Landscape Connectivity in Washington State
By Ryan Moehring
The ability to travel between habitats is essential for the long-term survival of many wildlife species. Habitat connectivity ensures that animals are able to locate food, breed, migrate between seasonal habitats, and respond to environmental changes such as wildfires, drought, and flooding. Connectivity is also vital to important ecological processes such as seed dispersal and nutrient cycling.
However, human-induced pressures from transportation corridors, agriculture, and development have fragmented wildlife habitats and populations across the country. In an effort to proactively address these issues, a variety of conservation stakeholders formed the Washington Wildlife Habitat Connectivity Working Group (WHCWG). A voluntary public-private partnership between state and federal agencies, universities, tribes, and non-governmental organizations, the WHCWG’s mission is: “Promoting the long-term viability of wildlife populations in Washington State through a science-based, collaborative approach that identifies opportunities and priorities to conserve and restore habitat connectivity.”
To achieve this goal, members of the WHCWG launched the Washington Connected Landscapes Project (WCLP). The foundation of this project is a series of statewide scientific analyses that explore connectivity issues for current landscape conditions in Washington, as well as models for projected future conditions that incorporate variables such as climate change. These studies have produced linkage network maps, which demonstrate areas of suitable habitat for the studies’ 16 focal species, as well as landscape linkages connecting these habitats.
Although human activities are greatly impacted by state and national borders, neither landscapes nor animals observe these invisible boundaries. Appropriately, the WCLP analysis studies wildlife connectivity from a regional perspective, including neighboring areas in Oregon, Idaho, and British Columbia. This methodology ensures the study results will provide resource managers in the affected states and provinces with a standardized data platform from which to base their conservation plans.
The studies separated the focal species into three distinct “connectivity guilds,” because their ranges and vulnerabilities to habitat fragmentation were representative of those of most other terrestrial species across the state of Washington and neighboring areas. These species range from the relatively immobile western toad to animals with vast territories that rely heavily on habitat corridors, such as the wolverine and the American black bear. White-tailed jackrabbits, northern flying squirrels, mule deer, and the American badger were also included in the studies.
Beyond highlighting suitable habitat and associated linkages for these species, the studies also identified obstacles to wildlife movement. Of particular concern are major highway systems in Washington. Interstates 5 and 90, for example, not only divide animal habitat and inhibit species migration but also increase the likelihood of human-animal encounters and conflicts. The Washington State Department of Transportation, a member of the WHCWG, is using the analyses to inform their decision to implement structures that will enable wildlife to safely cross these structures (e.g., fencing, enlarged culverts, and wildlife overpasses).
The WCLP is funded, in part, by a grant from the Great Northern Landscape Conservation Cooperative (GNLCC), which has supported landscape connectivity work in the past. One such project, “Document Fine Scale Linkage Areas and Conservation Delivery in the Northern Rockies of U.S. and Canada,” shares many similarities with the WCLP, including the mapping of barriers to animal movement, such as highways, agriculture, and development.
“Funding landscape connectivity projects is a high priority for the Service and our partners in the Great Northern LCC,” said Stephen Guertin, Chairperson of the GNLCC and Regional Director of the U.S. Fish and Wildlife Service, Mountain-Prairie region. “Projects such as the WCLP provide wildlife managers and other decision makers with a science-based framework for addressing the many impacts of climate change and habitat fragmentation. Armed with this knowledge, resource managers can make informed decisions that will allow for continued development and economic growth, while preserving our nation’s wildlife resources.”