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Title: RIPARIAN VEGETATION STRUCTURE INFLUENCES GROWING SEASON CARBON AND WATER EXCHANGE IN A SEMIARID WATERSHED 1607

Author
item POTTS, D. - UNIVERSITY OF ARIZONA
item Scott, Russell - Russ
item HUXMAN, T. - UNIVERSITY OF ARIZONA

Submitted to: Ecological Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/18/2004
Publication Date: 8/9/2004
Citation: Potts, D.L., Scott, R.L., Huxman, T.E. 2004. Riparian vegetation structure influences growing season carbon and water exchange in a semiarid watershed. In: Proceedings of the Ecological Society of America Abstracts, August 1-5, 2004, Portland, Oregon. 2004 CDROM.

Interpretive Summary: We compared data from a network of three eddy-covariance towers within a semiarid watershed to address the role of riparian vegetation structure in the linkage between ecosystem carbon and water exchange. Towers were located in a riparian grassland, a riparian savanna and a riparian woodland along the San Pedro River in southeastern Arizona, U.S.A. Analysis of 2003 growing-season data suggests that the frequency and magnitude of ecosystem carbon and water exchanges is most tightly linked at the grassland site. Furthermore, ecosystem carbon and water exchange is the most decoupled at the woodland site where the deep-rooted, dominant over-story species, Prosopis velutina, has access to abundant alluvial groundwater. A dynamic linkage of carbon and water exchanges in the riparian woodland during the growing-season reflects the onset of mid-summer convective storms associated with the North American monsoon. This research highlights the complex interaction between growing-season precipitation, plant-available alluvial groundwater and riparian vegetation structure in governing ecosystem carbon and water balance in this semiarid watershed.

Technical Abstract: We compared data from a network of three eddy-covariance towers within a semiarid watershed to address the role of riparian vegetation structure in the linkage between ecosystem carbon and water exchange. Towers were located in a riparian grassland, a riparian savanna and a riparian woodland along the San Pedro River in southeastern Arizona, U.S.A. Analysis of 2003 growing-season data suggests that the frequency and magnitude of ecosystem carbon and water exchanges is most tightly linked at the grassland site. Furthermore, ecosystem carbon and water exchange is the most decoupled at the woodland site where the deep-rooted, dominant over-story species, Prosopis velutina, has access to abundant alluvial groundwater. A dynamic linkage of carbon and water exchanges in the riparian woodland during the growing-season reflects the onset of mid-summer convective storms associated with the North American monsoon. This research highlights the complex interaction between growing-season precipitation, plant-available alluvial groundwater and riparian vegetation structure in governing ecosystem carbon and water balance in this semiarid watershed.