Collaborative Research: RAPID: Determining the Impacts of a Combined Historical Watershed and Regional Drought on Coastal Louisiana Wetland Ecohydrology

气候变化造成的间歇性干旱事件通过地下水位下降和地表水和地下水盐碱化威胁沿海湿地植被。先前的观察一直无法直接联系植被响应干旱驱动的盐水入侵。缺乏联系使得建立湿地变化的整体模型具有挑战性，这些模型可以在时间和空间上以敏感的方式准确捕捉干旱的影响。鉴于湿地生态系统服务对沿海保护计划和区域经济（如渔业和生态旅游业）的影响过大，需要改进现有的知识体系。该项目将利用路易斯安那州和美国中西部持续的历史性干旱以及密西西比河水位低的情况，调查干旱强度、持续时间和发生与沿海湿地植被反应和水文条件之间的关系。这些发现可以纳入路易斯安那州正在进行的沿海湿地管理和规划，路易斯安那州正在投入大量资源解决这个问题。路易斯安那州拥有美国40%的沿海湿地，这意味着项目的发现将为研究地点以外的许多地区提供深入了解，包括墨西哥湾沿岸的其他低坡度海岸线。历史性的当地干旱与历史性的低水位和河流流量的同时发生，为咸淡水沼泽和沿海淡水森林的高土壤盐度事件奠定了基础，它们不适应这些条件。这项研究的目标是确定干旱驱动的地下水和盐度变化对沿海湿地植被的影响，测量地下水位和盐度恢复到背景水平需要多长时间，并调查靠近河流是否保护一些湿地免受相关压力。在森林和沼泽地，将在浅威尔斯井中安装电导率-温度-水位传感器。将在实地考察期间和通过遥感对植被的健康和丰富程度进行定性评估。该项目正在利用来自国家维护的连续监测站的历史数据。这些数据可用于预测建模，以确定当前干旱将如何影响未来的植物反应，导致沼泽和墨西哥湾沿海森林损失的恶化。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

Episodic drought events caused by climate change threaten coastal wetland vegetation through the lowering of the water table and salinization of surface and groundwater. Prior observations have been unable to directly link vegetation response to drought-driven saltwater water intrusion. The lack of connection makes it challenging to generate holistic models of wetland change that can accurately capture droughts effects in a sensitive way over time and space. Improving the current body of knowledge is needed given the disproportionately large impact wetland ecosystem services have on coastal protection schema and regional economies (e.g. fisheries and eco-tourism). This project will leverage the ongoing, historic droughts in Louisiana and the Midwestern United States, and low Mississippi River water levels, to investigate the relationship between drought intensity, duration, and onset and coastal wetland vegetative response and hydrologic conditions. The findings can be incorporated into ongoing coastal wetland management and planning in Louisiana, which is investing significant resources into the problem. Louisiana holds 40% of all coastal wetlands in the United States which means that project findings will yield insight for many areas beyond the study sites, including other low sloping coastlines bordering the Gulf of Mexico.The co-incident of a historical local drought with historically low water levels and flow in the river sets the stage for a high soil-salinity event in brackish and fresh marshes and coastal freshwater forests, which are not adapted to these conditions. The goals of this research are to determine the effect of drought-driven groundwater and salinity changes on coastal wetland vegetation, measure how long it takes the groundwater level and salinity to return to background levels, and investigate if proximity to the river protects some wetlands from associated stresses. At both forest and marsh sites, conductivity-temperature-water level sensors will be installed in shallow wells. Vegetation will be qualitatively assessed for health and abundance during site visits and by remote sensing. The project is leveraging historical data from continuous monitoring stations maintained by the state. These data can be used for predictive modeling to determine how present-day drought will affect future plant responses, leading to worsening of marsh and coastal forest loss in the Gulf of Mexico.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.