Environmental Toxicology and Chemistry · 1999 · 77 citations · 0 references
Natural SciencesEcologyEnvironmental SciencesCommunity EcologyEcotoxicologyEnvironmental Impact AssessmentCommunity-level EffectsEcotoxicology Of InsecticidesEnvironmental AnalysisEnvironmental Data AnalysisTemporal Community DynamicsCommunity-based ResponseEnvironmental Effects On ResponseEnvironmental Effects On Species ResponseLong-term Exposure EffectsRedundancy AnalysisTime-varying Treatment Effects
In this paper a novel multivariate method is proposed for the analysis of community response data from designed experiments repeatedly sampled in time. The long-term effects of the insecticide chlorpyrifos on the invertebrate community and the dissolved oxygen (DO)–pH–alkalinity–conductivity syndrome, in outdoor experimental ditches, are used as example data. The new method, which we have named the principal response curve method (PRC), is based on redundancy analysis (RDA), adjusted for overall changes in community response over time, as observed in control test systems. This allows the method to focus on the time-dependent treatment effects. The principal component is plotted against time, yielding a principal response curve of the community for each treatment. The PRC method distills the complexity of time-dependent, community-level effects of pollutants into a graphic form that can be appreciated more readily than the results of other currently available multivariate techniques. The PRC method also enables a quantitative interpretation of effects towards the species level.