Cooperative Agreement for affiliated Partner with the Colorado Plateau Cooperative Ecosystem Studies Unit

The USGS is offering a funding opportunity to a CESU partner for conducting riparian plant physiological experiments and a synthesis of existing data to evaluate how plant interactions are mediated by dam operations by using species occurring along the Colorado River between Glen Canyon Dam and Lake Mead (the Colorado River ecosystem, CRe) and historic data that includes ground-based monitoring data of riparian vegetation along the Colorado River in Arizona and broad-scale regional datasets. Both existing data and new data will be required to complete the research. While large monitoring datasets exist for the CRe, key relationships between hydropower derived flow patterns and plant communities are poorly understood. Additionally, plant interactions are likely altering how plant communities respond to changes in dam operations and these interactions have not been accounted for prior research. Daily fluctuating flows related to hydropower generation can alter riparian plant communities, but how these flows are promoting or hindering species in the CRe is difficult to disentangle from other key flow patterns (periods of high flows and lows flows) in field observations. Experiments are therefore necessary to examine how riparian plant species differ in their responses to daily fluctuating flows, thereby providing insight into which do better under hydropower conditions. Further, ten years of vegetation monitoring in the CRe suggest that the presence and influence of some plant species alter the plant communities observed in the field. These interactions could be altering how the plant community is responding to dam operations, prohibiting a clear understanding of how dam operations could be leveraged to improve vegetation resource conditions. Thus, two lines of research, conducting new experiments and modeling with existing data, are needed. The questions that underpin this research are:1.

Which plant species benefit or suffer from daily fluctuations created by a hydropower dam?2.

How do plant species interact with one another along a regulated river, and how are these interactions mediated by flow conditions?