Enhancing Wildlife Communication Networks in the Pacific Northwest Through Strategic Road Construction
Animals throughout the Pacific Northwest rely on the ability to roam vast regions for their survival. Each year, a multitude of terrestrial creatures journey across the landscape to fulfill their survival needs. Some of these animals undertake annual seasonal migrations, such as the Crescent Herd of mule deer in central Oregon, traveling over 90 miles from their summer to winter ranges. Others, like a young cougar in Washington, travel extensively in search of food or territory, covering up to 1,165 miles over a four-month period.
Human activities, notably the creation of roadways and fences, fragment habitats into smaller, isolated patches, hindering wildlife movement. These infrastructures degrade critical resting sites along migration routes, disturb essential habitats for sensitive species, and contribute to noise pollution – all factors that may limit an animal's ability to access and utilize surrounding areas. Roads also provide easy access to previously inaccessible tracts of land, often leading to development, deforestation, and agricultural expansion. Across Washington, over 87,000 miles of roads have wiped out more than 174,000 acres of habitat,painting a grim picture, but hope remains.
Advocacy and targeted action can help restore landscape connectivity for various species to flourish. In Oregon and Washington, there is a growing awareness of the importance of reconnecting fragmented habitats. Defenders of Wildlife's Northwest Program is working diligently alongside federal, state, and local partners to achieve this objective. Here are three ways they are making a difference:
Protecting Critical Habitat
Defenders advocate for the protection of vital habitats such as wildlife corridors during public land management planning. They suggested increasing protections for northern spotted owl habitat corridors in the Northwest Forest Plan and urged the Forest Service to consider the effects of roads on wildlife, particularly species seeking new homes due to climate change-related habitat alterations.
Enhancing Wildlife-Vehicle Collision Reduction
Oregon and Washington each record at least 6,000 ungulate (hooved animals, such as deer) vehicle collisions annually. This figure likely undershoots the actual number when considering animals hit and moved out of sight. For instance, the Oregon Department of Fish and Wildlife estimates over 14.5 million animals are struck by vehicles every year in the state. These collisions not only pose a significant safety risk to humans and animals but also result in annual costs of $140 million and an average of 521 injuries and four deaths.
In the 2025 Oregon legislative session, Defenders worked alongside other organizations, advocating for the improvement of the existing wildlife-vehicle collisions reduction program. The bill, set to become law upon Governor Kotek's signature, includes measures like inter-departmental coordination, establishing a statewide advisory group, and requiring the Oregon Department of Transportation to consult with the Oregon Department of Fish and Wildlife to minimize wildlife corridor impacts when developing or maintaining transportation infrastructure.
In Washington, Defenders supports the Washington Habitat Connectivity Action Plan being prepared by the Washington Department of Fish and Wildlife in conjunction with the Washington Department of Transportation. Upon completion, this plan will identify priority locations for habitat connectivity across roadways and offer comprehensive data to conservation groups, aiding them in planning future projects.
Building Passages for Wildlife
Reconnecting habitats through roadways can take various forms, from large overpasses to simple tunnels. Some older structures can even be retrofitted to better facilitate wildlife movement, like at Janis Bridge on Highway 97 in northern Washington, where fencing was added to guide animals towards an existing structure. Crossing structures have proven successful in restoring movement corridors in the Northwest. For instance, the Snoqualmie Pass has seen over 25,000 animals utilizing the structure since its installation, while the Lava Butte Wildlife Crossing in Oregon led to a 90% reduction in deer-vehicle collisions.
While the Pacific Northwest has achieved numerous successes in this area, much work remains. Defenders is actively collaborating with local partners on wildlife crossing projects, including two in Oregon aimed at reducing wildlife-vehicle collisions and restoring connectivity across roadways that currently obstruct wildlife movement. Stay tuned for updates on these projects and Defenders' connectivity efforts in the coming months.
[1] Northwest Wetlands VIP Act - https://www.congress.gov/bill/117th-congress/house-bill/4582[2] Great Peninsula Conservancy - https://www.peninsulaconservancy.org/[3] Pacific Rivers - https://www.pacificrivers.org/[4] Washington Department of Natural Resources - https://www.dnr.wa.gov/[5] Oregon Coastal Program - https://www.oregon.gov/Coast/OCPlans/Pages/default.aspx
- To bolster wildlife movement in critical habitats, Defenders of Wildlife advocates for the protection of wildlife corridors during public land management planning, urging considerations of their impact on sensitive species and their role in accommodating species displaced due to climate change.
- In an effort to reduce wildlife-vehicle collisions, Defenders has worked alongside other organizations to improve Oregon's wildlife-vehicle collisions reduction program, aiming for better inter-departmental coordination, establishing a statewide advisory group, and requiring consultation with the Oregon Department of Fish and Wildlife to minimize impacts on wildlife corridors during transportation infrastructure development or maintenance.
- Recognizing the importance of reconnecting isolated habitats, Defenders is actively engaged in collaborative projects to build wildlife passages, such as overpasses, tunnels, and retrofitting existing structures, as showcased by the successful example at Janis Bridge on Highway 97 in northern Washington. These initiatives intend to restore movement corridors and facilitate wildlife connectivity across roadways in the Pacific Northwest.
