Precipitation Controls of Carbon and Nitrogen Cycles in Arid-Semiarid Ecosystems

干旱半干旱生态系统碳氮循环的降水控制

• 批准号: 0917668
• 负责人: Osvaldo Sala
• 金额: $ 79.94万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0917668&HistoricalAwards=false
• 关键词: Precipitation; Controls; Carbon; Nitrogen; Cycles

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Although precipitation is assumed to be the major control of the production of plants in arid and semiarid regions, annual precipitation explains only 20-40% of grass and shrub production variability among years. This failure suggests that researchers are not accounting for key mechanisms that control the ability of arid ecosystems to track fluctuations in precipitation. Yet increased fluctuations are a prominent feature of climate predictions in arid regions. This project puts forward four hypotheses to explain observed lags in ecosystem response to changing precipitation, and tests them by altering patterns of total precipitation and precipitation variability, with and without nitrogen manipulation. These manipulations, together with the model analysis, will help determine the cause and magnitude of lags in the ecosystem response to precipitation. Results from this project will contribute to understanding the effect of climate change on carbon sequestration, forage production and the process of shrub encroachment, which are very important for stakeholders of the southwestern U.S., ranging from cattle ranchers to city authorities worrying about water supplies and ecosystem services. A demonstration project will be established in partnership with a nonprofit organization that provides award-winning science education to more than 12,000 children and 4,500 adults annually in southern New Mexico and western Texas. In addition, the project will develop web sites and outreach materials to transmit findings beyond the university.

该奖项是根据2009年的《美国回收和再投资法》（公法111-5）资助的。尽管假定降水是干旱和半干旱地区植物生产的主要控制，但年度降水仅解释了年份中的20-40％的草和灌木生产变化。这种失败表明，研究人员没有考虑控制干旱生态系统跟踪降水波动的能力的关键机制。然而，增加的波动是干旱地区气候预测的重要特征。该项目提出了四个假设，以解释生态系统对变化降水的反应中观察到的滞后，并通过改变和不进行氮操纵的情况来改变总降水和降水可变性的模式来对其进行测试。这些操作以及模型分析将有助于确定生态系统对降水响应中滞后的原因和幅度。该项目的结果将有助于理解气候变化对碳固换，草料生产和灌木侵占过程的影响，这对于美国西南部的利益相关者来说非常重要，从牛牧场主到担心供水和生态系统服务的城市当局。示范项目将与一个非营利组织合作建立，该组织每年在新墨西哥州南部和西德克萨斯州为12,000多名儿童和4,500名成人提供屡获殊荣的科学教育。此外，该项目将开发网站和外展材料，以将发现传递到大学之外。