Community level analysis of ecotoxicological field studies: I. Biological monitoring

A number of multivariate techniques including nonmetric clustering, nonmetr ic multidimensional scaling, and principal components analysis were used to analyze data from a farm pond study in which the pyrethroid insecticide cy permethrin was aerially applied adjacent to the water body. The techniques were used to investigate the effects upon benthic and emerging macroinverte brate communities prior to, during, and following application. Hydrosoil cy permethrin residue was strongly correlated with changes in community compos ition, and Diptera were found to be most affected by the perturbation. Howe ver, any deleterious effect upon chironomid communities was transient, with Chironomidae larvae rapidly recovering after application. The study illust rates how multivariate techniques can aid in the interpretation of biologic al monitoring studies in which an adequate control pond is unlikely to be a vailable.