TRAVERSE CITY, Mich. (AP) — No additional gray wolves will be transplanted to Isle Royale National Park for now, the park’s top manager said Wednesday, despite concerns that the Lake Superior island chain’s dwindling and inbred population might not survive much longer.
After consulting with experts and reviewing comments from the public, Isle Royale Superintendent Phyllis Green said staffers will develop a management plan that considers the wolves’ long-term survival prospects and their interactions with moose. The two species’ predator-prey relationship is the subject of one of the world’s longest scientific studies of its type, now in its 56th year.
It will take about three years to craft the plan, which also will focus on park vegetation and the effects of climate change, Green said. Officials could reconsider augmenting the wolf population if gender imbalance prevents them from reproducing or if moose begin overbrowsing trees and bushes, stripping them of leaves and needles.
“As long as there’s a breeding population, we’re going to let these animals have a chance to live their lives without us intervening,” Green said.
Scientists, park officials and wildlife advocates are divided over whether to attempt a rescue of the wolves, a popular attraction for visitors even though most never glimpse the wily creatures.
They are a relatively recent addition to the landscape. The first arrivals are believed to have crossed an ice bridge extending some 18 miles from the mainland near the Canada-Minnesota border in the late 1940s.
Moose had made their way to Isle Royale a half-century earlier, probably by swimming, and had suffered a recent population crash from overbrowsing when there was little left to eat. As wolf numbers grew, they helped keep the moose in check.
The wolf population has averaged 23 but fallen drastically in recent years because of inbreeding, disease and a temporary moose shortage. Only eight wolves were counted a year ago, the least since the 1950s. Two pups are believed to have been born since then, while one wolf escaped over the ice this winter and was shot dead on the mainland, leaving the current total at nine.
Rolf Peterson and John Vucetich of Michigan Technological University, the scientists who lead the wolf-moose study, are campaigning to bring more wolves to the 45-mile-long archipelago. Vucetich declined comment about Green’s decision Wednesday but said he and Peterson would issue a statement next week.
Because Isle Royale is a federal wilderness area where human influence is strictly limited, some contend nature should take its course, even if the wolves or moose disappear. Peterson and Vucetich say the principle of nonintervention is outdated when people have altered virtually every corner of the planet. More important now is keeping ecosystems healthy, with or without human involvement, they say.
“As long as there are moose on Isle Royale there should be wolves on Isle Royale,” Vucetich said in a 2013 interview.
Green said tinkering with the island’s ecology could have unforeseen consequences. While some scientists believe the wolves could die out in a few years, others say they could survive up to 25 years, which suggests there is time for careful consideration including a study with the U.S. Geological Survey of moose effects on vegetation, she said.
The wolves are a “compelling story,” Green said, but park managers must consider “a larger stewardship picture that considers all factors, including prey species, habitat and climate change, which could in a few generations alter the food base that supports wildlife as we know it on Isle Royale.”