Conservation Northwest / September 23, 2022 / Cascade to the Olympics, Connect Habitat, Update Work

Research reveals wildlife habitat connectivity hot spots along Interstate 5

By Cascades to Olympics Program Manager Brian Stewart and Cascades to Olympics Program Intern James Blacklaw

Since 2010, Conservation Northwest (CNW) is a committed partner and champion of the Washington Wildlife Habitat Connectivity Working Group (WWHCWG). The working group is composed of leading experts in the field of habitat connectivity and modeling in the Pacific Northwest (PNW). Their latest modeling work focuses on the southwestern and coastal regions of Washington, identifying hot spots along Interstate 5, US 101, US 6, and SR 8. Wildlife corridors and landscape permeability along these, and even more roads throughout the region.

Southwest Washington is a unique and rare Pacific Northwest landscape. It boasts the second largest river system in the state, multiple mountain ranges, national parks and forests. He is considered one of the most biodiverse and wettest areas in Washington state. The area is also home to many endangered species and some of the region’s most iconic species, including salmon, moose and cougars. Additionally, Southwest Washington is ancestral home to many diverse Indigenous communities, providing ecosystem services that sustain local tribes, families, businesses, and livelihoods.

Historically, this landscape was resilient to natural stressors, but today, unfortunately, the region is vulnerable to human activities, including climate change, increasing development and urban expansion, and changing land use. We are facing unprecedented threats that are heavily impacted by These threats continue to undermine the many thriving systems that sustain the prosperity of this land and its people. It must have the best available science to develop future-oriented adaptive management strategies that are relevant to today’s context while being flexible enough to account for , which is why we have focused our modeling efforts on the creation, restoration, and protection of resilient landscapes and ecosystems through the lens of habitat connectivity, protection, and sustainable infrastructure development. Using this framework will reduce developmental stressors, provide opportunities for wildlife to move safely so they can adapt to climate change, and protect carbon sequestering corridors and key habitat patches. I think it’s the best way to do that. Our goal is to eventually install wildlife-specific transverse structures on the highways and roads identified in the model.

Collectively, the WWHCWG used expert opinion, ground data, and scientific literature to develop models representing six different habitats in the region. To achieve this, the group decided to select endemic terrestrial species that could serve as proxies for other species associated with the same habitat type. For example, we chose the cougar as a surrogate for the generalist species and the semi-riparian habitat beaver, mt. Beaver for mid-altitude and mid-seed stage habitats, fisher for older growth, and western squirrel for oak forest meadows. Additionally, a landscape integrity model (naturalness) was utilized to take advantage of the ‘intactness’ of the landscape in this region. Finally, these models were superimposed to create a composite model. This shows where most of a species’ connectivity needs overlap with those of other species.

This data can be used to locate and prioritize feasibility studies for eventual implementation of wildlife connectivity projects. Including restoration, wildlife crossing structures on roads, habitat conservation, protection and more. Such landscape-level considerations have multiple benefits for people and wildlife. It makes roads safer, landscapes more transparent, people safer, and saves money.It’s a mythical victory, victory, victory, victory, victory.

The biggest takeaways from this report are for Washington’s major state highways. First, Interstate 5 (I-5) is a major obstacle for wildlife. However, our model identified his three priority areas of I-5 that require further study and where cross-structures may be most effective. CNW’s Cascades to Olympics program manager used different methods to locate the exact same location on his I-5 in his 2019 senior thesis, validating both works. Unfortunately, the northern, southern, and middle junctions of Interstate 5 are possibly the last remaining fortifications along the intrastate corridor. With development progressing at a breakneck pace, time is running out and it is imperative that action be taken to capitalize on the findings. Second, Highways 8, 10, and 12 are significant barriers for species to travel between his Chehalis Basin and the Olympic Peninsula. Several potential links have also been identified along these highways.

All in all, we are happy to participate and participate in such a very difficult group effort. CNW is proud to offer the knowledge and experience of Cascades to Olympics Managers. He has been studying I-5 for nearly six years now and is the first investigator to assess his I-5’s permeability to wildlife. CNW will leverage this connection to validate and implement the science developed for the region. We are passionate about continuing this exciting and important work.

The next big thing in West Coast Habitat Connection projects, planning, and implementation is finding ways to move wildlife safely above or below I-5 in southwestern Washington.

For more information on the Cascades to Olympics program, please visit our website.