Structure and productivity of streams in urbanized landscapes

加拿大各地的城市化压力正在增加，水文变化加上营养物和污染物的分散负荷现在被认为是对自来水的主要威胁。拟议的研究将研究城市地区的土地利用与河流生态系统的结构和生产力之间的关系。这项研究对河流生态学的进步和制定管理策略以减轻人类活动对淡水系统的影响具有重要意义。从理论角度来看，本研究将进一步加深我们目前对河流食物网能量流动的理解：1)量化水文制度改变对藻类、无脊椎动物和鱼类生产力的影响；2)量化鱼类捕食对河流组合大小结构的影响。这项研究将建立模型，预测河流生物的丰度和生产力在土地开发时是如何变化的。这样的模型可以用来评估管理方案的有效性，以保护基于流域活动的河流环境中的生物群。社会对河流栖息地的关注通常只集中在脊椎动物群落上；这项研究应该表明鱼类和它们所食用的生物之间的重要联系，以及这种联系如何随着自然和强加的环境梯度而变化。

Urbanization pressures are increasing across Canada and hydrological alterations combined with diffuse loading of nutrients and contaminants are now recognized as the principal threats to running waters. The proposed research will examine the relationship between land use and the structure and productivity of stream ecosystems in urban areas. This research has implications both in terms of advancements in stream ecology and for developing management strategies to mitigate impacts of human activities on freshwater systems. From a theoretical perspective, this research will further our current understanding of energy flow in stream food webs by 1) quantifying the impact of altered hydrological regimes on productivity of algae, invertebrates, and fish, and 2) quantifying the impact of fish predation on the size structure of stream assemblages. The research will lead to models that predict how abundance and productivity of stream organisms change when land is developed. Such models can then be used to evaluate the effectiveness of management scenarios to protect biota in stream environments based on drainage basin activities. Societal concerns regarding stream habitat usually focus only on vertebrate communities; this research should show the important link between fish and the organisms they consume and how this varies along natural and imposed environmental gradients.