Drivers of Change in Estuarine-Coastal Ecosystems: Discoveries from Five Decades of Study in San Francisco Bay
Observations made in San Francisco Bay over the past half century illustrate ecosystem responses to six common drivers of change where land and sea meet: river damming, water management, introduction of nonnative species, sewage input, environmental policies, and multidecadal climate shifts. Responses to these drivers include changes in virtually everything that we measure: sediment supply, geomorphology, freshwater inflow, nutrient enrichment, urban contaminants, biological communities, and food web structure. Detection of these changes and discovery of their causes through environmental monitoring have been essential for establishing and measuring outcomes of environmental policies. The many time scales of variability and the multiplicity of interacting drivers place heavy demands on estuarine monitoring programs, but the San Francisco Bay case study illustrates why the imperative for monitoring has never been greater.