Ref ID : 1131
Susan E.K. Cook; Quest for an index of community structure sensitive to water pollution. Environmental Pollution 11:269-288, 1976
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This paper reviews indices summarising benthic macroinvertebrate data and uses samples from an unpolluted lenthic stream to test their sensitivity to various environmental parameters. The Shannon-Wiener index, the most commonly used quantitative measure in the U.S.A, is evaluated against the qualitative Chandler score. The latter was originally designed for a lotic stream in Scotland but has subsequently been shown to be of wider application. Values of both indices and a modification of the Chandler score were regressed with the following environmental variables: temperature, total alkalinity, conductivity, per cent oxygen saturation, dissolved oxygen content, biochemical oxygen demand and coliform count. The Shannon-Wiener index is primarily sensitive to total alkalinity which may be an indirect measure of stream productivity. The dominance index of Berger & Parker (1970) is highly correlated with the Shannon-Wiener index and is very much simpler to use. The Chandler modification, in contrast, is well correlated with the coliform count and BOD, parameters which are associated with pollution. Quantitative and qualitative measures are thus sensitive to different aspects of benthic macroinvertebrate community structure and are affected differentially by environmental perturbations such as pollution. The Shannon-Wiener index emerged as a very imprecise, if not dubious, pollution index. The modification of the Chandler score, in contrast, gives the most reliable continuous assessment.