Environmental Review Toolkit
Water, Wetlands, and Wildlife

pic of small map showing linkages
The Durango-Pagosa Springs Linkage along Highway 160. The linkage area is displayed with public landownership, locations inventoried during the roadway assessment, and identified focal zones. (CDOT)
pic of wildlife fencing and gate
Wildlife fencing and one-way gate. (CDOT)
pic of box culvert
Box culvert with low openness ratio at Raton Pass. (CDOT)

Colorado Department of Transportation

Linking Colorado's Landscapes

It's about connections. Wildlife on the move need natural linkages between blocks of habitat--environmental connectors offering them the food, shelter, and security they need as they travel through vastly different landscapes.

To identify and prioritize these vital linkages in Colorado, the Colorado Department of Transportation (CDOT) used funds from an FHWA streamlining grant to launch a collaborative scientific effort called Linking Colorado's Landscapes. The CDOT asked the Southern Rockies Ecosystem Project (SREP), a non-profit conservation organization in Denver, to spearhead the effort and recommend mitigation measures. The SREP was uniquely positioned to lead the project because of its comprehensive database of wildlife and migration patterns in the Southern Rockies, and the organization could expand on CDOT's earlier work in identifying 13 key wildlife-crossing areas in the I-70 transportation corridor.

First, SREP held a series of interagency workshops in which participating environmental experts analyzed the effects of habitat fragmentation and restricted wildlife movement in Colorado. They identified and evaluated 176 wildlife linkages across the state, assigning "high priority" status to 23 linkages recognized as more important for both wildlife and safety. Of these prioritized linkages, 12 were earmarked for further study. These were located on stretches of seven highways: SH 13, I-25, U.S. 50, U.S. 285; U.S. 550, U.S. 160, and U.S. 24.

In their decision-making, the workshop participants used a "landscape approach" which considered land use and other regional factors. They were aided by technology--habitat connectivity models developed by Colorado State University for deer, elk, bobcat, black bear, Canada lynx, and mountain lion.

Next, SREP staff visited and inventoried the 12 linkages at the points where they were bisected by highways. At the same time, Colorado State researchers developed geographic information system computer models of the landscapes important for wildlife movement.

The collected information was then combined with animal-vehicle collision statistics, traffic densities, land ownership, zoning, and other transportation-planning information, to enable the final recommendations phase. Together, SREP, CDOT, the Colorado Division of Wildlife, The Nature Conservancy, and the U.S. Forest Service, came up with site-specific recommendations CDOT could use immediately and in the future--recommendations like escape ramps for elk that accidentally get trapped on the roadside (one-way gates on deer fencing are too narrow for elk).

Thanks to Linking Colorado's Landscapes, large mammals and wide-ranging carnivores in Colorado are getting a lucky break. Transportation planners, engineers, community leaders, and conservationists committed to linking wildlife habitats are lucky too. Now they can access, and consider, recommendations for safer-passage mitigation measures at the mileposts with the greatest potential benefit to wildlife movement and the best opportunities for implementing those measures.

For more information, contact Rolland Wostl, Roland.Wostl@dot.state.co.us

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