Assessing cumulative effects to support Indigenous-led ecosystem-based management in salmon watersheds

The management of cumulative effects from multiple pressures is a key challenge to achieving thriving watersheds for salmon and people. We documented and mapped cumulative effects across salmon watersheds of the Central Coast of what is now known as British Columbia, Canada, a region known for implementation of principles of ecosystem-based management and collaborative governance between Indigenous and Crown governments. Our approach is founded on the interests, knowledge, and values of Kitasoo Xai'xais, Nuxalk, and Wuikinuxv Nations. Working with Indigenous and non-Indigenous knowledge holders, we mapped over 30 pressures for salmon and other species important to salmon watersheds—temperate forest ecosystems subsidized by the annual return of salmon from the marine environment. We identified hotspots for cumulative pressures in major valleys including the Bella Coola, the Sheemahant, and the Kimsquit and demonstrate how single and multispecies approaches can change results. Hotspots of impact were contextualized with qualitative analysis and graphical illustrations describing complex changes to salmon including abundance, size, and behaviour and resulting impacts on people. Our work provides an example of how cumulative effects assessments that are underpinned by Indigenous values can shed light on knowledge gaps and opportunities for improving implementation of ecosystem-based management.