The National Park Service released four gray wolves on Isle Royale in northwestern Lake Superior in October 2018 to start rebuilding the island’s severely inbred packs.
Three months later, a female from the foursome fled across Superior’s ice toward its home turf on the mainland 15 miles away. Was that wolf’s departure saying something about the NPS’s “genetic rescue” effort?
After all, one reason the NPS approved a five-year, $2 million plan to relocate 20 to 30 wolves to Isle Royale was because ice “bridges” to the Minnesota/Ontario shoreline have been rare and short-lived in recent years, possibly because of climate change. During the 1960s, stable ice formed most winters and lasted weeks to over a month. But from 1998 to 2011, a solid ice “bridge” formed only once in 2008. Bridges formed twice from 2013 to 2017, but lasted only days, not weeks.
With rare winter access to the mainland this century, Isle Royale’s wolves became genetically isolated. Without regular infusions of new blood, the island’s wolves became terminally inbred. Biologists believe that’s why the island’s wolf population shrunk to one unproductive male and female pair by 2018.
Biologist Rolf Peterson at Michigan Technological University reported high numbers of wolf pups dying at birth, and others born with dead eyes, fused toes and “a grab bag of oddities.” The researchers also reported 58% of Isle Royale’s wolves had various congenital spine defects, including 33% suffering a lumbosacral transitional vertebrae malformity, or LSTV. Therefore, Peterson and other biologists thought Isle Royale’s wolves would “blink out” without human intervention.
Wolves were first documented on Isle Royale in 1948. Their population peaked at 50 in 1980, but have averaged 22 since their arrival. Their primary food source on the island is moose, which arrived in the early 1910s. Biologists estimate Isle Royale’s moose numbers to be at least 1,300 in 2016, and growing 20% annually. They warn that moose could severely overbrowse the island’s aspens, birch, yew and balsam firs and might crash if wolves aren’t restored.
Rescue or Abandon?
All such predictions, forecasts and estimates have sparked scientific and philosophical debates about whether to rescue or abandon Isle Royale’s “famous” (some say “fabled”) wolf and moose populations. In fact, some folks question why anyone describes these large mammals as “famous” or “fabled,” given that both have far less history on the island than the humans debating their fate.
Timothy Cochrane, an NPS historian and anthropologist, notes that humans fished, hunted, trapped, logged and mined copper on the 9-by-45-mile island for at least 4,000 years before it became a national park in April 1940. Further, islands can’t support the wide varieties of species and large numbers of individuals found in nearby mainland habitats. It’s natural for species to appear, flourish and “wink out” on islands.
Neither wolves nor moose appear in Isle Royale’s prehistoric records, and no one knows for certain how they got there in the 1900s. It’s assumed they crossed 13 to 15 miles of ice from Minnesota or Ontario. But if reaching Isle Royale is all about ice bridges, why didn’t moose and wolves plant their flags there long before climate change hampered winter travel?
Unverifiable stories suggest humans brought moose to Isle Royale over 100 years ago when Minnesota was “shipping moose” many places. Cochrane also notes that World War II could have indirectly pushed wolves to the island while the region’s trappers fought in Europe. In the trappers’ absence, wolf numbers soared and dispersers stumbled onto Isle Royale by 1948.
Cochrane suggests, perhaps rhetorically, that if society wants to restore Isle Royale’s traditional predator-prey relationship, it’s more about lynx and woodland caribou, not wolves and moose. Caribou were last documented on Isle Royale in 1925 and lynx disappeared in the 1930s. Further, when folks suggest Isle Royale’s current restoration parallels the NPS restoring wolves to Yellowstone National Park in the mid-1990s, Cochrane notes differences: wolves had a history in Yellowstone, and humans caused their demise but then corrected their error.
“The Yellowstone equivalent would be to shoot off Isle Royale’s moose and wolves, and bring back lynx and caribou,” Cochrane told attendees in June 2013 at an Isle Royale discussion in Minneapolis. “I don’t think the public would want that, either.”
Should Nature Dictate?
Other scientists and wilderness advocates believe the NPS should let nature dictate the wolf’s fate. They note Isle Royale is a federally designated wilderness area, which requires it remain free of human intervention. In writing the 1964 Wilderness Act’s text, preservationist Howard Zahniser legally defined wilderness as places “where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.”
Opponents also argue that science would learn much by studying how Isle Royale’s birds, animals and plant communities respond to the wolf’s absence. Thomas Heberlein, a retired rural sociologist at the University of Wisconsin-Madison, conducted research in national parks and sat on the National Academies of Sciences Committee on Science in the National Parks. Heberlein said the NPS is taking the easy way out by restocking wolves. He refers to a letter he wrote May 10, 2013.
