HR: 0800h
AN: H31G-0749    [Abstracts]
TI: Ecohydrologic Response of Vegetation Patterns to Climate Variability in Arid and Semi-arid Ecosystems.
AU: * Saco, P M
EM: patricia.saco@newcastle.edu.au
AF: School of Engineering The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia
AU: Willgoose, G
EM: garry.willgoose@newcastle.edu.au
AF: School of Engineering The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia
AB: In arid and semi-arid regions, the interaction and feedbacks between climate, soils, vegetation and topography gives rise to the emergence of distinct patterns of vegetation and surface water re-distribution. These patterns are associated with a spatially variable infiltration field characterized by low infiltration rates in the bare soil areas and high infiltration rates in the vegetated areas (that have improved soil aggregation and macroporosity). Here we use a modeling framework that couples evolving landforms, dynamic vegetation and hydrology to explore the dynamics of these patterns at the hillslope-scale. We analyze the spatial and temporal dynamics of soil moisture, runoff and erosion that is driven by the spatially variable infiltration rates associated with those patterns. We also analyze the effect of interannual rainfall fluctuations on the soil water balance, on the dynamics and temporal variability of the vegetation patterns, and on the hydrologic response of the hillslope. We run the model with different parameter choices to simulate the dynamics of grasses, shrubs, and coexisting grasses and shrubs for long term climate fluctuations. Our results show that the coexistence of grasses and shrubs in these patterns increases long term biomass production as compared to the results for the individual plant types, suggesting that the observed self-organized patterns maximize water use and biomass production. We further discuss the consequences for long term erosion and equilibrium profiles.
DE: 1719 Hydrology
DE: 1813 Eco-hydrology
DE: 1815 Erosion
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2007 Fall Meeting