LTREB: Multi-scale effects of climate variability and change on hydrologic regimes, ecosystem function, and community structure in a desert stream and its catchment

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。由于沙漠中的气候和水密切相关，因此沙漠溪流非常适合用于观测自然气候变化和人为引起的气候变化的后果。在这里，研究人员建议研究河流生态系统结构如何随着多年的山洪暴发和干旱时期的不同频率和程度而变化，从而导致湿地植物丰度的损失或增加。河流生态系统结构向湿地植物主导的转变对生态功能的影响是重要的，但没有文献记载。这种变化的原因和后果将通过调查结构、监测河流化学、在冬春洪水后恢复期间比较湿地和无植被的河流，以及统计分析水文-生态系统关系来评估。一个跨学科团队将重新评估河流生态系统模型，并使用来自这条河流和其他河流的长期数据测试新模型。这项研究将促进对干旱区河流长期数据的综合，并促进对这些生态系统的理解，从而有助于建立多元生态系统状态稳定性的一般理论。分布式的研究生研讨会将给予学生使用长期数据库的经验，并促进协作互动。这一著名河流生态系统的数据库将延长至35年以上，并向科学和管理界开放，有可能在气候变化和人口增长的压力因素正在汇聚的高度变化的环境中为管理提供信息。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Because climate and water are intimately linked in deserts, desert streams are well suited for observing consequences of both natural climate variability and human-caused climate change. Here, researchers propose to study how stream ecosystem structure changes as variable frequency and magnitude of both flash floods and drought periods over many years cause losses or gains in the abundance of wetland plants. A shift in stream ecosystem structure to dominance by wetland plants affects ecological functions in important but undocumented ways. Both the causes and consequences of this shift will be assessed by surveying structure, monitoring stream chemistry, comparing wetland with unvegetated stream reaches during recovery following winter-spring flooding, and statistically analyzing hydrology-ecosystem relationships. An interdisciplinary team will reevaluate stream ecosystem models and test new models using long-term data from this and other streams. This research will promote synthesis of long-term data from aridland streams and advance understanding of these ecosystems in ways that can contribute to the general theory of stability of multiple ecosystem states. A distributed graduate seminar will give students experience with use of long-term databases and foster collaborative interactions. The database for this well-known stream ecosystem will be extended to more than 35 years and made available to the scientific and management community, potentially informing management in a highly variable environment where stressors of climate change and population growth are converging.