Effects of floods on epilithon and benthic macroinvertebrate populations in an unstable New Zealand river

  • Scrimgeour G
  • Winterbourn M
  • 58


    Mendeley users who have this article in their library.
  • 111


    Citations of this article.


Temporal changes in epilithon biomass and benthic macroinvertebrate density were investigated in the Ashley River, a flood-prone river with an unpredictable discharge regime. Biomass, primary production and respiration of the epilithic community were highest in spring when filamentous algae were present and lowest following two large floods that occurred in close succession. Sixty invertebrate species were taken in benthic samples including 24 species of Trichoptera, 15 Diptera and 4 Ephemeroptera. Larvae of the mayfly Deleatidium (Leptophlebiidae) were numerically dominant and comprised up to 83 % of the fauna in any one month. Mean benthic invertebrate density was highest (9170-18 580 m-2) following long periods of low stable flow (< 30 m-3 s-1) and lowest (230 m-2) after a major flood (454 m-3 s-1). Reductions in benthic density occurred when flow exceeded about 30 m-3 s-1, the minimum discharge at which small cobbles are moved. Refuge seeking behaviours, flexible life histories and effective recolonization mechanisms enable the benthos of the Ashley River to persist and recover from frequent, temporally unpredictable disturbances. © 1989 Kluwer Academic Publishers.

Author-supplied keywords

  • Deleatidium
  • New Zealand
  • aquatic insects
  • epilithon
  • floods
  • river benthos

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Garry J. Scrimgeour

  • Michael J. Winterbourn

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free