Sensitivity of a semi-arid riparian ecosystem to climatic variability in the southwestern United States

Authors: DIXON, M. - University Of South Dakota; STROMBERG, J. - Arizona State University; MEIXNER, T. - University Of Arizona; HOGAN, J. - University Of New Mexico; Goodrich, David - Dave

Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/1/2010
Publication Date: 9/15/2010
Citation: Dixon, M.D., Stromberg, J., Meixner, T., Hogan, J.F., Goodrich, D.C. 2010. Sensitivity of a semi-arid riparian ecosystem to climatic variability in the southwestern United States. Proc. 8th International Symposium on Ecohydraulics 2010, Seoul, Korea, September 12-16, 2010. (CD-ROM), 8p.

Interpretive Summary: Climatic change will have strong impacts on rivers and their adjacent riparian zones. In the southwestern United States, conservation and restoration of riparian habitats has become a priority for resource management agencies and conservation groups as these areas are biodiversity hot spots in arid and semi-arid landscapes. Given the dependence of human societies on water, these areas are impacted by water resource development, both of ground and surface waters, with the potential for conflict heightened under an increasingly arid climate and a growing human population. Using the San Pedro River (Arizona, USA) as our primary case study, we review findings from two decades of research on the relationships between riparian vegetation, climate, channel changes, and both surface and subsurface hydrology. The distribution, composition, and productivity of riparian vegetation are dependent on both surface flows and groundwater dynamics. Floods, both as a source of water and as an agent of disturbance, are important for establishing and maintaining riparian vegetation. While influenced by both floods and groundwater dynamics, riparian vegetation also exerts important feedbacks via evapotranspiration and influences on bank stability and channel change.

Technical Abstract: Climatic change will have strong impacts on riverine ecosystems and their associated riparian zones. In the southwestern United States, conservation and restoration of riparian habitats has become a priority for resource management agencies and conservation groups, and these areas are biodiversity hot spots within the arid/semi-arid landscape. Given the dependence of human societies on water, these areas are impacted by water resource development, both of ground and surface waters, with the potential for conflict heightened under an increasingly arid climate and a growing human population. Riparian vegetation and landscapes are likely to be most strongly influenced by climate-linked changes in surface and groundwater hydrology. Using the San Pedro River (Arizona, USA) as our primary case study, we review findings from two decades of research on the relationships between riparian vegetation dynamics, climate, geomorphic change, and both surface and subsurface hydrologic processes. The distribution, composition, and productivity of riparian vegetation are dependent on both surface flows and groundwater dynamics. Floods, both as a source of water and as an agent of ecological disturbance, are important for driving riparian vegetation dynamics. While influenced by both floods and groundwater dynamics, riparian vegetation also exerts important feedbacks on these processes, and on entire system response, via evapotranspiration and influences on bank stability and channel dynamics.