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河流形式和控制河流鲑鱼冬季栖息地的过程的理解。砾石河床的河流通常可以被分割成若干个离散的沉积环节，每一个环节的特征都是一个粗泥沙补充的节点，随后是一个逐渐向下游细化的基岩和河道坡度的相应减少。由于沿沉积链的下游基材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栖息地类型的纵向序列，从链接头部的陡峭、快速流动和湍流的卵石床河道，到下游末端蜿蜒、缓慢流动、低梯度的沙河道。在接下来的五年里，我将更密切地研究沉积联系在控制砾石河床大西洋鲑鱼幼鱼冬季栖息地时空分布中的重要作用。拟议研究的具体目标是：(1)验证沉积联系对大西洋鲑鱼幼鱼冬季栖息地时空格局的强烈控制假说；(2)验证沉积联系对河冰类型大尺度分布的强烈控制假说；(3)研究鲑鱼伴侣对河冰形成造成的栖息地条件变化的响应。(4)评估锚冰对鲑鱼产卵基质间质流速的影响。

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.