Effects of altered precipitation regimes on wetland ecohydrology and biogeochemistry

湿地是景观中不可分割的单元，为社会提供了许多生态系统服务，包括重要的水文、生物地球化学、生态和社会功能。气候变化情景预测生长期降水减少，集中在北美五大湖地区更少、更强烈的极端事件中。水文是控制湿地形态和功能的唯一最大因素。降水分布的变化可能从根本上改变湿地的水文过程。目前，湿地生态水文和生物地球化学对个别降水事件的响应机制知之甚少，因此无法准确预测湿地对降水变化的响应。本研究将围绕三个方面展开：1)研究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)了解湿地侧流和养分转移动态随降水变化的过程；3)通过植物-水-养分耦合动态确定温带湿地生态系统对降水变化的抵抗力和恢复力。它将采用实地水文和地球化学分析相结合的方法，对植物生长、水运动速率和水源面积进行实验室和实地试验。本研究将提供三个地质区域的湿地类型对降水相关气候变化的响应和物种阈值容忍的明确范围，土地管理者将利用这些数据进行更明智的战略规划和预测。

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.