More roads in grizzly bear habitat means more deaths

Closing roads would have an immediate impact in countering the effects of habitat loss for grizzly bears.

It's simple math, says a University of Alberta conservation biologist. More roads equals fewer grizzly bears.

In a recent study examining a non-invasive DNA (hair collection) dataset of grizzly bear activity in British Columbia, Clayton Lamb and his colleagues determined what scientists have long suspected: higher road density leads to lower grizzly bear density-a critical problem for a species still rebounding from a long period of human persecution.

"The problem with grizzly bears and roads is a North America-wide issue. This is the first study that strongly links roads to decreased grizzly bear density," said Lamb, currently completing his PhD with U of A conservation biologists Stan Boutin and Scott Nielsen.

"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."

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. He described the population as low but recovering, with a few bears slowly recolonizing the Okanagan where they used to roam but are now locally extinct, or extirpated.

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

He added it was more important than ever that the public recognize 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," he said after the B.C. government closed the grizzly bear hunt in December 2017.

Lamb said the findings can be applied to other habitats throughout North America. Along with a new scientific paper, Lamb and his colleagues, conservation scientists with the B.C. government, produced a land management guide focused on maintaining the spatial integrity of the landscape to bolster grizzly bear density.

Thanks to their work, roads closures are already in the works for the Monashee Mountain area.

"The Effect of Habitat Quality and Access Management on the Density of a Recovering Grizzly Bear Population" appears in the Jan. 9 issue of the Journal of Applied Ecology.