Urbanization & biotic integrity

Numerous studies have examined relationships between land use variables and stream biota, and shown that urban-related land uses can significantly alter stream assemblages.

Land use variables considered include % urban land (in the catchment and in riparian areas), % impervious surface area (total and effective), road density and other measures of urbanization.

Biotic responses associated with these land use variables include (but are not limited to):

ALGAE

• ↑ abundance or biomass
  [Roy et al. 2003, Taylor et al. 2004, Busse et al. 2006]
• other changes in assemblage structure (e.g., changes in diatom composition)
  [Winter & Duthie 2000, Sonneman et al. 2001, Newall & Walsh 2005]

BENTHIC MACROINVERTEBRATES

• ↓ total abundance, richness or diversity
  [Morley & Karr 2002, Moore & Palmer 2005, Walsh et al. 2007]
• ↓ EPT (Ephemeroptera, Plecoptera, Trichoptera)
  [Morley & Karr 2002, Roy et al. 2003, Riley et al. 2005, Walsh 2006]
• ↑ abundance of tolerant taxa
  [Jones & Clark 1987, Walsh et al. 2007]
• other changes in assemblage structure (e.g., changes in functional fedding groups)
  [Stepenuck et al. 2002, Smith & Lamp 2008]
• ↓ quality of biotic indices
  [Kennen 1999, Morley & Karr 2002, DeGasperi et al. 2009]

FISHES

• ↓ abundance, biomass, richness or diversity
  [Wang et al. 2003a, Bilby & Mollot 2008, Stranko et al. 2008]
• other changes in assemblage structure (e.g., changes in reproductive guilds)
  [Stepenuck et al. 2002, Roy et al. 2007, Helms et al. 2009]
• ↓ quality of biotic indices
  [Snyder et al. 2003, Miltner et al. 2004, Morgan & Cushman 2005]
• ↑ biotic homogenization (replacement of more endemic, specialist fishes with more broadly distributed, generalist fishes)
  [Scott 2006 (Fig 2), Walters et al. 2009]

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