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Bedford, David R ¹ ; Small, Eric E ²

¹ Department of Geological Sciences, University of Å·ÃÀ¿Ú±¬ÊÓƵ
² Department of Geological Sciences, University of Å·ÃÀ¿Ú±¬ÊÓƵ

Spatial patterns of ecohydrologic properties allow examination of spatial interactions between hydrologic, ecologic, soil, and climate parameters. We use the spatial patterns of ecohydrologic properties to understand plant strategies to increase their water supply.

Small-scale measurements of surface microtopography (n~8,000 total), infiltration rate (n~400), soil texture (n~800), and vegetation have been made on six 100 m2 plots along a transect within the Sevilleta. The transect is located in shrubland and spans a hillslope and alluvial fan landform.

Preliminary results show that ecohydrologic properties are strongly dependant on vegetation and landscape position. Microtopography, infiltration rates, soil fines, and organic matter are higher under vegetation and decrease away from plant centers. Vegetation cover decreases; while the number of species increases, microtopography increases, with higher slope and drainage area. Microtopography, infiltration rate, and texture are all spatially correlated with vegetation pattern. The magnitude of geostatistic correlations and correlation distances both tend to decrease with increasing slope and drainage area.

Our data suggests that vegetation is responsible for much of the spatial variability in ecohydrologic properties. These properties are anisotropic, suggesting that slope-driven processes are also driving variation. Thus vegetation interacts dynamically with processes such as overland flow and erosion.