ICYMI: MSU Study Shows Impacts of Land Bridges for Grizzlies

Aaron Flint posted on February 26, 2014 15:23 :: 3393 Views

In case you missed this story from last week, The University Herald did a piece on research out of Montana State University.

University Herald: Natural Land Bridges Help Grizzly And Black Bears Travel Between Montana And Canada, Increasing Genetic Diversity

On the border between Montana and Canada, 44 natural overpasses form the world’s largest network of crossings. Specifically targeted to black bears and grizzly bears, they’re helping ensure genetic diversity within the two species, according to a new study from the Western Transportation Institute (WTI) at Montana State University.

Other projects have studied the effectiveness of the crossings — which from an aerial perspective depict stunning and natural-looking land bridges (see picture below) — in terms of limiting roadside deaths and encouraging mobility, but none have analyzed their impact on genetic diversity. Because bears have easier access to more geographical locations, they’re more likely to breed with a greater range of their kind, according to the press release.

Photos of the land bridges can also be found.  They look similar to the land bridges that Montanans will see as they travel on Highway 93 between Polson and Missoula. 

Here’s an excerpt of the full news release from Montana State University:

MSU professor of ecology Steven Kalinowski, who was Sawaya’s doctoral adviser and co-authored the paper, agreed that the genetic evidence offers the best indication to date of the success of Banff’s system of wildlife crossing structures.
The crossings – there are currently 44 in all – form the most extensive system of wildlife crossing structures on the planet. In addition to reducing collisions, the crossings project was designed to prevent fragmentation of wildlife populations living along Canada’s busiest highway. Grizzly bears, Banff’s marquee predator, are often negatively impacted by roads, Kalinowski added, so any true measure of the project’s success has to account for the impact on that population, which the Alberta government currently lists as threatened.
“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,” Kalinowski said. “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.”

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