For almost 60 years, the predator-prey relationship between wolves and moose on Isle Royale, a small island in the northwest part of Lake Superior in Michigan, has been the focus of ongoing research. In recent years, however, the number of wolves on the island has dwindled due to inbreeding; there now remain only two individuals—one male and one female—on the 200-square-mile island. This has led to unrestrained growth of the island’s moose herds, which graze extensively in the national park’s surrounding forest. The situation has sparked debate about whether to attempt a genetic rescue of the wolf population or forgo any intervention and allow extinction.
On September 22, the US National Park Service (NPS) announced its decision to restore the wolf population, and with it, the predator-prey dynamics. By the end of October, six wolves from Michigan and Minnesota will be airlifted to Isle Royale by the NPS. Additional transfers from Michigan as well as Ontario, Canada, are planned over the next three years in order to reach the goal of 20–30 relocated wolves. By reestablishing the wolf population, scientists hope to bring the expansion of moose herds under control.
The integration of the new wolves poses some interesting challenges. For example, it is not known whether there will be territorial conflicts between the remaining wolf pair and the newly integrated wolves. Park planners intend to release the new wolves outside of the remaining pair’s territory, but beyond that they do not plan to intervene.
Moreover, unlike Canadian wolves, Michigan and Minnesota wolves have little to no experience preying on moose. Rolf Peterson of Michigan Technical University tells Science that the relocated wolves will need to acquire the necessary skills. “Wolves are wonderful observational learners, and hunger is a strong motivation to test any potential prey.”