Untangling the relationships among climate, prey and top predators in an ocean ecosystem

摘要

Successful ecosystem-based conservation of marine resources can benefit from quantitative indicators of ecosystem productivity, particularly if such indicators quantify and incorporate the relationships between physical and biological components of the ecosystem simultaneously. Despite widespread explorations of relationships between physical processes particularly important to the ocean system (e.g. wind indices, advection and retention of coastal waters, sea surface temperature, coastal sea level and the temporal aspects of these factors) and resulting biological responses, explicit understanding of mechanistic connections often remains elusive. We use path analysis and partial least squares regression to visualize and quantify links between biological and physical components in the California Current ecosystem and to predict reproductive success at 3 trophic levels. We examine the applicability of this approach using a hierarchical pattern of environmental indices, relationships previously described in the literature and quantitative measures of zooplankton, fish and seabird productivity. We show that each trophic level and community production can be described using environmental and biological data in a manner that provides a comprehensive evaluation of physical and biological connectivity and mechanisms. Importantly, our approach to modeling an ecosystem represents a practical middle ground between simple correlative methods typically employed and a perhaps unattainable complete mechanistic understanding of all physical and biological mechanisms regulating variability in reproductive success.