Effects of pollution on holdfast macrofauna of the kelp Ecklonia radiata :discrimination at different taxonomic levels

Non-metric multidimens~onal scallng (MDS) ordinations were conducted at 5 main taxonomic levels and 1 mixed level (corresponding to malor fauna1 groups) for community data from kelp holdfasts sampled across a gradient of domestic effluent at Coffs Harbour, New South Wales Australia All plots showed separation of close outfall sites from controls Two-way nested analys~s and pairwise compansons of locations using non-parametnc randomisation tests (ANOSIM) indicated that differences between the close outfall location and controls were significant at all taxononuc levels In contrast the effect due to sites within locations, although significant up to order was not significant for analyses at the muted class and phylum levels These observations support the hypothesis that anthropogenic effects moddy community structure at higher taxonomic levels than natural environmental vanables Consequently, s t u d ~e s of impact that focus on higher taxa may be more readily interpretable than those conducted at the species and family levels analysis of coral community response to the 1982-83 El Nino in the Thousand Islands. Indonesia.