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、土壤水分配和土地利用变化的影响

• 批准号: 0075235
• 负责人: Guillermo Goldstein
• 金额: $ 48.93万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-11-01 至 2002-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0075235&HistoricalAwards=false
• 关键词: Water; Economy; Neo; Tropical; Savanna

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.

摘要00-75235Goldstein新热带稀树草原生态系统的水经济：水力升力、土壤水分配和土地利用变化的影响根系可以通过水力作用将水从深层土层提升到水可能受到限制的浅层土层，从而直接影响土壤剖面中水的分布和可用性。水力提升可以对干燥热带稀树草原的水循环产生重大影响，因为根深蒂固的树木可以将水提升到草本植物扎根的地表 1 m 范围内。目前的土地利用做法正在减少巴西稀树草原的树木数量，而巴西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升力的减少可能会导致大部分深层土壤水和养分在生态系统再循环过程中流失。本研究将描述巴西稀树草原的水调节特征，并评估水力升力对土壤中水分布、总蒸散量以及木本和草本植物耗水量分配的影响。这项研究的结果将为木本植物和草本植物之间相互作用的性质以及热带稀树草原生态系统当前土地管理实践的后果提供新的见解。