HR: 0800h
AN: H51H-0869    [Abstracts]
TI: Vegetation Dynamics And Soil Moisture: Consequences For Hydrologic Modeling
AU: * Guardiola-Claramonte, M
EM: maiteg@email.arizona.edu
AF: Department of Hydrology and Water Resources, 1133 E James E. Rogers Way, Tucson, AZ 85721, United States
AU: Troch, P A
EM: patroch@hwr.arizona.edu
AF: Department of Hydrology and Water Resources, 1133 E James E. Rogers Way, Tucson, AZ 85721, United States
AB: Current global population growth and economical development accelerates land cover conversion in many parts of the world. Introducing non-native species and woody species encroachment, with different water demands, can affect the partitioning of hydrological fluxes. The impacts on the hydrologic cycle at local to regional scales are poorly understood. The present study investigates the hydrologic implications of land use conversion from native vegetation to rubber. We first compare the vegetation dynamics of rubber (Hevea brasiliensis), a non- native specie in Southeast Asia, to the other main vegetation types in the study area. The experimental catchment, Nam Ken (69km ²), is located in the Xishuangbanna Prefecture (21 °N, 100 °E), in the south of Yunnan province in South China. From 2005 to 2006, we collected continuous records of 2 m deep soil moisture profiles in four different land covers (tea, secondary forest, grassland and rubber), and measured surface radiation in tea and rubber canopies. Our observations show that root water uptake by rubber during the dry season is controlled by the change of day-length, whereas water demand of the native vegetation starts with the arrival of the first monsoon rainfall. The different root water uptake dynamics of rubber result in distinct depletion of deeper layer soil moisture. Traditional evapotranspiration and soil moisture models are unable to simulate this specific behavior, thus a different conceptual model is needed to predict hydrologic changes due to land use conversion in the area.
DE: 1804 Catchment
DE: 1807 Climate impacts
DE: 1813 Eco-hydrology
DE: 1834 Human impacts
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2007 Fall Meeting