HR: 09:45h
AN: B51A-07    [PDF]
TI: Assessing the role of spatial pattern in governing ecohydrological interactions and vegetation dynamics in semi-arid savannas.
AU: Shugart, H H
EM: hhs@virginia.edu
AF: University of Virginia, Department of Environmental Sciences, Charlottesville, VA 22903 United States
AU: * Caylor, K K
EM: kcaylor@princeton.edu
AF: Princeton University, Department of Civil and Environmental Engineering, Princeton, NJ 08540 United States
AU: Scanlon, T M
EM: tscanlon@princeton.edu
AF: Princeton University, Department of Civil and Environmental Engineering, Princeton, NJ 08540 United States
AU: Rodriguez-Iturbe, I
EM: irodrigu@princeton.edu
AF: Princeton University, Department of Civil and Environmental Engineering, Princeton, NJ 08540 United States
AB: The spatial pattern of vegetation is both a cause and effect of variation in resource availability in semiarid ecosystems. At landscape to regional scales, climatic and geologic constraints on soil moisture and nutrient availability are primary determinants of vegetation structural pattern in semiarid ecosystems. Similarly, at local to landscape scales, the patchy vegetation structural mosaic serves to redistribute the availability of soil moisture and nutrients in ways that have important consequences for structural dynamics and community composition. A coupled energy and water balance approach was previously used to simulate the effects of large tree canopies on soil moisture and water stress across a series of sites spanning a regional moisture gradient in southern Africa. Results from the model indicate that tree canopies serve to reduce soil moisture stress of under canopy vegetation in the middle of the rainfall gradient, while at the dry end of the rainfall gradient the effect of tree canopies on soil moisture is dependent on the amount of rainfall received in a given growing season. These findings are used within a modeling framework to assess the relationship between vegetation pattern and subsequent structural dynamics of mixed tree/grass ecosystems in southern African savannas. Special attention is given to the potential for woody vegetation encroachment in southern African savannas under varying levels of climatic change and altered land tenure.
DE: 1600 GLOBAL CHANGE (New category)
DE: 1851 Plant ecology
DE: 1866 Soil moisture
DE: 1878 Water/energy interactions
SC: Biogeosciences [B]
MN: 2003 Fall Meeting