LTREB: Collaborative Research - River ecosystem responses to floodplain restoration

蒙大拿州西部的上克拉克福克河留下了采矿污染和洪水的遗产。2013年启动了一项耗资2亿美元的河流生态恢复计划，并将持续20年。20多年来，国家机构和科学家收集了关于这条河的水化学、河底生长的藻类以及280公里河流沿线金属污染的丰度和分布的数据。这些核心数据集捕捉了一条严重受损的河流的历史，但负责这些数据集的大部分资金和人员随着时间的推移而流失。这项研究扩展并利用了这些长期监测数据，以解决河流的物理形态和生物过程将如何应对营养物质丰度变化和大规模泛滥平原恢复的同时影响。对河流过去和未来动态的比较为研究人员提供了一个机会，以解决生态学的基本理论，以应对在范围内罕见的系统操纵。这项研究将为理解适用于未来河流项目的大规模泛滥平原恢复的影响提供一个框架。教育和外展活动将包括为本科生实习生建立研究培训计划，指导美洲原住民本科生REU参与者，与克拉克·福克流域教育计划合作，以及在克拉克福克河沿岸的农村社区开发一个设有五年级科学课程的项目。修复工作将包括清除含有大量金属的泛滥平原土壤、将泛滥平原降至原来的高度，以便在洪水期间更容易与河流相连，以及在最接近污染源的河流泛滥平原上重建超过70公里的植被。这项研究将产生数据，以检验恢复将改变河流生态系统结构和功能的假设，因为恢复反应将反映泛滥平原尾矿的移除，重建泛滥平原的连通性，并减少对上游的营养输入。此外，这项研究还将测量排水网络中上游河段的变化将如何改变下游河段可用的能量和材料的纵向梯度。这项研究将重新建立对沉积沉积物中无机磷和氮浓度、海底有机质储量和可回收金属总量的监测。将对无机氮的同位素特征进行纵向调查，以跟踪不断变化的营养来源。历史监测将得到加强，利用荧光光谱学对溶解有机碳的浓度和组成进行跟踪，并进行实验，以解决碳组成如何影响金属生物有效性的问题。潜水式自主系泊仪器的使用将提供高分辨率的pH、氧气和二氧化碳测量，用于生成河流新陈代谢(初级生产和呼吸)的模型，以便将功能变化与改变的化学和生物环境联系起来。这些努力将共同提供机会，在与景观恢复相称的时间和空间尺度上解决克拉克福克河上游的生态变化问题。

The Upper Clark Fork River in western Montana has a legacy of mining pollution and flooding. A $200 million-dollar ecological restoration of the river was initiated in 2013 and will continue for 20 years. For over 20 years, state agencies and scientists have gathered data on the river's water chemistry, the algae that grow on the river bottom, and the abundance and distribution of metal contamination along 280 km of the river. These core data sets have captured the history of a highly impaired river, but most of the funding and personnel responsible for these data sets have been lost over time This research extends and capitalizes on these long-term monitoring data to address how the river's physical forms and biological processes will respond to the simultaneous influences of changing nutrient abundance and large-scale floodplain restoration. Comparisons of past and future dynamics of the river provide an opportunity for the researchers to address fundamental theories of ecology in response to a system manipulation that is rare in scope. The research will provide a framework for understanding effects of large-scale floodplain restoration that will be applicable to future river projects. Educational and outreach activities will include the establishment of a research training program for undergraduate interns, mentoring Native American undergraduate REU participants, working with a the Clark Fork Watershed Education Program, and developing a project with 5th grade science classes in rural communities along the Clark Fork River. Restoration will include removal of metal-laden floodplain soils, lowering of the floodplain to its original elevation where it will be more readily connected to the river during flooding, and re-vegetation of over 70 km of the river's floodplain closest to contaminant sources. This research will generate data to test the hypothesis that restoration will change the river ecosystem structure and function because restoration responses will reflect removal of floodplain tailings, reestablished floodplain connectivity, and reduced nutrient inputs to upstream reaches. Additionally, the research will measure how changes to upstream reaches within the drainage network will alter longitudinal gradients in energy and materials available to downstream river segments. The research will re-establish monitoring of inorganic phosphorus and nitrogen concentrations, benthic organic matter stocks, and total recoverable metals in depositional sediments. Longitudinal surveys of isotopic signatures for inorganic nitrogen will be used to track changing nutrient sources. Historical monitoring will be augmented with tracking of dissolved organic carbon concentration and composition using characterization by fluorescent spectroscopy, along with experiments to address how carbon composition influences metal bioavailability. Use of Submersible Autonomous Moored Instruments will provide high-resolution measures of pH, oxygen, and carbon dioxide that will be used to generate models of river metabolism (primary production and respiration) in order to link functional changes to altered chemical and biological environments. Together these efforts will provide opportunities to address the ecological changes in the Upper Clark Fork River over a temporal and spatial scale commensurate with landscape restoration.