longest-running study of a predator-prey relationship in a closed ecosystem, which raises a thorny question for scientists: Should they intervene to preserve the wolves or let nature take its course?
The issue is forcing park managers to make an uncomfortable choice between their traditional hands-off policy toward wildlife and ensuring that Isle Royale continues to have wolves, a point of pride and longtime drawing card for visitors.
The situation could set precedents for other parks, refuges and wilderness areas dealing with threats to iconic species as climate change alters the environment.
“This is going to help define what we think the word ‘conservation’ means during an era of tremendous global change,” said John Vucetich of Michigan Technological University.
Vucetich and fellow biologist Rolf Peterson, who lead the wolf-moose study, are lobbying park officials to bring a few mainland wolves to the island, where they could invigorate the gene pool.
Moose showed up on Isle Royale, which consists of one large island and hundreds of small ones, around the turn of the 20th century. It’s unknown whether they swam or people brought them. Wolves arrived in the late 1940s, probably by crossing an ice bridge from the Canadian shore 15 miles away. With Lake Superior’s winter ice cover shrinking, it’s considered unlikely other wolves will get that chance.
Wolves have become valuable to Isle Royale’s health by preventing a moose population explosion that would devastate the vegetation on which many animals depend, Vucetich and Peterson say. After slumping a few years ago, the moose have bounced back with the wolves’ decline and totaled nearly 1,000 in the latest census.
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