Isle Royale wolves and moose

Editorial from the early December 2013 North Woods Call

    There’s a classic struggle for survival on Isle Royale.
    As previously reported in The North Woods Call, the wolves and moose living on the remote Lake Superior wilderness island are dependent on each other and both are threatened by a variety of factors.
     The wolf population has been in decline and may eventually die-out—due largely to reproductive challenges, disease, and a lack of genetic diversity caused by decades of inbreeding. Moose, meanwhile, may be faced with a similar fate—not only on Isle Royale, but across North America.  There have been preferential food shortages and a warmer climate in recent years has produced more parasites—especially ticks, which consume the flesh of animals and make them more susceptible to anemia and infections.  Ticks also bite off the hair of moose, exposing them to hypothermia in cold weather.
     On Isle Royale, wolves and moose have a unique predator-prey relationship.  Wolves are the only predator of the moose and the moose are almost exclusively the only prey for wolves.  It is essential to keep their respective populations in balance for a healthy ecosystem.
    Consequently, a debate currently rages over whether humans should intervene in this natural cycle and, if so, what the results might be.
   As one of our readers recently pointed out, the conundrum is this:  If you artificially boost the wolf population and their main diet—moose—are dying out, the wolves will starve to death.  If, however, the wolves die out, moose will—for a short time, at least—grow in numbers.  Then they will overeat the fauna, devastate the island ecosystem and either die out by starvation, or succumb to the tick infestation.
    What’s the National Park Service to do?  Though we prefer to let nature govern itself, the agency will probably have to err on the side of intervention.
   Population biologist John Vucetich and wildlife ecologist Rolf Peterson, who have studied Isle Royale’s wolves and moose, say a healthy ecosystem depends on the presence of top predators like wolves when large herbivores such as moose are present.
   Without this balance, prey tend to become overabundant and decimate plants and trees that many species of birds, mammals and insects depend upon. Top predators also maintain the diversity of rare plants and insects that depend on those plants.
    In addition, the loss of top predators may disturb the nutrient cycling of entire ecosystems, according to Vucetich and Peterson.  And wolves are a boon to foxes, eagles, ravens and other species that scavenge from carcasses that wolves provide, they said.
    Although wilderness is typically viewed as a place where nature should be allowed to take its course free from human interference, we lean toward the experts who say the ecology of Isle Royale would best be served if the National Park Service initiates a genetic rescue by introducing new wolves to the island.
    After all, Vucetich and Peterson said in a New York Times op-ed piece, “there’s no place on the planet that is untouched by humans.  We have already altered nature’s course everywhere.  Our future relationship with nature will be more complicated.  Stepping in will sometimes be wise, but not always. ... Navigating that complexity without hubris will be a great challenge.”