VOYAGEURS NATIONAL PARK, Minnesota — Researchers studying wolves in northern Minnesota have released a new report showing how the killing of beavers by wolves can dramatically impact the ecosystem.
The report from the Voyageurs Wolf Project was published last week in the journal Science Advances.
A video summarizing the study findings is posted on the project's Facebook page.
Beavers are considered "ecosystem engineers" because the dams they build create so much of the wetland in the boreal forest, creating new habitat for a variety of animals and plants.
Wolves often prey on beavers, with one study in Alberta finding that they comprise up to one-third of their summertime diet.
The Voyageurs Wolf Project team tracked about 30 wolves that had been fitted with GPS collars.
It looked at how their predation on individual beavers that had dispersed from colonies affected the status of newly-created or recolonized ponds.
When a wolf's travel pattern indicated it had made a kill, the team visited the kill site to find evidence confirming the death of a beaver.
Through aerial surveys and on-site inspections, the researchers found that while 84 per cent of newly-created or recolonized beaver ponds remained active until the fall, no ponds remained active after a wolf killed the beavers that had colonized them.
Dispersing beavers are primarily solitary, so if they are killed their dams will ultimately fail for lack of ongoing maintenance.
This is significant because it preempts the significant environmental change that occurs in the forest when it completes the transition to a wetland.
"By affecting where and when beavers engineer ecosystems, wolves alter all of the ecological processes such as water storage, nutrient cycling, and forest succession," a summary of the study report says.
The research team believes the data it collected also suggests the ecological effects caused by the intervention of wolves may last for several years
"Predators can have outsized ecological effects by killing prey that have a disproportionately large role in ecosystem functioning," the report concludes.
It says the study should be helpful for understanding how the conservation and restoration of predator populations might affect ecosystems.
However, even though individual wolf packs in the study area are capable of consuming about 40 per cent of the beaver population within their territory, the authors found no evidence to suggest the beaver population in the Voyageurs National Park area is in danger.
The park has sustained a dense and stable beaver population for over 30 years, as well as a high-density wolf population.
Last month, the Voyageurs Wolf Project reported the death, west of Thunder Bay, of a collared wolf that travelled from Minnesota to Lake Nipigon last summer.
The project is a collaboration between the University of Minnesota and Voyageurs National Park, with funding assistance from the Minnesota Environment and Natural Resources Trust Fund.