BOZEMAN — An international group of engineers, ecologists and landscape architects joined forces recently at Montana State University for an unusual challenge: designing wildlife crossing structures built from a material that has never been used for that purpose in North America.
During a workshop hosted by MSU’s Western Transportation Institute on May 10-11, the designers studied topographic maps, exchanged ideas and sketched bridge-like structures that could be fashioned from a high-strength plastic in order to provide elk, grizzly bears and other animals a safe route over roadways.
“Often, engineers design something and then maybe tack on what the plants and animals need, but here, we’re all together before we even start thinking about the structure,” said WTI researcher Rob Ament.
The meeting focused on harnessing the potential of fiber-reinforced plastic, a material commonly used in the aerospace and automotive industries and now being applied in large-scale construction in other parts of the world. Because the material is relatively lightweight and inexpensive, Ament said it could make it possible to create and install more crossing structures, which are typically made of concrete or metal. Because the material is also very durable, it could even make it possible to relocate and reuse those crossings if animals change their migration patterns, for example.
“Because we’re dealing with a new material, it’s fun to see the engineers stimulate ideas for the ecologists,” Ament said.
Roughly half the 15 participants were visiting from Toronto, where Ryerson University’s Ecological Design Lab has a tradition of collaborating with WTI.
“Because WTI is kind of the epicenter of (research on) road ecology, it made sense for us to come here,” said Nina-Marie Lister, director of the Ecological Design Lab and associate professor in Ryerson’s School of Urban and Regional Planning. She and Ament are co-investigators on a three-year grant funded by the Social Sciences and Humanities Research Council of Canada to study integrated approaches to designing landscape connectivity and wildlife mobility.
WTI researchers have played a leading role in guiding the development of wildlife crossing structures internationally. Tony Clevenger, a senior research scientist at WTI who attended the workshop, has been a primary consultant on the world’s largest complex of wildlife crossing structures, which consists of tree-covered overpasses and earth-lined culverts along a roughly 51-mile stretch of the Trans-Canada Highway through Banff National Park.
According to Clevenger’s research, nearly a dozen species of large mammals have used the Banff structures more than 150,000 times, and the mortality rates for large carnivores such as grizzly bears are now 50 to 100 percent lower where the crossings have been installed.
On May 11, as the two design teams prepared to present their prototypes for wildlife crossings in Hyalite Canyon and at Bozeman Pass on Interstate 90, Lister said she was looking forward to seeing the creativity generated by interdisciplinary conversation.
“We think we can achieve greater economy of scale and innovation if we work together,” Lister said.
WTI’s executive director, Steve Albert, commented that the structures could possibly also be used to provide safe and easy crossing for pedestrians in a municipal setting.
Matt Bell, who is working toward a master’s in civil engineering in MSU’s Norm Asbjornson College of Engineering, studied the other team’s design on the whiteboard and commented that “reduced labor cost is one thing they’re looking at, so I like that.”
The designs included unique details such as pre-cast indentations — like those in an egg carton — that could help the overlaid soil retain moisture, supporting the growth of grassy cover. All of the hypothetical structures shared in the basic goal of making it as easy as possible to give wild creatures options for moving across the landscape without risking deadly collision with vehicles.
“If we simply look at the safety benefits (to motorists), it makes sense,” said Jerry Stephens, who was taking a break from his normal duties as head of MSU’s Department of Civil Engineering to lend his expertise to the design challenge.
“These are something we should be looking at much more,” Stephens said.