The use of prediction to assess macroinvertebrate response to river regulation
- Cite this article as:
- Armitage, P.D., Gunn, R.J.M., Furse, M.T. et al. Hydrobiologia (1987) 144: 25. doi:10.1007/BF00008048
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A technique, which uses environmental data to predict the macroinvertebrate fauna of running water sites, was used to investigate the response of faunal communities to flow regulation below a set of upland reservoirs in Great Britain. Five variables (total oxidised nitrogen, alkalinity, chloride, substratum type and site distance from stream source) were used to predict family presence and abundance at 30 regulated sites. The predictions were compared with the observed fauna recorded in samples taking in spring, summer and autumn. Of the 37 commonly occurring families 22 showed statistically significant trends. Twelve of these occurred at lower abundances than predicted and the effect was greatest in Heptageniidae, Simuliidae, Elminthidae, Perlodidae and Rhyacophilidae. Ten families were more more abundant than predicted and these included Polycentropodidae, Sphaeriidae, Sialidae and some groups of chironomids and oligochaetes. Fifteen families showed no significant trends. Most families showed little difference in the observed and expected frequency of occurrence in the 30 sites but Taeniopterygidae and Perlidae amongst others occurred at less than the expected number of sites and Hydridae, Prodiamesinae and Muscidae occurred more commonly than expected. These faunal responses are discussed in relation to environmental changes arising from flow regulation. The possible uses of the predictive technique in simulating and assessing the effects of regulation on downstream fauna are outlined.