Cooperative Fish and Wildlife Research Units Program: Massachusetts
Education, Research and Technical Assistance for Managing Our Natural Resources

Many recent papers have synthesized the negative effects of urbanization and impervious cover on stream ecosystems. Although these responses to urbanization are widely documented and often strong, there are so many possible mechanisms that specific proximate causes are often difficult to distinguish. This is partially because both natural and anthropogenic factors influence the responses at different locations, but also due to a lack of understanding of specific stressors. The general relation between watershed impervious cover and most indicators of stream quality is often represented by a cone that progressively narrows with increasing impervious cover. The high variability in responses at low levels of impervious cover may be explained by factors unrelated or partially related to impervious cover, such as local in-stream habitat modifications, water-quality impairments, altered thermal regimes, and land-use history. Reach-scale habitat and water quality have been shown to be important stressors of biological assemblages. Thus, quantifying in-stream characteristics is important for predicting biotic responses to urbanization and understanding mechanisms of impairment. The goal of this research is to investigate fish and macroinvertebrate responses to regional, local, and in-stream environmental factors within narrow ranges of watershed impervious cover. Specific objectives are to: 1. Assess in-stream physical and chemical conditions (habitat, water quality, and temperature) in streams with similar watershed impervious cover 2. Identify landscape characteristics (natural and anthropogenic) at regional and local scales that predict in-stream physical and chemical characteristics 3. Identify linkages between landscape characteristics, in-stream physical and chemical characteristics, and fish and macroinvertebrates assemblages in streams with similar watershed impervious cover The development of landscape variables and predictive modelling in Objectives 2 and 3 will take place in conjunction with USGS New England Water Science Center (WSC). Overall, the research will help to better understand the mechanisms of impairment and stream response and recovery trajectories.