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An Assessment of Habitat Connectivity and Fracture Zones for Carnivores Within and Between the I-90, US Route 2, and WA State Highway 20 Corridors – UTC

Project #: 4W2397
Start Date: 10/01/2008
End Date: 09/30/2012
Status: Completed

Washington’s Cascade Mountains are important to the health of carnivore populations in Washington and neighboring regions, enabling animals to move within the ecosystem and allowing for genetic exchange with outside populations—a vital component of carnivore conservation. The permeability of highways and forest road networks is a key determinant of the ability of carnivores to move and disperse. When there are too many roads and high levels of vehicle traffic, transportation systems create “fracture zones” that are detrimental to wildlife populations because they increase mortality and inhibit natural patterns of animal movement. This scenario becomes all the more dire in the context of global climate change, which will require major geographical shifts for certain wildlife populations. To address this situation, WTI is collaborating with the USDA Forest Service, North Cascades National Park Service Complex, Conservation Northwest, the I-90 Wildlife Bridges Coalition, and the Washington Department of Transportation to collect detection and genetic data for a suite of focal carnivores, with the overarching goal of evaluating habitat connectivity and identifying barriers to animal movement. This landscape genetics initiative will complement other efforts within the state, including WTI’s existing wildlife monitoring project on behalf of the I-90 Snoqualmie Pass East Project, and Conservation Northwest’s efforts to advocate for high-quality wildlife passage. Further, the results of this research will permit validation of models being created by Washington’s statewide connectivity modeling effort.


WTI worked with the US Forest Service, US National Park Service, WSDOT, and others to assess habitat connectivity and the impact of landscape fracture zones on carnivore populations within and between the I-90, US Route 2, and State Highway 20 transportation corridors.


  • Robert Long
    Robert Long