A pause in B.C. heli-skiing operations during the first year of the COVID-19 pandemic led some endangered caribou populations to more than double their home-ranges, a new study has found.
The research, published in the journal Animal Conservation last week, came amid what the authors described as “Earth’s sixth major episode of mass extinction” and suggests human presence alone could be limiting mountain caribou’s access to food.
“It’s been shocking,” said Ryan Gill, the study’s lead author and a biologist at the University of British Columbia’s Okanagan (UBCO) campus.
“Without any physical changes to the landscape, just our presence can affect how wildlife use space in the natural environment.”
Southern mountain caribou once ranged as far south as Idaho, but today they hold the tragic title as the latest large mammal to be wiped off the face of the contiguous United States.
In Canada, caribou can no longer be found in iconic national parks like Banff and Jasper. The species is listed as threatened but population declines and shrinking habitat have led federal authorities to recommend their status be downgraded to “endangered” for nearly a decade.
Death often comes to caribou in the jaws of a predator. But that deadly moment has deeper roots. Logging and oil and gas exploration have carved up forests across B.C., opening up paths for predators to hunt mountain caribou.
Without human influence, the species has adapted to escape that fate, migrating with the seasons from low- to high-elevation old-growth forests. Using their wide hooves, caribou can travel on top of deep snow and reach lichen hanging off trees in places few predators can reach.
Today, however, that same winter range overlaps with heli-skiing operations, a primary human disturbance in late winter stretching across 40,000 square kilometres of mountain, according to the study's authors.
Eddie Petryshen, conservation specialist with the Kootenay-based group Wildsight, said he hopes the latest study “rings some alarms” with the B.C. government and within the heli-ski industry.
“It’s really concerning in terms of cumulative effects. We’re already seeing those caribou hit by logging,” Petryshen said.
“[Heli-skiing] is an additional impact that is really, really significant.”
COVID-19 created a 'golden opportunity'
This is not the first time experts have raised concerns that the backcountry presence of people could be hurting caribou. In 2008, UBC masters student Nicola Freeman found evidence that caribou pellets had higher levels of stress hormone after being exposed to heli-skiing and snowmobiling. But that research was never published, and with no chance to measure what would happen in a counterfactual world where humans disappeared off the landscape, little work has been carried out since.
So when Canada closed its borders in response to the COVID-19 pandemic, leading to an 84 per cent decline in skier days across B.C., Gill said the “near absence” of human activity created a “golden opportunity” to measure the impact on caribou.
“Humans leave the landscape for one year — is anything really going to happen?” said Gill, who works between UBCO’s Quantitative Ecology Lab and Biodiversity Pathways, a independent research group focused on caribou.
“We weren't sure.”
To find out, Gill and five other biologists from UBCO and Environment and Climate Change Canada used collars fitted with GPS trackers to trace the movement of 120 female caribou between 2018 and 2022.
They were then released back into their three sub-populations — the Hart Ranges east of Prince George, Columbia North north of Revelstoke, and the Central Selkirk region north of Nakusp.
Every 13 hours, the GPS devices would beam a signal back to the scientists. The researchers then compared the animals’ movement with a series of digital maps showing terrain, forest type, seasonal snowfall and approved commercial heli-ski tenures.
Whether the heli-skiers were present or not, the biologists found caribou continued to seek out high elevations, gentle terrain and the old forests rich in the arboreal lichen the species survives on.
What changed was how far they could travel to track down food. During the 2020 “anthropause,” the mean home-range of the three caribou groups grew 80 to 120 per cent larger compared to years when normal ski operations dominated.
Caribou movement also shot up, climbing to 11.9 square kilometres from 7.8 square kilometres in 2019 and 8.7 square kilometres in 2021, the study found.
The results, concluded the researchers, show that heli-skiing operations may be restricting the late winter movements of southern mountain caribou. As the animals avoid encounters with people, the area they gather food from may becoming increasingly limited.
“Wildlife can't perceive our intentions,” Gill said. “When we're out there, and we see an animal we think, ‘Oh, that was a nice animal’ and ‘We’re just here to look at it.’ Ungulates especially, perceive us as predators. They perceive any interaction with a human as a potential predatory event.”
Heli-ski group says it hasn't given up on expired agreement
The research comes six years after the expiration of a memorandum of understanding (MoU) between the heli-ski industry and the B.C. government. The agreement said that operators must remain 500 metres away from caribou while in flight, and if the animals were seen, skiers should avoid the area for 48 hours.
Even if that agreement was renewed, the authors of the latest report said the measures “may not be sufficient to mitigate the negative effects of heli-skiing on caribou” and that protocols “should be revisited.”
Ross Cloutier, executive director Helicat Canada, said that while he would “carefully” review the latest study, the pilots and guides that make up the industry group’s members “still adhered to” the MoU's provisions “just as though the agreement existed.”
Cloutier said “reasonable increases” to the 500-metre flight distance and 48-hour restriction “could be accommodated.” On the other hand, ”unreasonable increases would definitely result in business impacts and closures.”
“We are in continual discussions with the government related to wildlife management and we are very supportive of caribou recovery efforts. I have no information as to when, or if, wildlife policies will be renegotiated,” he said.
A spokesperson for the Ministry of Water, Land and Resource Stewardship said it's working with heli-ski operators — as well as all other users of Crown land — to “mitigate any potential negative impacts” on wildlife, including caribou.
“We have been reviewing current management practices for some time, and we will be making appropriate changes to address improvements in technology and increased understanding of the challenges facing species at risk, such as the southern mountain caribou,” said the spokesperson.
The ministry added that it supplied background data to the authors of the study and would incorporate its results to address concerns around species at risk.
“There's still a lot of unknowns,” Gill said. “I mean, we don't know where the heli-ski industry fly and how they fly and where they are relative to those animals. That's a big piece of the equation that we don't understand.”
Mapping needed to show the way
Without maps to show the way, Gill said spotting wildlife from the helicopter is incredibly challenging even when you know they are there. Add managing the risk of flying and keeping people safe, and it becomes untenable, he said.
“The burden is on the pilots and the ski guides which is kind of an impossible task,” he said.
“It's unfair to those people.”
To that end, Gill is working to layer Strava data, an open-source GPS platform used by athletes, to track where the heli-skiing operators go. That way the province can start to see on maps the kind of buffer zone the caribou really need.
Even better, said Gill, would be unreleased flight log data, something the heli-ski industry is still negotiating with the B.C. government.
Inevitably, said the long-time Revelstoke resident, who counts many friends who work the heli-ski industry, any regulation is going to require sacrifices on all sides.
“If there's limitations to where they can operate… it’s going to have an affect on their bottom line,” Gill said.
“There might be some awkward conversations at Christmas parties. There might be invitations rescinded. But I think that the majority of people on the ground, they want to do the right thing.”