The relative impact of co-occurring stressors on the abundance of benthic species examined with three-way correspondence analysis

This paper presents a novel application of three-way correspondence analysis as a technique to analyse three-way contingency tables with abundance scores of several species. The example data analysis presented was taken from a previous mesocosm experiment and consists of a two-factor experimental design with physical disturbance and organic enrichment as factors, applied to sediment collected from the Oslofjord, Norway. The focus of the original research was to evaluate the influence of the two factors and their interactions on the abundance of the species present in the sediment. In the current paper we demonstrate that by using a three-way correspondence approach it is possible to undertake simultaneous analysis of the species, identifying and evaluating their relative sensitivity to the environmental factors thus adding additional insight than was possible in the original analysis. In particular, this new approach allowed even relatively scarce species to be included in the analysis and evaluated together with abundant species. This paper demonstrates how three-way correspondence analysis can be a useful analytical tool in teasing out effects and interactions from multi-factorial studies.