Worldwide, roads act as both death traps and barriers for wildlife, fragmenting the landscapes animals need to survive. However, ecologists and engineers are working to “reconnect the wild” through the strategic construction of wildlife crossings.
As Mongabay contributor Ben Goldfarb reports, structures, including underpasses and massive overpasses paired with roadside fencing, have proved highly effective at protecting both animals and people.
The U.S. state of Colorado, for example, recently completed a 61-meter-wide (200-foot) overpass — one of the largest in the world — near the town of Greenland. It’s expected to help reduce roadkill by 90% along a critical stretch of I-25, one of the busiest highways in the western U.S. Similarly, the upcoming Wallis Annenberg Wildlife Crossing in California will soon allow pumas to safely traverse the 10-lane U.S. 101 freeway.
“At this point, there’s really no more question that these things can help populations,” Mike Sawaya, a researcher studying grizzly bears and wildlife crossings in Canada’s Banff National Park, told Mongabay.
The motivation for these projects is not only conservation but also public safety and economics. Collisions with white-tailed deer kill about 440 motorists each year across the U.S. Large animal collisions cost the U.S. economy more than $10 billion annually.
Other countries have also implemented these crossings. A mountain highway in Croatia is one of the most permeable roads on Earth, while India is pioneering “red roads” to reduce vehicle speeds in wildlife zones without abrupt braking, vehicle damage, or driver discomfort. In Sri Lanka, inexpensive rope bridges made of steel cables connected by nylon netting have allowed purple-faced langurs to safely cross between fragmented habitats without descending to the forest floor.
“Canopy crossings” like these have reconnected treetops for samango monkeys in South Africa and sloths in Costa Rica. Unlike many conventional wildlife crossings, rope bridges and ladders are portable and inexpensive: some designs cost only a few hundred dollars to construct and install.
Despite this progress, ecologist William Laurance warns that crossings alone can’t stop the “infrastructure tsunami” of new development that can increase poaching, industrial logging, farming, mining, and introduce and disperse invasive species.
Renee Callahan, executive director of ARC Solutions, a group that studies and advocates for wildlife crossings, told Mongabay that “we could solve this problem in a generation,” given sufficient investment.
The United States is debating just such investment for the Wildlife Crossings Pilot Program, established in 2021 with $350 million in funding. Many worthy projects were turned down due to a lack of funds, so legislators are working to expand and formalize support. A bipartisan transportation bill in the U.S. House of Representatives proposes $80 million annually for crossings over the next five years, while a U.S. Senate bill seeks $1 billion over the same period.
Read the full story by Ben Goldfarb here.
Banner image of one of the dozens of wildlife overpasses that allow safe passage for animals in Canada’s Banff National Park. Image by Ben Goldfarb.
This story first appeared on Mongabay
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