Collaborative Research: WCR: Ecohydrology of semiarid woodlands: Role of woody plants in the water cycle

合作研究：WCR：半干旱林地的生态水文学：木本植物在水循环中的作用

• 批准号: 0233584
• 负责人: Jay Banner
• 金额: $ 16.63万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-01 至 2006-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0233584&HistoricalAwards=false
• 关键词: Collaborative; Research; WCR; Ecohydrology; semiarid

0233584SternExtensive areas of semiarid grasslands and savannas have been converted into shrublands. There is a common, but untested, assumption that reducing shrub cover will have tangible and large-scale effects on streamflow and ground water recharge. Our study area is the Edwards Plateau of Texas, where coverage by juniper is extensive and hillslopes are composed of highly permeable and fractured limestone. Our research will answer basic questions about flow processes at multiple scales on these limestone hillslopes and better define how much, if any, of an increased water yield could result from shrub control. Large plot (3 m wide, 12 m long) rainfall simulation will be applied above the tree canopy to develop an understanding of water fluxes for a number of rainfall regimes. During a simulation event, we will continuously monitor overland flow, lateral subsurface flow, canopy interception, soil water, and transpiration. Three plot locations will be selected for simulation experiments: one on a steep rocky hillslope, one on flatter slopes with deeper soils, and a third site above a cavern. The cavern site is especially significant because we should be able to obtain a good estimate of recharge rates. In addition, a series of isotopic studies at the hillslope, catchment and watershed scale will be conducted with the goals of (1) differentiating soil water loss via evaporation versus transpiration (2) conducting hydrograph separation using naturally occurring strontium (Sr) and O isotopes and trace element concentrations and ratios (Sr/Ca and Mg/Ca), and (3) determining shrub water use of rainfall, surficial soil water, and deep storage, both seasonally and spatially. The proposed study is a highly interdisciplinary examination and promises to be the most comprehensive examination of the ecohydrology of semiarid scrublands.

0233584半干旱草原和稀树草原的区域已转换为灌木丛。 有一个常见但未经测试的假设，即还原灌木覆盖物将对水流和地下水充电具有切实而大规模的影响。 我们的研究区是德克萨斯州的爱德华兹高原，杜松的覆盖范围广泛，山坡由高度渗透性和破裂的石灰石组成。我们的研究将回答有关这些石灰岩山坡上多个尺度流动过程的基本问题，并更好地定义灌木控制可能导致的水产量增加的多少（如果有）。 大图（3 m宽，12 m长）将在树冠上方应用降雨模拟，以发展对水通量的理解，以实现多种降雨状态。 在模拟事件中，我们将不断监视陆上流动，侧面地下流动，盖层截距，土壤水和蒸腾。 将选择三个地点进行模拟实验：一个在陡峭的岩石山坡上，一个在较深的土壤上的斜坡上，一个在洞穴上方的第三个地点。 洞穴部位尤其重要，因为我们应该能够获得充电率的良好估计。 此外，将进行一系列在山坡，集水区和流域量表的同位素研究，以（1）通过蒸发与蒸腾作用（2）使用自然发生的Strontium（SR）和O i同进的含量元素浓度和比例（SR/CA/CA/CA/CA/CA），（3），（3）的目标分离水的目标（2），（2）降级（SR），以及（3）以及季节性和空间上的深层存储空间。拟议的研究是一项高度跨学科的检查，并有望成为对半干旱灌木丛生态水文的最全面的检查。