Projected Climate and Land Use Change Impacts on Aquatic Habitats of the Lower Colorado River Basin (Regional Assessment)

Previous climate change research for the Colorado River Basin has used down-scaled climate models to predict impacts to hydropower and the potential ability to meet mandated water releases. The Lower Colorado River Basin (LCRB) has one of the most imperiled fish faunas in the nation with about half of the native fish species listed as Threatened or Endangered under the Federal Endangered Species Act. Current water demands for agriculture and human consumption are only slightly less than long-term annual flows. Future projections based on climate change alone indicate decreased precipitation, increased temperatures, and lower annual runoff which will further stress this ecosystem that is experiencing among the highest human population growth rates in the nation. We refined the national fish habitat assessment using finer scale climate and land use change models combined with region-specific threats to predict impacts to aquatic habitats and the resulting responses of native and non-native fish communities in the LCRB. The goal of this project was to (1) project potential changes in the quality of aquatic habitat resulting from change in climate and land use, and (2) examine potential effects of projected climate and land use change on assemblage structure of fish communities.