Climate Change: Assessing Vulnerability of Aquatic Ecosystems

Aquatic ecosystems throughout the western U.S. are likely to be impacted by the potential effects of climate change.  Impacts include altered thermal and hydrologic regimes, which will in turn affect the spatial and temporal distribution of water resources, habitats, and disturbance in aquatic ecosystems. Threats from reduced runoff, increased flow variability, increased temperature, increased wildfires, lost snowpack storage, and reduced vegetation cover affect water users and aquatic biota. The relative magnitude of the impacts will vary across and within watersheds depending on local settings and watershed characteristics.  The complex challenges posed by climate warming will require proactive, informed management if significant alteration of aquatic systems is to be avoided.  Availability of a new-computer based watershed analysis tool called NetMap and downscaled climate projections provides an efficient means to conduct vulnerability assessments of aquatic ecosystems with regard to climate change. Understanding the vulnerability of aquatic ecosystems at small scales is critical to the development of effective management and monitoring programs.  This will allow managers and decision makers to identify the vulnerability of watersheds to climate change and insights about the magnitude and location of the potential impacts of effects of climate change. We present examples of assessments from watershed in the Pacific Northwest of the U.S.