LTREB: Collaborative research - River ecosystem responses to floodplain restoration

蒙大拿州西部的上克拉克福克河有采矿污染和洪水的遗留问题。 2013年启动了一项耗资2亿美元的河流生态恢复计划，将持续20年。20多年来，国家机构和科学家收集了有关河流水化学、生长在河底的藻类以及沿着280公里金属污染物的丰度和分布的数据。这些核心数据集已经捕获了一条高度受损的河流的历史，但负责这些数据集的大部分资金和人员都随着时间的推移而丢失了。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不断变化的营养物质丰度和大规模洪泛区恢复的同时影响。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，以应对范围内罕见的系统操作。这项研究将提供一个框架，了解大规模的洪泛区恢复，将适用于未来的河流项目的影响。教育和推广活动将包括为本科实习生建立一个研究培训计划，指导美国本土本科REU参与者，与克拉克福克流域教育计划合作，并在克拉克福克河沿着农村社区开发一个五年级科学课程项目。恢复工作将包括清除含金属的洪泛区土壤，将洪泛区降低到其原来的高度，以便在洪水期间更容易与河流相连，并在最靠近污染源的河流洪泛区70多公里处重新种植植物。这项研究将产生的数据来测试这一假设，恢复将改变河流生态系统的结构和功能，因为恢复反应将反映清除洪泛区尾矿，重建洪泛区的连通性，并减少营养物质输入上游河段。此外，该研究将测量排水网络内上游河段的变化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无机磷和氮浓度、底栖有机物存量和沉积物中可回收金属总量的监测。无机氮同位素特征的纵向调查将用于跟踪不断变化的营养源。历史监测将通过使用荧光光谱表征跟踪溶解的有机碳浓度和组成来增强，沿着实验以解决碳组成如何影响金属生物利用度。使用潜水自主系泊仪器将提供pH值、氧气和二氧化碳的高分辨率测量，这些测量将用于生成河流代谢（初级生产和呼吸）模型，以便将功能变化与改变的化学和生物环境联系起来。这些努力将提供机会，以解决生态变化在克拉克福克河上游的时间和空间尺度与景观恢复相称。

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.