HR: 12:05h
AN: H42B-08    [Abstracts]
TI: Eco-Geomorphology of Arid Regions: Landform- Hydrology-Vegetation Interactions.
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: G.R.Willgoose@leeds.ac.uk
AF: Earth and Biosphere Institute, University of Leeds, School of Geography, Room 2.55, Leeds, LS2 9JT United Kingdom
AU: Hancock, G
EM: Greg.Hancock@newcastle.edu.au
AF: Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308 Australia
AB: The vegetation of arid and semi-arid regions is usually patterned, consisting of patches with high biomass cover interspersed within bare soil. These patterns play an important role in controlling erosion and landform evolution. We use a modeling framework that couples landform evolution and vegetation growth to explore hillslope-scale interactions between vegetation patterns and sediment movement in arid and semi-arid regions. The coupling and feedback effects between vegetation and landforms are controlled by the hydrology. That is, the partition between surface and soil water governs sediment transport rates and vegetation growth. The main process for water redistribution in semi-arid and arid areas is Hortonian overland flow and vegetation patterns play a key role in this redistribution by controlling infiltration rates and runon-runoff areas. The model reproduces the dynamics of banded vegetation patterns for mild slopes and stippled or spotted patterns for steeper areas. Banded patterns act as closed hydrological systems, with little outflow and sediment coming out of the system. The effect of spotted vegetation on erosion is more complex and depends on the connectivity of the bare soil areas. Modeling results showing strong feedbacks effects between vegetation, hydrology and geomorphic changes (associated with changes in erosion and sedimentation) for both banded and stippled vegetation patterns will be presented. Long-term hillslope evolution results for areas with banded vegetation closely reproduce the observed hillslope profiles for various Australian field-sites. The effects of climate variability at both short and long-term temporal scales are explored.
DE: 0545 Modeling (4255)
DE: 1815 Erosion
DE: 1825 Geomorphology: fluvial (1625)
DE: 1826 Geomorphology: hillslope (1625)
SC: Hydrology [H]
MN: Fall Meeting 2005