“Science should watch and wait, observe and measure, and let nature teach us lessons, rather than get in there to control and manipulate to ‘save’ nature,” Heberlein wrote. “Who knows what we might learn? Wisconsin, Minnesota, Ontario and Michigan’s Upper Peninsula all have wolves. Should wolves go extinct on Isle Royale, it might be an important control to compare wolf and wolf-less ecosystems. … It’s possible the ancestors of these wolves made a bad choice for sustainability by migrating to Isle Royale, and that nothing could be more natural than for that population to end. We can learn from that.”
Even so, Heberlein said he wasn’t surprised in June 2018 when the NPS issued its “Record of Decision” to restore the island’s wolves. When contacted for this article, Heberlein said: “The round-heeled NPS went backward capitulating to nonscientific sentiments from wolf researchers, just as I said they would six years ago.”
One such researcher is Mark Romanski, an NPS biologist and Isle Royale’s natural resources division chief. He acknowledges the critics and criticism, but defends the NPS’s decision.
“We involved as many stakeholders as possible, we listened to everyone, we addressed their concerns in our plans and based our decision on science,” Romanski said. “We supported wolf restoration because we need to restore a dynamic predator-prey relationship to keep moose in check. Our plan allows for natural ups and downs in populations and forest-browsing cycles, as opposed to severe booms and busts associated with no predators.”
Romanski said the NPS received about 4,500 public comments during its review process, including everything from petitions to form letters to grade-schoolers’ pleas to save the wolves. Reviewing and tabulating all those comments for this article wasn’t possible, but a sampling of the comments online suggest a 55-45 majority favoring wolf restoration.
Still, Romanski said NPS doesn’t set policy by referendum. “There’s a misconception that we take votes or count yays and nays. That’s not what we do,” he said. “We try to address the issues they raise with the best knowledge available to us.”
His work this spring includes talks with the Michigan Department of Natural Resources about possibly obtaining wolves from the Upper Peninsula, 55 miles south of Isle Royale. The NPS wants to establish two to four wolf packs on Isle Royale from a 20- to 30-wolf population. Romanski said he and other biologists from around Lake Superior are trying to get wolves with wide genetic diversity. He said the challenges don’t end there. For example, how will wolves from different regions get along or form packs when released into Isle Royale’s unfamiliar landscape?
Trap-and-transfer efforts are difficult with large mammals, especially in Northern climates and on the world’s largest inland lake. For instance, just after biologists moved those four wolves to Isle Royale in late October, Lake Superior’s famous November storms ended operations. Two months later, the federal government shut down for five weeks, which put the project in limbo.
Just as the shutdown ended Jan. 25, a polar vortex froze the waters between Isle Royale and the Minnesota/Ontario shoreline, and that female wolf headed homeward. Another wolf in the group also tried crossing, but its GPS collar showed it returned to Isle Royale, likely after encountering open water. Yet another wolf in that initial group, the only male, died on the island. Therefore, only two wolves from the October transfer, both females, remain.
Meanwhile, private donations in January bankrolled reintroduction efforts in lieu of federal funding. That enabled the NPS to move 11 more wolves to Isle Royale, raising wolf numbers to 15 as of March. Six of the wolves came from Ontario’s Michipicoten Island to the east in Lake Superior, and the others came from the mainland.
Romanski said the NPS has three years to get 20 to 30 wolves re-established on Isle Royale, and then two years to assess how they’re faring, and how wolf-predation rates on moose compare with historical rates. In 1966, researcher David Mech documented a 15- to 16-member wolf pack on Isle Royale killing one moose every three days in winter. Based on that rate, researchers estimate 30 wolves would kill about 210 moose annually, or 16 percent of a 1,300-moose herd.
Critics, however, remain skeptical that wolves can establish a self-sustaining population. After all, the original population teetered on extinction in 2018 after a 70-year run, so why would the current effort end differently? Opponents think the island’s wolves will require expensive, repetitious supplemental stockings.
They also note that if overbrowsing by moose is so ruinous, how did the island’s vegetation survive when moose populations boomed and crashed for four decades before wolves arrived in 1948? Isle Royale’s forests also bounced back from several 1800s infernos set by miners to reveal copper veins in the island’s bedrock.
Romanski concedes those points, but said the NPS’s wolf plan increases the likelihood of sustaining a healthy moose herd and forest ecosystem on Isle Royale. Further, the NPS plan prohibits supplementing wolf numbers after five years, thus limiting “long-term trammeling in the wilderness.”
And what if the plan fails and society demands another round of wolf “infusions” 20 years from now? “I can’t speak to what happens that far into the future,” Romanski said. “We’ve decided it’s a good idea for now, but whether it happens again depends on what the system looks like, and what happens to the island’s predator-prey relationships.”
Heberlein, meanwhile, stands by his May 2013 letter, which concluded: “Many people see wolves and nature as weak and needy. I doubt an editorial titled ‘Let wolves die for science’ will ever appear in the New York Times. So here’s my prediction: Efforts to restore naturally declining wolf populations on Isle Royale will one day be judged in the same category as the National Park Service’s eradication of ‘bad’ wolves in Yellowstone in the 1920s.”
Feature image via Michael Mauro.