Structure and productivity of streams in urbanized landscapes

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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.