E x e c utive Su m ma r y

Wildlife habitat connectivity is crucial for the survival and well-being of many wildlife species, especially where human development has fragmented the natural landscape. Whatcom County, Washington has recognized the importance of preserving wildlife habitat connectivity alongside other critical areas such as wildlife habitat conservation areas, fish habitat conservation areas, and wetlands. However, Whatcom County has not yet formally identified critical areas for wildlife habitat connectivity conservation areas within the County’s geography.

This report by Wildlands Network describes a novel set of geospatial connectivity analyses that provide information about the current state of wildlife habitat connectivity in Whatcom County. We used multiple, complementary modeling methods to identify the largest remaining patches of wildlife habitat, the best connections between those habitats, the most likely migration paths for terrestrial wildlife, and the relative value of each part of the landscape for supporting wildlife habitat connectivity.

This information is intended to support Whatcom County’s efforts to identify important areas for wildlife habitat connectivity and designate critical connectivity areas for consideration under the County’s Critical Area Ordinance. These critical connectivity areas could help highlight important habitat connections in need of conservation, identify fragmented areas where habitat restoration could improve connectivity, and guide future development to areas where it would have the least negative impact on connectivity. We hope the greater conservation community will also use these maps to support their work to protect wildlife across Whatcom County and the surrounding landscape.

Wildlife habitat connectivity – the ability of a landscape to facilitate the movement of wildlife species across it – is critical for wildlife to thrive and ecosystems to function. Animals move to find resources, migrate across seasons, avoid dangerous disturbances, or find new mates and habitats. Even stationary species like plants and fungi move across generations as habitats shift and environments change. The ability to move through a connected landscape with intact habitat and limited human impact is necessary for many species to survive, thrive, and evolve. This is especially true in the face of the growing impacts of climate change, which will cause species’ ranges to shift. Fortunately, awareness of the importance of wildlife habitat connectivity and corresponding efforts to conserve and restore it are on the rise around the world.

Whatcom County, Washington has recognized the importance of wildlife habitat connectivity and identified the need for a connectivity analysis of their geographic area. The Critical Area Assistance Handbook recommended identifying and designating any lands essential for habitat connectivity (Ousley et al. 2003). Another report for the Whatcom County Critical Areas Ordinance noted that “Washington State Growth Management Act guidelines suggested that ‘Land essential for preserving connections between habitat blocks and open space’ be one of the identified habitat types to be designated as a fish and wildlife habitat conservation area” (Whatcom County Planning and Development Services, 2005). Despite these recommendations, Whatcom County has not yet identified critical areas for wildlife habitat connectivity.

Locating these critical areas will inform development planning under Whatcom County’s Critical Area Regulations, which include a stated goal to “maintain the natural geographic distribution, connectivity, and quality of fish and wildlife habitat and ensure no net loss of such important habitats” (Whatcom County Planning and Development Services, 2017). Critical Connectivity Areas should be considered alongside previously mapped features like Wildlife Habitat Conservation Areas (including streams), Floodplains and Frequently Flooded Areas, and wetlands during Critical Area Regulation reviews. In addition, maps of wildlife habitat connectivity in Whatcom County could support and inform local conservation and restoration efforts through the County’s Conservation Easement Program and other County and partner conservation programs. These maps could also guide implementation of the State Wildlife Action Plan, which is currently under revision. While several large-scale connectivity maps have been developed for the United States, none offer the level of local detail and resolution necessary for recognizing critical connectivity areas in the developing and actively managed areas of Whatcom County (McRae et al. 2016, Theobald et al. 2011, Belote et al. 2016, Barnett and Belote 2021). So, the Whatcom County Planning Department’s Natural Resources Division reached out to the Wildlands Network to support development of a connectivity map specifically for the County.

Wildlands Network is a non-profit conservation organization that seeks to reconnect, restore, and rewild North America for the benefit of all life. We are a science-driven organization specializing in connectivity analysis, conservation, and policy whose founders were among the vanguard of conservation ecology and connectivity science (e.g. Michael Soulé, considered one of the founders of conservation biology, John Davis, and Reed Noss). Whatcom County asked Wildlands Network to analyze and visualize the current state of wildlife habitat connectivity in the County to help identify critical connectivity areas, increase conservation and restoration of connectivity, and guide development in the county to maintain ecosystem connectivity and minimize connectivity loss.

Whatcom County is situated in the northwestern corner of Washington State between Skagit County to the south, Okanogan County to the east, British Columbia to the north, and the Salish Sea (Puget Sound) to the west. The actual jurisdictional area of Whatcom County covered by the Critical Area Ordinance – not including other municipalities, federal land, and tribal nations – covers less than half of the land area of the county proper (Figure 1). This jurisdictional boundary contains the bulk of the county’s urban development, human population, major roads, and working lands (including agriculture and forest lands), all of which contribute to fragmentation of wildlife habitat and loss of connectivity. The land here includes coastal lowlands, abundant wetland and riparian areas, rich valleys, and mountainous foothills. The eastern part of the county, dominated by the Cascade Mountain Range that runs south-to-north through Washington into Canada, is almost entirely federally owned and managed by the U.S. Forest Service or the National Park Service.

Although this connectivity analysis was designed to serve Whatcom County, we expanded our study area beyond the County borders. This was both because we did not want edge effects at the county line (due to the analysis not incorporating information about the land outside it) and because to wildlife and ecosystems, these borders are mostly arbitrary. Instead, we decided to define our study area as the combined area of three of Washington’s Water Resource Inventory Areas (WRIAs 1, 3, and 4). These management units are defined by major drainage basins including the Nooksack basin, the Upper and Lower Skagit basins, the Sumas River basin, the Sauk basin, and the Strait of Georgia basin. Their combined area covers all of Whatcom County, most of Skagit County to the south, some of Snohomish County, and part of British Columbia to the north (Figure 2). Using this expanded study area allowed us to create maps that look beyond the borders of Whatcom County, are more relevant to current landscape management scales (the WRIAs), and are ecologically meaningful.