Water Economy of Neo-Tropical Savanna Ecosystems: The Impact of Hydraulic Lift, Partitioning of Soil Water and Changes in Land Use

University Of Hawaii, Honolulu

Investigators

Abstract

Abstract 00-75235 Goldstein Water economy of neo-tropical savanna ecosystems: The impact of hydraulic lift, partitioning of soil water and changes in land use Roots can directly affect the distribution and availability of water in the soil profile by hydraulically lifting water from deep soil layers to shallow soil layers where water may be limiting. Hydraulic lift can have a significant impact on the water cycle of dry tropical savannas, because deeply rooted trees can lift water to within 1 m of the surface where herbaceous plants are rooted. Current land-use practices are reducing the abundance of trees in Brazilian savannas, the second most extensive ecosystem in South America after the rain forests. Tree removal, and the associated reduction in hydraulic lift, may result in a substantial fraction of the deep soil water and nutrients being lost from ecosystem recirculation processes. This study will characterize the regulation of water in Brazilian savannas and evaluate the impact of hydraulic lift on the distribution of water in the soil, on total evapotranspiration and on partitioning of water consumption among woody and herbaceous plants. The results of this study will provide new insights on the nature of interactions between woody and herbaceous plants and on the consequences of current land management practices in tropical savanna ecosystems.