Identifying conservation priority estuaries in British Columbia with a graph-based measure of landscape connectivity

Predicting and ranking ecologically important estuaries supports estuary conservation efforts in British Columbia. Connectivity, an indicator of ecological importance, is not a component of rankings created to date by conservationists. I used graph theory to describe estuarine connectivity for three migratory birds: Dusky Canada Geese, Western Sandpipers, and White-winged Scoters and ranked estuaries based on their maintenance of connectivity. I developed seven metrics that quantified the importance of each estuary for connectivity at local and coastal scales. I computed the metrics and ranked estuaries separately for each species. Rankings were spatially proximal across species and indicated connectivity hot spots, i.e., collections of high-ranking estuaries within a restricted geographic area. E mpirical observations of the focal species at connectivity hot spots verify that the graph model and connectivity metrics can predict important estuarine stopovers. These connectivity rankings are useful for prioritizing estuaries for conservation and for guiding future research.