Isle Royale research shows healthy impact of wolves on moose herd
Several years ago, scientists re-introduced wolves to Isle Royale National Park off the shores of western Upper Peninsula in Lake Superior.
The wolf population is doing well on the island, with pups being born on the island for the first time in five years in 2020.
The increase of wolves on the island will likely lead to a healthier moose population, according to Sarah Hoy. She’s a research assistant professor at Michigan Tech University.
Hoy says it’s been a long-held notion that wolves prey on the weak moose in herd or population.
“Wolves are attempting to kill these really large animals with their teeth. There’s a reasonable chance that wolves could get injured or killed if they get kicked by a moose that’s trying to defend itself. Given those circumstances, you would expect that wolves would tackle easier prey,” said Hoy.
But research to prove this and learn more about its impact hasn’t been widely tested on Isle Royale.
Hoy and other researchers studied the bones of moose in the park to see what, if any diseases, they had when they died and if they were killed by wolves.
Their research suggests wolves were more likely to kill older moose or young moose with osteoarthritis.
“Probably the most interesting result that we found was that osteoarthritis has become less common in the moose population following years where wolves were killing a lot more moose,” said Hoy. “We think that decline in osteoarthritis follow years when wolves are killing a lot of moose because wolves are preferentially removing this old and arthritic from the population.”
Hoy says similar research done with the wolf/elk populations in Yellowstone National Park supports that this would be true of wolf-prey relationships in most places.
She also says it goes beyond just the health of the moose population.
“For example, wolves can potentially help the recovery and growth of tree species by reducing the number of deer, elk, and moose which graze on those plants. The carcasses the wolves leave behind also provide food for other species like ravens and foxes,” said Hoy. “I think this study adds another way which wolves are beneficial to keeping ecosystems healthy by regulating a chronic disease like osteoarthritis.”
Hoy says the results of this study have important implications for trying to understand wolf conservation.
She hopes research like this will be considered when groups and agencies are making wolf management decisions, especially when it comes to hunting.
“I think when we’re thinking about that decision of whether we should intensively hunt wolves or not it’s important to consider not only the issues that are caused by wolves, maybe the occasional predation of livestock, but also to consider all of the benefits that we get, that we have by having wolves on the landscape and the role that they play in removing diseased individuals,” said Hoy.