Fluvial geomorphology and the winter habitat of stream salmonids

该研究计划的长期目标是提高我们对控制溪流鲑鱼冬季栖息地的河流形态和过程的了解。砾石床河流通常可分为若干离散的沉积环节，每一环节的特点是粗泥沙聚集的节点，然后是底质的逐渐向下细化，以及与之相关的河道坡度的降低。由于沉积环节下游底质和坡度的变化与河道形态和水力学的变化有关，它们创造了一个水生生境类型的纵向序列，从环节头部的陡峭、快速流动和湍急的巨石床河道到下游末端的蜿蜒、缓慢流动、低坡度的沙质河道。在接下来的五年里，我将更仔细地研究沉积连接在控制砾石床河流中大西洋鲑鱼幼体冬季栖息地的时空分布方面的重要作用。拟议研究的具体目标是：(1)检验沉积联系对大西洋鲑鱼幼体冬季栖息地的时空格局产生强烈控制作用的假设；(2)检验沉积联系对河流冰类型的大范围分布施加强烈控制的假设；(3)调查鲑鱼PARR对河冰形成所造成的生境条件变化的响应；以及(4)评估锚冰对鲑鱼产卵底物间隙流动速度的影响。

The long-term objective of the research program is to improve our understanding of the fluvial forms and processes controlling the winter habitat of stream salmonid. Gravel-bed rivers can often be segmented into a number of discrete sedimentary links, each characterized by a node of coarse sediment recruitment followed by a gradual downstream fining of substrate and an associated reduction of channel slope. Because the downstream changes in substrate and slope along sedimentary links are associated with changes in channel morphology and hydraulics, they create a longitudinal sequence of aquatic habitat types moving from steep, fast flowing and turbulent boulder bed channels at the head of links to meandering, slow-flowing, low-gradient sand channels at the downstream end. Over the next five years, I will investigate more closely the important role of sedimentary links in controlling the spatial and temporal distribution of juvenile Atlantic salmon winter habitat in gravel-bed rivers. The specific objectives of the proposed research are: (1) To test the hypothesis that sedimentary links exerts a strong control on the spatial and temporal pattern of juvenile Atlantic salmon winter habitat, (2) To test the hypothesis that sedimentary links exerts a strong control on the large-scale distribution of river ice types, (3) To investigate the response of salmon parr to the changing habitat conditions created by the formation of river ice, and (4) To asses the effect of anchor ice on the interstitial flow velocities of salmonid spawning substrates.