Collaborative Research: LTREB Renewal - River ecosystem responses to floodplain restoration

洪泛平原是指受水流影响的河流沿岸地区。洪泛平原为人们提供了许多重要的好处，但它们也容易受到洪水、污染和其他干扰等变化的影响。了解金属污染对河流生态系统长期变化的影响非常重要。该项目研究蒙大拿州上克拉克福克河（Upper Clark Fork River）十年来的变化，此前有一个大型项目修复了河流源头大面积采矿造成的植被和污染土壤。土地利用和废水处理的变化也改变了沿河的氮和磷浓度。自2013年以来，已经修复了近17公里的河流，并收集了三个核心数据集，这些数据集是在修复前几十年开始的。研究的长期测量和空间尺度为观察恢复实践中涉及的生态过程提供了机会。作为该项目的一部分，一些本科生和研究生接受了教育，数据向公众开放，并通过克拉克福克科学论坛与该河流系统的许多利益相关者分享结果。蒙大拿州上克拉克福克河的研究系统有几个独特的特点，使该项目能够取得重大的科学进展。首先，该系统接受了大量的金属输入，而这些金属已经停止使用。这使得调查生态系统动态随时间的变化，以响应这种停止。其次，研究人员在年代际尺度上密切观察了生态和生物地球化学响应，这是研究河流生态系统恢复缓慢过程类型的合适时间尺度。该项目生成的核心数据集包括：1)对有机质和沉积物金属的影响；2)沉积物金属上下游梯度的变化；3)春季洪水脉冲与夏季基流期间恢复河段洪泛区重新连接的代谢响应；4)与溶解有机质相互作用引起的金属生物有效性变化；5)河流恢复和未恢复部分氮、磷和溶解有机碳的测量。最终，该项目在大空间（200公里）和时间（年代际）尺度上调查河流生态系统的响应。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。

Floodplains are the areas alongside rivers that are affected by water movement. Floodplains provide many important benefits to people, yet they are also susceptible to changes such as flooding, pollution, and other disturbances. Understanding the effects of long-term changes in river ecosystems affected by metal pollution is extremely important. This project studies changes over ten years in the Upper Clark Fork River in Montana following a large project that restored vegetation and removed contaminated soil after damage from extensive mining in the river’s headwaters. Changes in land use and wastewater treatment are also altering nitrogen and phosphorus concentrations along the river. Since 2013, nearly 17 km of river has been restored and three core data sets have been collected, which were initiated decades before the restoration. The long-term measurements and the spatial scale of the study provides an opportunity to observe the ecological processes involved in restoration practices. Several undergraduate and graduate students are educated as part of this project, data are made available to the public, and results are shared with many stakeholders in this river system through the Clark Fork Science Forum.The study system of the Upper Clark Fork River in Montana, has several unique qualities that enable this project to make significant scientific advances. First, the system has received high inputs of metals that have since ceased. This enables investigation of the ecosystem dynamics over time in response to this cessation. Second, the investigators have closely observed ecological and biogeochemical responses over decadal timescales, which is the appropriate timeframe to study the types of slow processes involved in river ecosystem recovery. The project generates core data sets including: 1) influences on organic matter and sediment metals, 2) changes in upstream-downstream gradients in sediment metals, 3) metabolic responses to floodplain reconnection in restored reaches during the spring flood pulse vs. summer baseflow, 4) changes in metal bioavailability caused by interaction with dissolved organic matter, and 5) measurements of nitrogen, phosphorus, and dissolved organic carbon in restored and unrestored parts of the river. Ultimately, this project investigates river ecosystem responses over large spatial (200 km) and temporal ( decadal) scales.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.