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

新热带稀树草原生态系统的水经济：水力提升、土壤水分分配和土地利用变化的影响根系通过水力提升，将水分从深层土壤层提升到水分有限的浅层土壤层，从而直接影响土壤剖面中水分的分布和有效性。水力提升可以对干燥的热带稀树草原的水循环产生重大影响，因为深深扎根的树木可以将水提升到草本植物扎根的表面1米以内。目前的土地使用做法正在减少巴西稀树草原的树木数量，稀树草原是南美洲仅次于雨林的第二大生态系统。树木的移除，以及相关的水力提升力的降低，可能会导致很大一部分深层土壤水分和养分从生态系统再循环过程中流失。这项研究将表征水在巴西稀树草原的调节，并评估水力提升对土壤中水的分布，总蒸散量和木本和草本植物之间的水消耗分配的影响。这项研究的结果将提供新的见解之间的相互作用的性质木本和草本植物和热带稀树草原生态系统目前的土地管理措施的后果。

Abstract00-75235GoldsteinWater economy of neo-tropical savanna ecosystems: The impact of hydraulic lift, partitioning of soil water and changes in land useRoots 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.