Access to natural substrates in urban streams does not counter impoverishment of macroinvertebrate communities

a comparison of engineered and non-engineered reaches

D. J. Reid*, C. Tippler

*Corresponding author for this work

    Research output: Contribution to journalArticle

    3 Citations (Scopus)

    Abstract

    Urban streams are degraded through multiple mechanisms, including severely altered flow regimes, elevated concentrations of waterborne contaminants, removal of riparian vegetation and the loss of a mosaic of heterogeneous aquatic habitats. Engineering of urban stream reaches using concrete is a widespread and extreme case of deliberate alteration of flow regimes and concomitant habitat simplification. To assess the effect of such engineering practices on stream ecosystems, we compared aquatic macroinvertebrate communities from concrete-lined engineered urban reaches, non-engineered urban reaches with natural substrates and reference reaches flowing through minimally disturbed forested subcatchments and with natural substrates, in the Sydney metropolitan region, Australia. The communities from all urban reaches were impoverished and distinctly different from more diverse communities in forested reference reaches. Despite low aquatic habitat heterogeneity, engineered urban reaches had very high abundances of Diptera and some other tolerant taxa. Diptera and/or Gastropoda were dominant in non-engineered urban reaches. Multivariate community structures were dissimilar between the urban reaches and forested reference reaches and between non-engineered and engineered urban reaches. However, the low family-level richness and SIGNAL scores in both urban reach types indicated they were severely ecological impaired, whether engineered or not. Most macroinvertebrate taxa in the regional pool that were hardy enough to inhabit urban reaches with natural substrates were also present in nearby concreted reaches. The results add weight to the growing evidence that in urban landscapes, regional-scale changes in water quality and flow regimes limit the establishment of diverse macroinvertebrate communities, which cannot be addressed through the provision of increased reach-scale habitat heterogeneity.

    Original languageEnglish
    Article number8
    Pages (from-to)1-15
    Number of pages15
    JournalWater, Air, and Soil Pollution
    Volume230
    Issue number1
    DOIs
    Publication statusPublished - Jan 2019

    Keywords

    • Urban stream
    • Concrete channel
    • Stormwater
    • Macroinvertebrates
    • Reach-scale management

    Cite this