Higher road density leads to lower grizzly bear density, scientists from the University of Alberta have confirmed. This is a critical problem for a species still rebounding from a long period of human persecution.

The research examined dataset of grizzly bear activity in British Columbia based on “non-invasive DNA” taken from hair collection. 

Clayton Lamb, who is currently completing his PhD at the University of Alberta, said: “The problem with grizzly bears and roads is a North American-wide issue. This is the first study that strongly links roads to decreased grizzly bear density.”

Not only do bears die near roads, bears also avoid these areas, making many habitats with roads through them less effective. By closing roads, we can reduce the negative impact in a lot of ways. We can’t turn roads back into forest tomorrow, so the best thing we can do right now is to close them. The effects are immediate.”

Bear populations 

Lamb and his colleagues studied a threatened population of grizzlies in the Monashee Mountains, just east of the Okanagan, the leading edge of bear recovery efforts in British Columbia.

Lamb described the population as low but recovering, with a few bears slowly recolonising the Okanagan where they used to roam but are currently locally extinct, or extirpated. His comments came after the December 2017 closure of the grizzly bear hunt in British Columbia.

Lamb said: “Grizzly bears are recovering in a lot of areas, but habitat loss and human-bear conflict remain huge problems that can compromise recovery.”

“It is more important than ever that the public recognise the continuing threats to bear populations. Current road densities in British Columbia represent a problem for bear conservation.

“We are losing wilderness in the province, and there are fewer grizzly bears where road densities are high. We’re taking it another step further and advising that closing roads will do a lot to improve bear populations.”

Land management

Lamb said the findings can be applied to other habitats throughout North America.

Along with a new scientific paper, Lamb and his fellow conservation scientists produced a land management guide focused on maintaining the spatial integrity of the landscape to bolster grizzly bear density.

Lamb, who was born in British Columbia, said wildlife conservation was in his veins. “I grew up in the outdoors. I developed an increasing appreciation for wild places and conserving them. I realised that science was an outlet to protect these places and the species that inhabit them.”

On the back of Lamb’s work, road closures are already being planned for the Monashee Mountain area.

This Author

Catherine Harte is contributing editor of The Ecologist. This story is based on a news release from the University of Alberta. The study was recently published in the Journal of Applied Ecology.