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

气候变化引起的间歇性干旱事件通过降低地下水位和使地表水和地下水盐碱化来威胁滨海湿地植被。先前的观测无法将植被响应与干旱驱动的盐水入侵直接联系起来。由于缺乏联系，很难建立湿地变化的整体模型，以一种敏感的方式准确捕捉干旱随时间和空间的影响。鉴于湿地生态系统服务对沿海保护方案和区域经济（如渔业和生态旅游）的巨大影响，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正在发生的历史性干旱，以及密西西比河的低水位，调查干旱强度、持续时间和开始与沿海湿地植被反应和水文条件之间的关系。研究结果可以纳入路易斯安那州正在进行的沿海湿地管理和规划中，该管理和规划正在投入大量资源来解决这个问题。路易斯安那州拥有美国所有沿海湿地的40%，这意味着项目发现将为研究地点以外的许多地区提供洞察力，包括与墨西哥湾接壤的其他低倾斜海岸线。历史上的地方干旱与历史上的低水位和河流流量的同时发生，为不适应这些条件的咸淡沼泽和淡水沼泽以及沿海淡水森林的高土壤盐度事件奠定了基础。本研究的目的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，测量地下水水位和盐度恢复到背景水平所需的时间，并调查是否靠近河流保护一些湿地免受相关压力。在森林和沼泽地区，将在浅井中安装电导率-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度进行定性评估。该项目利用了由国家维护的连续监测站的历史数据。这些数据可以用于预测建模，以确定当前的干旱将如何影响未来的植物反应，导致墨西哥湾沼泽和沿海森林损失的恶化。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

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.