Public Release: 

UBC study finds family-friendly overpasses are needed to help grizzly bears

Design of wildlife road crossings is crucial for protecting grizzlies

University of British Columbia Okanagan campus

IMAGE

IMAGE: A screen shot from Banff's Temple overpass shows a female grizzly escorting her cubs across the Trans-Canada Highway. view more 

Credit: UBC Okanagan

Researchers have determined how female grizzly bears keep their cubs safe while crossing the Trans-Canada Highway.

Adam Ford, Canada Research Chair in Wildlife Restoration Ecology at UBC's Okanagan campus, along with Montana State University's Tony Clevenger, studied the travel patterns of grizzlies in Banff National Park between 1997 and 2014. In most cases, a mother bear travelling with cubs opted to use a wildlife overpass instead of a tunnel to cross the highway.

"We used data from Canada's longest and most detailed study of road-wildlife interactions," explains Ford, an assistant professor of biology. "We found that grizzly bear females and cubs preferred to use overpasses to cross the highway."

During the 17-year study period, bears not travelling in these family groups used both underpasses and overpasses. "You can't just build a tunnel under a highway and expect to conserve bears," says Ford. "Our work shows that the design of structures used to get bears across the road matters for reconnecting grizzly bear populations."

The study looked at five different wildlife crossing structure designs distributed across 44 sites along a 100-km stretch of the Trans-Canada Highway. The structures are purpose-built bridges or tunnels to facilitate the safe movement of animals across roads. Tracking and motion-triggered cameras were used to monitor grizzly bear movement and Ford says all grizzly bears selected larger and more open structures like overpasses and open-span bridges, compared to tunnels and box culverts.

"Since adult females and cubs drive population growth, this research tells us that overpasses are needed to protect bears in roaded areas," says Ford.

The study also documents the most cost-effective means to design highway mitigation. A common concern in conservation is how to allocate funding to bring the most effective gains for biodiversity. The researchers estimated the cost-effectiveness of structure designs and were surprised by the result.

"When we look at the population as a whole, there were a lot of passages made by males in box culverts, which is the cheapest type of structure to build," explains Clevenger, stressing that a diversity of wildlife crossing structure designs along a highway is essential.

"It's important to reduce the chances of adult males encountering cubs since the males will kill young bears," Clevenger adds. "Creating both 'bachelor' and 'family'-friendly designs will further help bear populations grow."

This peer-reviewed study was published online this week in the Wildlife Society Bulletin.

###

Media Contact:

Patty Wellborn
Assistant Communications Coordinator | University Relations
The University of British Columbia | Okanagan campus
Phone: 250-807-8463 | Cell: 250-317-0293
patty.wellborn@ubc.ca

ABOUT UBC's OKANAGAN CAMPUS

  • UBC's Okanagan campus is an innovative hub for research and learning in the heart of British Columbia's stunning Okanagan Valley.
  • Ranked among the top 20 public universities in the world, UBC is a globally recognized research-intensive institution whose Okanagan campus was established in 2005.
  • The Okanagan campus emphasizes smaller class sizes, experiential learning, and research activity for students, combining a world-class UBC degree with a tight-knit and entrepreneurial community.
  • As part of North America's most international university, the campus is home to 9,000 students representing 98 countries.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.