Researchers looked at how wildlife crossing structures help maintain the health of grizzly and black bear populations.
"Showing that the black bears and grizzlies using the crossings to traverse the highway are also breeding is a major finding," said former Montana State University graduate student and WTI scientist Michael Sawaya, who wrote the paper for his doctorate, said in a news release. "While there have been a lot of studies showing that wildlife are using these crossings, this is the first time anyone has shown that animals using the crossings are breeding often enough to ensure that the populations on either side of the highway are not being genetically isolated."
The 44 crossings along the Trans-Canada Highway make up the "most extensive system of wildlife crossing structures on the planet," the news release reported. They are meant to prevent fragmentation of bear communities as a result of man-made structures like roads.
"These wildlife crossing structures cost millions of dollars and this is one of the first studies that has shown that they are doing what they are intended to do,"MSU professor of ecology Steven Kalinowski said in the news release. "If the bears aren't crossing the road and breeding, you're going to have fragmented and inbred populations on each side of the road."
Researchers looked at DNA from bear hair samples collected from wire snares along the Trans-Canada to see what animals had passed through and if they had produced offspring.
Some of the bears proved to be comfortable looking for mates on both sides of the road, one black bear even sired 11 cubs with five females.
Grizzly bears are believed to be more easily effected by human infrastructure; about 47 percent of black bears that used the crossing successfully bred compared to only 27 percent of grizzly bears. The team found once the grizzly becomes accustom to the crossing they will use it, allowing them to spread their parentage.
"It's really nice to end it on high note," Sawaya said.
