09 Aug The Lost Wolves of Isle Royale National Park
Gray wolves have lived in Michigan’s Isle Royale National Park for almost 70 years. Should we intervene to save them, or let them “wink out”?
On a wild, remote island in Lake Superior, gray wolves have lived and thrived for almost 70 years. In the island’s forests — which make up the majority of Michigan’s Isle Royale National Park — a wolf population that grew to almost 50 individuals once contributed to a biodiverse, healthy ecosystem.
Today, however, it is believed that only two wolves remain. The survivors belong to the Chippewa Harbor pack. They are siblings who share a mother and, in addition, the female wolf is the daughter of the male.
An era that began with the wolves’ arrival on Isle Royale in the late 1940s, and that continued through the formation of three packs with memberships typically in the range of 18 to 27 animals, is coming to a close.
Some blame climate change for the loss. Others say it is just the natural order of things for species to come and go in a particular area. But whatever the cause, the question for the future health of the island and the national park is: Should we intervene to keep wolves on Isle Royale?
Climate change culminates a long-standing study
Surrounded by Lake Superior, Isle Royale National Park is rugged, isolated and far from the sights and sounds of civilization. ©Joe Ross, flickr
In 1949, three gray wolves from Canada walked 15 miles across the ice of Lake Superior to Isle Royale, a 45-mile-long, up-to-nine-miles-wide island located off Minnesota’s North Shore. The island’s appeal for the wolves probably had a lot to do with a resident population of moose, descended from forebears that, it is thought, swam to the island around 1900.
In 1958, what would become the longest continuous study of a predator-prey system in the world — called the Wolves and Moose of Isle Royale Project — began on the island. By 1980, it was estimated that the wolf population there had grown to 50 individuals. By 2009, however, scientists could verify only 24 wolves living on the island. That number dwindled to nine in February 2014 — a figure that at the time was the second lowest total for the island ever recorded. Now, in 2017, we believe there are only two wolves left.
Most scientists believe that climate change — and the resulting lack of gene diversity available to the wolves — is the culprit. In the past, during most winters, the Lake Superior waters between mainland Ontario, Canada, and Isle Royale would freeze over, allowing new wolves to find the island. But beginning in the 1970s, rising temperatures caused ice bridges to form only about once a decade, which means that the chance of new wolves making it to the island to supplement the gene pool steadily decreased. What’s resulted is the most extreme case of inbreeding ever documented in a wolf population.
Without wolves, moose numbers on Isle Royale could double within four years. ©Ray Dumas, flickr
Intervene to interrupt a wiping out of wolves?
Losing its wolves also means that Isle Royale National Park will most likely lose its forests and current ecosystem. Moose love to browse balsam fir. Unchecked by predators, they quickly decimate all the balsam fir trees around them — damaging the forest’s ability to regenerate. That causes change that cascades down through the food chain. According to a report issued by the School of Forest Resources and Environmental Science at Michigan Technological University on March 31, 2017, the balsam fir forest had been recovering to its healthiest state in a century or more until the wolves went into their current decline.
Once, in an average year on Isle Royale, wolves killed about 10 percent of the moose; but as wolf numbers have declined, the moose population has skyrocketed: from 1,300 in the winter of 2015–2016 to 1,600 in the winter of 2016–2017. Because of high moose reproduction rates, mild winters, an abundance of food and now virtually no pressure from wolves, the moose numbers could double to record high levels within three or four years. Eventually, though, the moose will run out of food, they’ll starve, and their population will crash.
As for beavers, a secondary food source for the island’s wolves, the study found that the “population has continued to increase, a pattern initiated when the wolf population collapsed in 2010–2012. There were almost 300 active beaver sites in 2016, a threefold increase in the past half decade.” While the precise results of a beaver surge on the island are not yet known, we are certain that beavers reshape landscapes; especially in isolated systems such as Isle Royale. It is also probable that in the end, they will starve, too.
Wolves keep the moose population in a healthy balance, protecting the island’s forests and ecosystem. ©Rolf Peterson
The National Park Service has proposed transplanting up to 30 wolves on Isle Royale, a precedent-setting idea that acknowledges that extraordinary steps need to be taken if a healthy balance of predator and prey in this Lake Superior wilderness is to be restored. By fall 2017, the service hopes to reach a final decision on what to do about introducing the wolves to the landscape. It’s possible that a new wolf population could be in place by the end of 2018.
Sense for standing back
The recommendation is a remarkable switch for the National Park Service, which has traditionally adhered to a hands-off policy in managing wilderness. Some conservationists have been critical, since the strategy would violate the intent of the 1964 Wilderness Act, under which almost the entire island of Isle Royale is protected. The rationale for those who are against bringing new wolves in is that the natural order on Earth is for species to continually “wink in” and “wink out.” Human manipulation of species’ numbers in a landscape, they say, can be a slippery slope. In 1900, caribou and lynx were the largest animals on Isle Royale. Both eventually disappeared, along with smaller species, such as coyotes and spruce grouse. Wolves and moose are relative newcomers here, along with tricolored bats and tree frogs. Unlike in Yellowstone National Park, wolves aren’t native to Isle Royale. Therefore, performing a genetic rescue by introducing wolves would break new ground.
Those who don’t wish to see the Isle Royale wolves wink out counter that the Wilderness Act was anchored in the idea that letting nature take care of itself was the surest way to preserve a natural system, a concept that may now be outdated. Today, there is a growing realization that sometimes climate change and other factors are so overwhelming that nature is not enough. And, the isolation of Isle Royale makes it, in some ways, even more fragile than many other parks and wilderness areas.
Places where wolves are free to roam are rare on the planet. Perhaps Isle Royale should remain one of them. ©Ray Dumas, flickr
Research by Michael Nelson of Oregon State University shows overwhelming public support for having wolves on Isle Royale, even if that involves intervention. According to his analysis, 86 percent of public comments solicited by the National Park Service agree that wolves should be present in that national park. Half of those commentators cited maintaining ecosystem health as a key reason.
The loss of wolves in Isle Royale National Park saddens those who have visited the island, those who wish to, and those who never will, but are concerned nonetheless.
I think that’s because places where wolves roam free are mighty rare on this planet.
Do you think that because of human-caused climate change, we need to step in and bring new wolves to Isle Royale? Can nature be expected to repair itself today, with unnatural, anthropogenic climate change?
Here’s to your adventures, in whatever corner of the world you find them,
Candy
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