Isle Royale is a large island in Lake Superior and part of the state of Michigan. It, along with hundreds of other smaller islands, make up Isle Royale National Park. The island boasts boreal forests that are similar to those of Ontario and Minnesota. The habitat is, not surprising, ideal for large mammals like moose, and, of course, their predators: wolves.
While wolves once dominated Isle Royale and Michigan, they are struggling to maintain their presence on Isle Royale today. At their low point, only two remained. While conservationists have been transporting wolves to the isle, the predators have been subject to mysterious deaths, and the shrinking wolf population may have much to do with an alpha interloper.
The modern story of the Isle Royale wolves is as much about DNA as it is about habitat. According to Michigan Environment Watch, “a male wolf migrated from the mainland across an ice bridge to Isle Royale” during the late 1990s. This wolf, a clear alpha male, dominated the female wolves who lived on the isle. Through their genetic study, researchers discerned that this male wolf’s genes began to take over the genetic ancestry of the isle’s wolf population.
Though the initial infusion of these outside genes effectively ‘breathed new life’ into the local wolf population, their dominance eventually led to what the researchers dub an “inbreeding depression.” The isle’s wolves contain 60% of that outside male’s genes—a situation that astonished scientists. The inbreeding may be precisely the reason today’s Royale Isle wolves are struggling to survive, and the situation remains precarious.
When the population dropped to just two, conservationists knew they had to move other wolves into the habitat quickly. The belief was that outside genes, again, might initially benefit the local population. With further outside wolf introductions, scientists hope to avoid a future inbreeding depression. Unfortunately, the new wolves have been mysteriously dying, and scientists are struggling to understand why.
After one of the newly introduced wolves succumbed to pneumonia as determined by necropsy, two other wolves were discovered dead, but their bodies were too decomposed for effective study. One theory is that the wolves became weakened during their short stint in captivity before being released onto the isle. The theory has gained traction and has caused conservationists to amend their release plans. Instead of holding the wolves for up to 48 hours, they will release them in under 24 hours in order to minimize the trauma of captivity.
Some people may question why it’s important to maintain a wolf population in the national park. For one, it is the site of a famed predator-prey system study, a long-term study that involves the isle’s moose and wolf populations. Without the wolves, the moose population grows unchecked as this part of the world is quite remote.
Today, the Isle Royale wolf population is up to 17. A new wolf was added to the population back in September of this year. Park officials hope to get that number up to 20, at the least. Once the new wolves reach the isle, there is precious little opportunity to leave for the mainland short of the ice bridges that may pop up during the coldest periods of winter. The new wolves are chosen carefully in the hopes that their genes will enhance the local population.
For the time being, humans will need to stay involved in the plight of the Isle Royale wolves . The park remains closed to visitors from November 1st to April 15th annually, but you can plan a spring or summer park adventure there. The wolves are shy, but visitors have been able to catch glimpses of them and hear them too. Many, with the exception of the moose, are hoping the wolves finally make their comeback, maintaining a healthy presence on Isle Royale.