Wolverine numbers in parts of British Columbia and Alberta are dropping fast.
A study published at the end of October in Scientific Reports found rapid population declines taking place both inside and outside Canada’s National Parks. The authors used remote cameras and DNA sampling of wolverine hair to come up with regional population estimates of the wiry, mid-sized carnivore. They found the total number of wolverines had declined 41 percent in the last decade. The 2011 data revealed a measly 54 wolverines across the study area. By 2020, that number was down to 32.
Warming temperatures are part of the explanation. These storied members of the weasel family need deep snows to insulate the dens in which they raise their young. They scavenge animals swept away in avalanches and use snow to stash their kills for later consumption. Climbing winter temperatures are melting favorable wolverine habitat fast. With more warming already baked into the system, it is hard to see this situation improving soon.
Another factor impacting wolverines is disturbance. The study shows that park visitation around Banff has increased nearly 30% in the last decade. More hikers, climbers, and skiers make life much harder for a creature that prefers to be left alone. Increasing nighttime light from development also affects their survival. Wolverines cannot take much stress before their hunting and reproductive success plummets. Although recreation generally tracks the belief that parks are inspiring, biodiverse places, the resulting increase in people it brings comes with a cost.
Climate change and growing recreational impacts are not easy problems to solve. But there is one high-impact activity that is. Trapping. One hundred and six traplines crossed the study area. Researchers found 13% of the wolverine population are killed in traps each year compared to a maximum recommended harvest rate of 4%. This number is likely an underestimate given that compliance with reporting requirements is low and harvest data were missing for some years.
Legal harvest of wolverines in the BC portion of the study area ended in 2020 due to the overwhelming evidence of its harmful effects on the population. But it is still legal in other areas in BC and outside of parks in Alberta. Similar to the hunting and trapping of wolves in Montana, killing wildlife outside of the parks has spillover effects on park populations. More than 20% of Yellowstone National Park’s wolves were killed in the 2021-22 hunting season after they left the park. The parks are not adequate refuges for wide-ranging animals like wolves and wolverines that are subject to hunting.
To allow trapping in wolverine habitat is a non-sensical risk. The public interest doesn’t pencil out. The three parks in the study area (Banff, Yoho, and Kootenay) saw 5.35 million visitors in 2019 with visitation trends on the upswing. People come to the parks to see wildlife. Trapping, on the other hand, is in decline. British Columbia has approximately 1,200 trappers and the number of traplines reporting harvests has declined by 2/3 in the last few decades. It is a strange public policy that would risk the end of a uniquely adapted evolutionary line for the benefit of a few thousand trappers.
Data on population trends are extremely hard to collect with species as reclusive as the wolverine. The authors of the recent study point out that “adequate monitoring systems….are still lacking….because of funding constraints and logistical challenges.” But when you do get a solid data point, you need to act. Wolverines in this part of Canada are circling the drain. Trapping causes unsustainable mortality. It has to stop.
Government-funded science should be used to protect the public interest. What are we waiting for?