Discussion

Water Resource Inventory Areas 1, 3, and 4 - which include most of Skagit County and parts of Snohomish County and British Columbia. Taken together, our Linkage Mapper and Omniscape results present a robust picture of the current state of structural wildlife habitat connectivity on this landscape. Our Wildlife Habitat Connectivity Value index provides an easy-to-understand snapshot of connectivity value designed to support land use decisions.

This work was supported by, and partially modeled after, previous work in southwest Washington by researchers for the Washington Wildlife Habitat Connectivity Working Group (Gallo et al. 2019). That analysis also used Linkage Mapper and Omniscape together to provide a nuanced picture of wildlife habitat connectivity and considered the benefits and drawbacks of each approach.

Linkage Mapper is a powerful toolbox for creating clear, intuitive connectivity maps based on user-defined habitat cores and the heterogenous landscape between them. However, creating those habitat cores and deciding what counts as “core habitat” for wildlife can be difficult, especially for a broad structural connectivity analysis like this one. We decided to use a relatively inclusive definition of habitat cores – in this case, unbroken patches of “natural” landcover 100 acres or larger – but in reality, these cores may have wildly different value for wildlife. A 100-acre core in the suburbs of Bellingham is almost certainly poorer habitat for most species than a 5,000-acre core in the remote Cascades, for example. One useful approach to this problem would be to think of those smaller cores as stepping stones along connectivity corridors in the fragmented west of Whatcom County, it can’t purposes of this project, though, identifying corridors in the west, where continuing development and fragmentation threaten connectivity, is a more urgent need.

In contrast to Linkage Mapper, Omniscape provides a full picture of wildlife habitat connectivity across the entire landscape. This both removes the need to define habitat cores and gives us insight into relative connectivity value within the habitat core areas from Linkage Mapper. The biggest downside to Omniscape is simply that it can be confusing. The complex web of connections can be potentially overwhelming for land managers or planners seeking to use this map to identify critical connectivity areas, especially without the cores to show what habitats are being connected. Plus, to echo the authors of the WWHCWG study, deciding what counts as a habitat core can be an important step for examining the goals and assumptions of our connectivity analysis.

Because of the strengths and weaknesses of these different approaches, Wildlands Network has provided Linkage Mapper and Omniscape maps together to provide a complete and nuanced picture of wildlife habitat connectivity in Whatcom County and its surrounding watersheds. We then boiled down several aspects of wildlife habitat connectivity into an accessible, easy to understand Connectivity Value index. We hope that these maps will inform land managers and planners about the current state of wildlife habitat connectivity and empower them to conserve and restore connectivity for the benefit of all of Whatcom County’s wildlife into the future.