Wolverines are big weasels with an even bigger attitude. Legendary for their ferocity, they are rumoured to willingly fight wolves and grizzly bears to defend or scavenge prey. Yet despite their fierce reputation, new research from Dr. Jason Fisher and Nicole Heim, scientists at Canada's Alberta Innovates & Tech Futures, suggests wolverines are wary when it comes to human development.
“Wolverine distribution along the Rockies is unexpectedly close to the border of protected areas,” says Fisher. His research found wolverines are more abundant in the rugged terrain of national and provincial parks, despite what should be good habitat in transitional landscapes between the Rocky Mountains and Alberta prairie.
What could possibly deter the tenacious wolverine, known to routinely scour steep mountain passes in the depths of winter, and travel hundreds of kilometres through gnarly terrain to scavenge a caribou kill?
Fisher says it is a combination of factors, but has something to do with linear features like roads and seismic lines introduced by industries like forestry, and oil and gas. Biologists call these features linear disturbances.
“We know from past research that linear disturbances have the potential to disrupt predator-prey relationships and affect competition between predators,” says Fisher. He points to the known advantages linear features have given wolves when hunting caribou. Wolves have been shown to locate prey more readily, and travel with more speed.
However, what is an advantage for one predator might disadvantage another. Fisher theorizes that in unaltered systems, wolverines have a competitive edge because of their ability to travel in extreme terrain to find prey. However, the availability of easier travel on linear pathways may cause them to lose out to other predators.
Preliminary results from Fisher and Heim’s research in southern Alberta support this. “What we’re seeing is a lot of activity by foxes and coyotes, and fewer wolverines, in areas with high densities of linear features,” says Fisher, who wonders if these canids are out-competing wolverines.
When you combine this with things like the wolverine’s natural preference for rugged land cover, and changes to snowpack from a warming climate, Fisher says, “It’s a perfect storm of circumstances that may discourage wolverines from the landscape. ”
Historically, wolverines ranged over much of Canada. As is the case with many of the great carnivores on this continent, their range has contracted since the arrival of European settlers.
Fisher says it’s not clear how much a range can be compromised before wolverines disappear. “It’s not really a case of whether or not wolverines will go extinct. We’re a long ways off of that,” says Fisher, who adds that surrounding populations in British Columbia and the Yukon are relatively healthy. “It’s more a case of whether or not they’ll be extirpated from their current mountain range outside of Alberta’s protected areas.”
Determining the likelihood of wolverine extirpation has, in the past, been impeded by lack of data. The Province of Alberta sites this deficiency as a barrier in determining an accurate conservation status. This is reflected in the current provincial designation of wolverines as “May Be at Risk.”
Fisher’s been working for ten years to change this, having spent the majority of his PhD developing techniques to study rare and elusive species. Using DNA collected from hair traps combined with infrared-triggered cameras, Fisher and colleagues collected some of the first reliable population data for wolverines in Alberta.
Now Fisher and Heim have used these techniques to link low densities of wolverines to industrial activities. Can steps be taken to return these animals to human-altered landscapes?
“There is always a solution,” says Fisher. “It’s just knowing what exactly the problem is, so that we can find it.”
