New research by University of Alberta biologists paints a clearer picture of how food webs are shifting in response to changing habitats in Canada’s boreal forests, and what it means for dwindling caribou populations.
“We know that habitat, prey and predators such as wolves are all pieces of the caribou conservation puzzle, and here we were able to examine all the links in the chain at the same time across a large area,” said the study’s lead author, Rob Serrouya, director of the Caribou Monitoring Unit of the Alberta Biodiversity Monitoring Institute (ABMI).
“Our findings provide strong support for protecting habitat as the ultimate goal to maintain sustainable caribou populations, and reinforces the risk that elevated prey and predators may pose to caribou while habitat protection and restoration is ongoing,” Serrouya noted, adding that it can take several decades to restore a severely degraded ecosystem.
The group started with a measure of habitat alteration by human disturbance on the land—in the form of logging, roads, seismic disturbances and more. They found that areas that were more altered had higher levels of productive foods for some wildlife. Although this is good news for moose, deer and other hoofed animals, these increases in additional prey generally spell bad news for caribou. More moose means more wolves, which then opportunistically prey on caribou that are adapted to low productivity and low predator environments.
“Changes in the productivity of the land has the potential to substantially alter food webs, with positive outcomes for some species and negative outcomes for others,” explained Serrouya.
“Caribou are one of the greatest conservation challenges in North America, perhaps even the world,” said Serrouya. “Critical caribou habitat overlaps with resources that are valuable to people—including billions of dollars of oil and forestry. Understanding how to maintain caribou on the landscape, in a world with so much pressure to develop resources, may help to give them a fighting chance.”
The study, “Trophic consequences of terrestrial eutrophication for a threatened ungulate,” was published in Proceedings of the Royal Society B.