The Role of Salmon in Resource Subsidies, and Challenges for Ecosystem-Based Management

Salmon have been shown to have variable impacts on freshwater and terrestrial ecosystems.  Although they import nutrients to these systems through release of eggs and decomposition of their carcasses, they also scour substrates and cause localized export of nutrients.   Ecosystem-based management requires an understanding of these processes, but so far we lack a clear synthesis to quantify relationships between numbers of salmon and their wide-ranging ecosystem impacts.  Our research on species ranging from biofilm to birds in the Great Bear Rainforest of coastal British Columbia shows the role of salmon in freshwater and terrestrial communities, as well as the mediating effects of habitats.  These findings, combined with results of other published studies, reveal general quantitative relationships between salmon populations and key ecosystem attributes.  This reveals opportunities as well as challenges for incorporating salmon into ecosystem-based management.