Mammals of the Mountain Slopes [2019]
Editor’s Note - Mountains and alpine environments have long been a refuge for mammals, so what happens when there’s increased human access and development in this terrain? By following remote wilderness cameras, scientists have been able to track animals to see how they’ve been adapting to the change. In this article from Jason T. Fisher and Alina C. Fisher highlight grizzly and wolverines as well as considerations for future developments.
This article first appeared in the newly released 2019 State of the Mountains Report. We'll continue to publish articles exploring the science on our current state of Canada's alpine on our blog throughout the year. Find them all here.
Note: All images in this article of moose, bears, cougars, and caribou were captured in their natural environs by motion sensing wilderness cameras. Photos: Jason Fisher.
Mountains: An animal refuge
Mountains are one of the last bastions for large mammals in North America. They are, in a way, ecological citadels where native species have been allowed to persist. Large ungulates – deer, moose, elk, sheep, and goats – have not been replaced by livestock; large predators have a refuge from persecution. However, the Anthropocene has not spared mountain environments from climate change and landscape change – which has encroached upon those fortress walls with mammals feeling those effects.
The Canadian Rocky Mountains are a special case of this global phenomenon. The western Canada sedimentary basin sprawling eastwards from the Rockies’ is rich in oil and gas, and its extraction fuels modern economies. Forest harvesting – and fire suppression to protect those resources – has been a mainstay of mountain environments for over a century, resulting in changed disturbance regimes. As per capita wealth has increased, recreation has both increased in popularity and changed from low-impact activities to high-impact ones, such as RVs and ATVs. The leisure industries, and the hyper-development that so often accompany them, have arrived at the mountains at last.
Increased human footprint and tracking change
The landscape change spurred by human activity has radically outpaced our ability to track those effects on mammal communities, or to understand their root causes. Consequently, the mountain mammal community has been changing, with us unaware. But technology is catching up here, too. Remote camera trapping has rapidly evolved over the last decade from a fun pastime into a vital scientific tool. Digital cameras can capture thousands of images, and when networked in an array of scores of cameras, yield insights undreamed of a decade ago. For the first time, we can effectively measure where mammals are on a landscape – and more importantly, where they are not, but should be. We can now reliably estimate the populations of multiple species in the same landscapes, to understand predator-prey interactions. We can measure their daily activity patterns, and even changes in their behaviours. For the first time, we can scientifically investigate the effects of the multiple forms of landscape change on entire mountain mammal communities. And the news, as one might assume, is a mixed bag of good and bad.
What’s happening with the grizzlies and wolverines
Grizzly bears are an iconic species at risk on the east slopes of the Rockies. A hunting moratorium in Alberta has stopped those population losses, but meanwhile road access has increased, resulting in bear deaths related to interactions with people. Even on the less developed British Columbia side, land-use that creates bear food (orchards, for instance) lures grizzlies in, and increases their chances of being killed – creating an ecological trap.
“The landscape change spurred by human activity has radically outpaced our ability to track those effects on mammal communities, or to understand their root causes.”
But grizzlies may not have the worst of it. The real canary in the coalmine is the wolverine. Wolverines used to inhabit multiple ecosystems spanning the entirety of Canada and the northern United States. European settlement reduced wolverine distribution, limiting their ranges to the Arctic and those mountain citadels. Generational amnesia has led many to believe that wolverines are a mountain species – but only inasmuch as mountains (and for now, some parts of the boreal forest) are the only places south of the Arctic we’ve left them to persist. As landscape change advances into mountain valleys and up the slopes, those areas are no longer wolverine refuges; and we are certain of this loss thanks to remote camera traps.
Research on Alberta Rocky Mountain wolverines started fifteen years ago in the Willmore Wilderness and the adjacent working landscapes of the east slopes and foothills. Cameras, along with hair capture and DNA analysis, showed that wolverines were doing fairly well in the Willmore, but were shockingly sparse in working landscapes: only five wolverines were found on that entire land base, three of which were likely a single family. In the 2010s, a collaboration of scientists expanded this research into Banff and Yoho national parks and the adjacent Kananaskis Country and Ghost Wilderness, spanning over 12,000 km2. Unfortunately, the same pattern occurs there: wolverines were doing well in the national parks, but outside, they were alarmingly sparse. In all of Kananaskis – long an icon of wolverine habitat – only seven wolverines were found, nicknamed “the Magnificent Seven.” In comparison, scores of wolverines lived in same-sized areas in the national parks.
The good news, and what needs to be done
The news is consistent all along the east slopes of the Rockies: wolverine range has contracted under our noses, and likely continues to do so. Careful analysis shows that the cumulative effects of climate change and landscape change – including forest harvesting, petroleum extraction transportation, and recreation – is to blame. Why this is happening is still being researched.
Yet good news remains. The same analysis on the entire carnivore community showed that the magnitude of these effects is not yet felt across all species. Lynx, cougars, bobcats, and other species still seem to be persisting, at least for the time being. However, even they showed signals of negative responses to extensive landscape change on the east slopes. How species will respond to near-future change is uncertain, but what is clear is that landscape management and protection is needed to ensure mountains remains citadels of refuge for mountain mammals.
Jason Fisher is an Adjunct Assistant Professor in the Faculty of Environmental Studies at the University of Victoria and Senior Research Scientist with InnoTech Alberta. Alina Fisher is an ecologist, freelance science writer and science communications researcher based in Victoria.