Effects of altered precipitation regimes on wetland ecohydrology and biogeochemistry

湿地是景观中不可或缺的单元，为社会提供多种生态系统服务，包括重要的水文、生物地球化学、生态和社会功能。气候变化情景预测，北美五大湖区生长季降雨量减少，集中在更少、更强烈的极端事件中。水文是对湿地形态和功能的单一最大控制。降水分布的变化可能会从根本上改变湿地的水文过程。目前，我们对湿地生态水文学和生物地球化学对个别降水事件的动态响应知之甚少，因此无法准确预测湿地对降水状况变化的响应。本研究将致力于三个目标：1)调查近地表湿地垂直水文和生物地球化学过程对降水变化的响应；2)了解导致湿地侧向径流和养分转移动态变化的过程对降水的响应；3)通过植物-水-营养耦合动力学来确定温带湿地生态系统对降水变化的抵抗力和弹性。它将使用现场水文和地球化学分析相结合的方法，通过实验室和现场试验来研究植物生长、水分运动速度和水源面积。这项研究将提供明确的湿地响应范围和物种阈值，以适应三个地质区域内不同湿地类型与降水有关的气候变化，土地管理者将利用这些范围进行更知情的战略规划和预测。

Wetlands are integral units in the landscape, providing a number of ecosystem services to society, including important hydrological, biogeochemical, ecological, and societal functions. Climate change scenarios are predicting decreased growing season precipitation concentrated in fewer, more intense extreme events in the Great Lakes region of North America. Hydrology is the single greatest control on wetland form and function. A shift in the distribution of precipitation may fundamentally alter wetland hydrological processes. Presently we have very little knowledge on the dynamics of wetland ecohydrology and biogeochemistry in response to individual precipitation events, and therefore we cannot accurately predict wetland response to changing precipitation regime. This research will address three objectives: 1) to investigate the response of near-surface wetland vertical hydrological and biogeochemical processes to changes in precipitation; 2) to understand the processes that lead to changes in wetland lateral flow and nutrient transfer dynamics in response to precipitation regimes; and, 3) to determine the resistance and resiliency of temperate wetland ecosystems to precipitation change through coupled plant-water-nutrient dynamics. It will use a combined field hydrometric and geochemical analysis approach with both lab and field experimentation on plant growth and rates of water movement and water source area. This research will provide clear ranges of wetland response and species threshold tolerances to precipitation-related climate change across wetland type in three geologic areas that land managers will utilize for more-informed strategic planning and projecting.