Allan 2004 land use and stream ecosystems

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Allan, D.J. 2004. Landscapes and riverscales: the influence of land use on stream ecosystems. Annual Review of Ecological and Evolutionary Systems, vol. 35, pp.257-284.


  • Provides a literature review and synthesis about how land use at different scales affects stream ecosystem condition.
  • Suggests six mechanisms of land use influence: sedimentation, nutrient enrichment, contaminant pollution, hydrologic alteration, riparian canopy opening, loss of wood debris.
  • Defines four challenges in evaluating land use impacts:
    • Covariation of natural and human features--people alter landscapes in patterns that also reflect changes in landscape function.
    • Scales of influence relative to site: catchment, riparian buffer, reach buffer.
    • Nonlinearity
    • Legacy effects--where dramatic historical changes to ecosystem structure or process are still driving condition
  • Conclusions in relation to management are limited:
    • Complex indicator arrays may be more diagnostic than indices.
    • Reversion to historical conditions is usually not viable, and so we depend on BMPs, which require skillful application.
    • One size all management is unlikely to be as cost effective as solutinos tailored to context.