Wildlife Crossings Protect People, Animals, and Ecosystems
Wildlife crossings have been in the news - you may remember the viral video of the momma bear trying to get her cubs across the road from a couple years ago! So, what are designated wildlife crossings, and how do they protect people, animals, and even ecosystems?
Animals move throughout their habitats and across their ranges for a few main reasons: mating, foraging, and shelter. As humans have been developing more and more infrastructure, we are often destroying animals’ habitats or, increasingly, overlapping with them (resulting in a unique ecotone known as the wildlife-urban interface). As a result, interactions with wildlife are increasing; over the most recently studied 15-year period, wildlife-vehicle collisions have increased by 50%.
Photo Credit: Road Travel America, Flickr
One popular solution? Wildlife crossings. These most often take the form of bridges and overpasses (covered with native vegetation) or underpasses and tunnels. Learn more about the benefits of wildlife crossings for people, animals, and ecosystems with the infographic below.
If you are using a screen reader, please click here for a detailed description of the infographic.
Infographic made by Hailey Robe using Canva
While the benefits of wildlife crossings seem clear, what about the costs of installing them? And, do animals actually use them?
Costs of Installation
Costs of building wildlife crossings can be in the hundreds of thousands to millions, depending on the area in question, the type of crossing, and the number of crossings being built. For example, a recent project in Colorado allocated $12 million of a transportation budget to create two overpasses and five underpasses - and this has resulted in a 90% drop in wildlife-vehicle collisions! As discussed in the infographic, the economic benefits (and cost of human and animal lives and injuries) far outweigh the costs of installing wildlife crossings.
Plus, federal organizations are increasingly offering grants to assist states in building this infrastructure; this is expected to continue under the Infrastructure Investment and Jobs Act of 2021.
Do Animals Actually Use Wildlife Crossings?
Photo Credit: Yellowstone National Park, Flickr
Yes! Ultimately, wildlife are 146% more likely to use wildlife crossings than to cross at other locations.
The best case study for wildlife crossings may be the Trans-Canada Highway in Banff National Park. Studies of these crossings demonstrated that wildlife crossings specifically helped grizzly bears maintain genetic diversity and resulted in an 80% reduction in vehicle accidents involving wildlife.
It is worth noting that thorough wildlife monitoring and research must be done while planning wildlife crossing installations; this will help determine which species will best respond to which kinds of crossings. For example…
Mountain lions and black bears prefer “long, low, and narrow crossings” (Yellowstone to Yukon Conservation Initiative)
Grizzly bears, elk, moose, and deer prefer crossings that are “high, wide, and short in length” (Yellowstone to Yukon Conservation Initiative)
When animals decide to use newly-built wildlife crossings can also vary; elk have been observed utilizing crossings while they are still under construction, while it has been documented that grizzly bears may take up to five years to trust and utilize new crossings.
In Colorado…
A 2016 project by Colorado Department of Transportation (CDOT) built our first wildlife crossing system on Highway 9 - learn more about this hugely successful project here. And, in December 2023, CDOT received a grant to build a wildlife overpass on I-25! It will be one of the largest overpass structures in North America, connecting ungulate habitats on either side of the highway.
“As a community, we are leading the way when it comes to wildlife crossings, reducing traffic jams and improving safety in the process. Thanks to the support of Colorado’s federal delegation, local communities, and the Colorado Department of Transportation’s dedicated environmental teams, we are excited to move forward with the Greenland Wildlife Overpass.”
Quote from Governor Jared Polis (Twitter/X)
I am excited for this project and all the support it has generated, and I hope to see more Colorado wildlife crossings in the future!
