Collaborative Research: Quantifying feedbacks between fluvial morphodynamics and pioneer riparian vegetation in sand-bed rivers

合作研究：量化沙床河流中河流形态动力学与先锋河岸植被之间的反馈

• 批准号: 1024820
• 负责人: John Stella
• 金额: $ 20.57万
• 依托单位: SUNY College of Environmental Science and Forestry
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1024820&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantifying; feedbacks; between

In dynamic river ecosystems, riparian vegetation interacts with flow, sediment transport, and deposition, resulting in the coevolution of channel forms and vegetation communities. This project will develop a mechanistic and predictive understanding of interactions and feedbacks between vegetation and stream-channel processes in sand-bed rivers. The project addresses two broad questions: (1) how do woody plants affect flow and sediment transport individually and collectively, and (2) how do flow and sediment transport processes influence the mortality of riparian plants with different morphological traits? Integrated laboratory, field, and computational approaches will be employed to represent varying scales of space, time, and ecosystem complexity. Flume and mesocosm experiments will test the effect of vegetation on flow and sediment transport around individual plants and within vegetation patches, and the reciprocal effect of flow on plant removal via scour and burial. In addition, a field-scale experimental facility, the Outdoor Stream Lab at the University of Minnesota, will be used to test feedbacks between vegetation patches and bathymetry, flow, and sediment transport in a meandering sand-bed channel. Field investigations in a regulated, sand-bed reach of the Bill Williams River in western Arizona with a mixed native and invasive riparian community will combine high-resolution measurements of topography and vegetation before and after dam-controlled flood events with high-flow measurements of hydraulics and sediment flux. Finally, computational modeling will be used to synthesize and generalize field efforts. Two-dimensional flow and sediment modeling, in which vegetation effects are parameterized based on laboratory and field observations, will evaluate feedbacks while simulating flow and vegetation management scenarios. In addition, a riparian vegetation patch-dynamics model will be adapted to analyze community-level implications of species' differences in scour and burial mortality over multiple generations. This investigation will advance our knowledge of the co-evolution of physical processes and vegetation communities along rivers and will also inform river restoration and management efforts. This study will specifically address questions related to designing water releases from dams to benefit ecosystems. It will explore how reductions in sediment supply downstream of dams affect riparian vegetation and it will examine the mortality mechanisms of cottonwood and willow, which are dominant and ecologically important species along rivers in many semi-arid regions. It will also aid in the management of tamarisk, an invasive shrub that is prevalent along rivers in the western United States. By integrating novel experimental facilities, field study areas, and modeling methods, the project will advance our ability to understand and manage fluvial ecosystems.

在动态河流生态系统中，河岸植被与水流、泥沙输移和沉积相互作用，导致河道形态和植被群落的共同演化。该项目将开发一个机制和预测性的理解植被和河道砂床河流过程之间的相互作用和反馈。该项目解决了两个广泛的问题：（1）木本植物如何影响流量和泥沙输运单独和集体，（2）流量和泥沙输运过程如何影响河岸植物的死亡率与不同的形态特征？综合实验室，现场和计算方法将被用来代表不同尺度的空间，时间和生态系统的复杂性。水槽和围隔实验将测试植被对单个植物周围和植被斑块内的水流和泥沙输运的影响，以及水流通过冲刷和掩埋对植物清除的相互影响。此外，明尼苏达大学的户外溪流实验室是一个现场规模的实验设施，将用于测试植被斑块与蜿蜒沙床水道中的水深、流量和沉积物输运之间的反馈。在亚利桑那州西部的比尔威廉姆斯河的一个受管制的砂床河段进行实地调查，该河段有一个混合的本地和入侵的河岸社区，将联合收割机在大坝控制的洪水事件前后对地形和植被进行高分辨率测量，并对水力学和沉积物通量进行高流量测量。最后，计算模型将被用来综合和概括实地工作。二维水流和沉积物建模将根据实验室和实地观察对植被影响进行参数化，在模拟水流和植被管理情景时将评估反馈。此外，河岸植被斑块动力学模型将适用于分析社区一级的影响物种的差异冲刷和埋葬死亡率在多个世代。这项调查将推进我们的知识的共同进化的物理过程和植被群落沿着河流，也将通知河流恢复和管理工作。这项研究将具体解决与设计大坝放水以造福生态系统有关的问题。它将探讨水坝下游沉积物供应的减少如何影响河岸植被，并将研究棉白杨和杨柳的死亡机制，这两种植物是许多半干旱地区沿着的主要和具有重要生态意义的物种。它还将帮助管理tamelik，一种入侵灌木，在美国西部的河流沿着很普遍。通过整合新的实验设施，实地研究领域和建模方法，该项目将提高我们理解和管理河流生态系统的能力。