Project Overview

SFEI, funded by, and in partnership with, the San Francisco Bay Regional Water Quality Control Board, evaluated current and future riparian ecosystem conditions and functions in the Petaluma River watershed to support a science-based approach to ecosystem management. Riparian ecosystems are affected by land use and human development alongside changing precipitation patterns and warming temperatures. We documented the current conditions and functions of riparian vegetation, assessed potential changes based upon climate modeling, and developed management actions to support riparian ecosystem resiliency to climate change. 

As the intersection between land and rivers, riparian ecosystems are a vital component of the Petaluma River watershed. An analysis of contemporary conditions revealed key riparian functions including channel shading, bank stabilization, fish and wildlife habitat, allochthonous inputs, and runoff filtration. 

Riparian ecosystems face multiple stressors including urban and agricultural development, which may be amplified by a changing climate. Declining low flows, increased precipitation variability, and increased high flows and sediment loads are projected throughout the watershed with some variability in timing and severity through the end of the century. These changes may lead to stressed riparian vegetation, reduced forested riparian width, and local declines in groundwater-dependent vegetation. 

Given the possible impacts to riparian vegetation and ecosystem functions, an evaluation of potential management actions was developed to support riparian ecosystem functions in the face of climate change, accounting for uncertainty. This framework provides a tool for landscape managers to plan for and maintain riparian ecosystem functions and achieve multiple benefits under a changing climate.