Frequently Asked Questions
A brief guide to help explain a complex issue
What is Isle Royale?
Isle Royale is an island located on Lake Superior and a part of Michigan. The island and its 450 smaller islands that surround it, make up Isle Royale National Park, given that distinction on April 3, 1940. In 1976 the island was declared a Wilderness Area. The island is 893 square miles and is located 20 miles off the coast of Minnesota’s North Shore and the mainland of Canada.
What is the Isle Royale Wolf and Moose Study?
The study is the longest continuous running predator-prey study in the world. Started in 1958, the purposes of the project are to better understand the ecology of predation and what that knowledge can teach us about our relationship with nature. A large function of the study is to conduct an annual winter count of the number of wolves and moose on Isle Royale.
Why are wolves disappearing from Isle Royale?
Wolves first came onto the island in the winter of 1948 over an ice bridge from mainland Canada. From that time on, wolves have been present on the island, reaching peak numbers in 1980 with 50 wolves. As the climate has warmed, fewer ice bridges have formed from mainland USA and Canada to the island. With fewer ice bridges, mainland wolves have had fewer opportunities to visit the island and breed with Isle Royale wolves, revitalizing the packs genetic diversity and ensuring success of the species. In 2018 only two wolves, closely related and unable to produce viable offspring, were left on the island.
What is an ice bridge?
An ice bridge is a frozen natural structure formed over water including lakes, rivers, and seas. They facilitate migration of animals or people over a body of water that was previously uncrossable by terrestrial animals. In the case of Isle Royale, these bridges often form to mainland Canada or northern Minnesota. Since 1994, the presence of ice bridges to Isle Royale have dramatically decreased. Depending on temperature and wind conditions, bridges can last for several days, weeks, or months.
How is climate change affecting Isle Royale?
The most obvious effect of climate change on Isle Royale is the increasing infrequency in the formation of ice bridges. Warming air temperatures translates to warmer water temperatures on Lake Superior, making it more difficult for ice bridges to form. This has a trickle-down effect. Fewer ice bridges means fewer wolves, and fewer wolves means an out of balance ecosystem. Additionally, data shows that moose may be negatively affected by warming air temperatures on Isle Royale. A majority of projections show that moose will not survive on the island in the next 50 to 100 years.
What is the significance of the presence of wolves on Isle Royale?
Predators are necessary for any healthy ecosystem. On Isle Royale, wolves are the top predator. They play an important role of mitigating and dampening the moose population that would otherwise grow unchecked. An abundance of moose can wreak havoc on the island’s vegetation due to overgrazing. This not only can greatly change the plant life and beauty of the island but will also eventually lead to a food shortage for moose, resulting in large-scale starvation events. A healthy ecosystem relies on a balanced predator-prey dynamic.
What is the National Park Service’s response?
In 2018 the National Park Service made the calculated decision to reintroduce 20-30 wolves over a three-year period onto the island from Minnesota, Michigan, and Ontario. This number of wolves is believed to have an immediate impact on the island’s moose population. After the introduction of wolves, the NPS plans to take a hands-off approach and allow the populations to fluctuate naturally. At the end of 2020, 19 wolves were relocated to the island. The translocated wolves have been equipped with GPS collars, along with 25 moose, to help track their location and better understand their behavior.
Why were people opposed to reintroducing wolves onto the island?
The most prominent argument against the idea of relocating wolves to Isle Royale has to do with the island’s status as a wilderness area. Ninety-nine percent of Isle Royale is both a national park and a wilderness area. The Wilderness Act of 1964 defines wilderness as “an area where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.” Opposition to the reintroduction argue that human intervention in Isle Royale’s ecosystem goes against the policy of the Wilderness Act.
Has this been done before?
There have been a number of cases of restoring apex predators to an ecosystem. The most notable and relevant example is the reintroduction of 41 wolves into Yellowstone National Park in 1995. At the end of 2020 there are eight packs consisting of 94 wolves. The program has been seen as a great success and has led to greater biodiversity throughout Yellowstone.
Where do things stand now?
At the end of 2020, there are believed to be a total of 14-16 wolves on the island. This number is a reflection of the 19 wolves relocated to the island as well as the two wolves that were on the island previously. Several wolves have died since relocation due to territorial disputes. In 2019, one recently relocated female wolf left the island on an ice bridge for mainland Canada. However, at least two wolf pups were born in early 2020, a key element of the relocation program’s success.