Spatial coherence of ecosystem indicators across the Scotian Shelf, Canada

Abstract

Marine ecosystems are subject to increasing pressure from climate change and a range of anthropogenic activities such as fishing, aquaculture, tourism, and energy extraction that take place at multiple spatial scales. Understanding the complex interplay between spatially and temporally varying marine ecosystem dynamics is needed for long-term sustainable management. Implementation of ecosystem-based management (EBM) relies in part on ecological indicators that link science to policy while also providing a means to explore ecosystem response to change and to assess progress toward management and policy goals. EBM requires reliable and robust indicators at commensurate spatial scales to assess the ecological impacts of pressures and management actions. We evaluated the spatial and temporal behaviour of ecological indicators at multiple spatial scales to answer three main questions: (i) Is the spatial and temporal resolution of current data collection in the Scotian Shelf fine-grained enough to detect changes in key indicators at the strata level? (ii) How closely do fluctuations in time series at the survey strata level match those at the larger spatial scales? (iii) Is there spatial coherence across survey strata and indicators? We developed a process for examining the reliability and robustness of ecological indicators at differing spatial scales to show that scale does indeed matter.