A collection of hundreds of thousands of photographs can say a lot. For Jonah Keim and his colleagues, the images illuminate a path to protecting endangered caribou without killing wolves.
For three years, researchers collected photos from more than a hundred motion-triggered cameras along game trails and mineral seismic lines in the Parker Caribou Range in northern BC. Last week, they published their findings in the journal Frontiers in Ecology and the Environment.
“It was really a study of how animals use the landscape in time and space,” said Keim, who has studied ecology and caribou for more than two decades.
“The real goal of our study was to figure out ways to restore their habitat.”
Encounters between boreal woodland caribou and wolves are naturally limited by the landscapes caribou choose to live in. Caribou favour boreal peatland, muskeg, and black spruce forests that predators struggle to move through efficiently.
“The habitats the caribou select are the habitats that many other species in the ecosystem avoid,” said Keim.
When mineral and oil exploration came to the area, companies left behind a network of roads and seismic lines. Predators now use that network as a web of access corridors to penetrate landscapes they wouldn’t normally bother hunting in.
Traditionally, the response of governments and researchers has been to cull the wolves to protect the caribou – one of the most endangered species in the world.
The Tłı̨chǫ and Northwest Territories governments are partners on a joint wolf management program in the territory. A 2020 pilot program allowed wolves to be shot from the sky if fewer than 100 had been harvested from the ground by mid-March. A regulatory body condemned the practice in January of this year.
The study said wolf culling is “socially, ethically, and ecologically” questionable.
“One of the responses in a predator-prey system – maybe it’s wolves, maybe it’s bears – is we just cull the predators, the wolves, to rebalance the system to try to help caribou recover,” said Keim.
“The reason this has been largely done and argued by governments and other scientists is because we don’t have an alternative. We don’t have another option.”
By analyzing the huge collection of photos, the researchers found an alternative: reclaim human disturbances to level the playing field between predators and prey.
Scientists have long understood habitat loss is a problem but the larger challenge, said Keim, is knowing how to restore it.
“Maybe it’s really about how easy it is to move on these features,” he said.
The researchers filmed themselves walking across the “features” – like roads and seismic lines – to gauge how quickly they could move along them compared to the surrounding natural environment. They then “treated” the human developments by building mounds, felling trees, or otherwise littering natural debris to mimic the nearby landscape.
The researchers treated 40 percent of the features in about one quarter of the reserve and left the rest untreated.
Encounters between wolves and caribou dropped by 85 percent in the treated area and increased outside it, as predators were displaced by the reclaimed features.
The researchers estimate it would “require removing most of the population” to achieve the same result by killing wolves.
Study a ‘baby step’ for cull alternatives
The study found habitat restoration, at least in a small slice of northern BC, could be more effective protection for caribou than wolf culling. But Stan Boutin, an ecologist at the University of Alberta, is concerned that the authors overstated the significance of their findings.
“They basically only did one year post-treatment, and only a small proportion of the caribou range and an even smaller proportion of any wolf territory. So it’s all pretty tiny in terms of scales of time and space,” he said.
Boutin said the upside to wolf culling, however ethically fraught, is that we know it works. He said we can’t be as sure when it comes to newer, experimental approaches.
“The article no doubt raised some good issues that ethically and socially we don’t like doing wolf control but, from the same standpoint, it has proven to stop caribou declines, if not allow them to recover,” he said.
“To some extent, this study is just the first baby step in looking at whether an alternate approach like this could have the same results as what you see with wolf control.”
The NWT’s Department of Environment and Natural Resources did not respond to a request for comment in time for publication.
“We were studying variables that told us how easy it is to move,” said Keim.
“And that’s what our paper said: recovering these habitats is really about reducing encounters between predator and prey, and we can do that through habitat restoration.”
The study was funded by the BC Oil and Gas Research and Innovation Society.
Correction: June 14, 2021 – 9:37 MT. This article initially referred to the University of Alberta ecologist as Stan Boutlin. His name is in fact Stan Boutin. Our report has been updated.