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Urbanization and Massachusetts streams: Unpacking the biological effects of impervious cover

Stream surveying


January 2014 - June 2017


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.

Research Products and Activities


  • Roy, A.H., K.A. Capps, R. El-Sabaawi, K.L. Jones, T.B. Parr, A. Ramirez, R.F. Smith, C.J. Walsh, and S.J. Wenger. 2014. Global differences in urbanization and stream ecology: a synthesis. Joint Aquatic Sciences Meeting, 18-22 May 2014, Portland, OR.
  • Bentsen, C.N., A.H. Roy, and D.S. Armstrong. 2015. Accounting for biotic variability in urban streams: the role of local and landscape factors. New England Association of Environmental Biologists, 18-20 March 2015, Bartlett, NH.
  • Bentsen, C.N., A.H. Roy, and D.S. Armstrong. 2015. Accounting for biotic variability in urban streams: the role of local and landscape. Annual Meeting of the Society for Freshwater Science, 17-21 May 2015, Milwaukee, WI.
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Current Staff

Federal Staff: 95

Masters Students: 239

Phd Students: 143

Post Docs: 53

University Staff: 239

5 Year Summary

Students graduated: 701

Scientific Publications: 1949

Presentations: 4262



  • Allison RoyPrincipal Investigator
  • Catherine BentsenStudent
  • Christopher SmithStudent
  • Evan FerraroneStudent
  • Benjamin KnicelyStudent
  • Sam SillenStudent
  • Dave ArmstrongPrincipal Investigator
  • Robert SmithNon-PI Collaborator
  • Rachel KatzNon-PI Collaborator

Funding Agencies

  • Massachusetts Department of Environmental Protection


Cooperative Research Units Program Headquarters Cooperators

  1. U.S. Geological Survey