Compositional approach to the analysis of species abundance data

The investigation of species associations is a classical problem in ecology, in order to describe and predict environmental characteristics. In this contribution we apply the log-ratio approach to the analysis of species abundance data through the Aitchison geometry (Aitchison, 1986). The logratio transformations produce acceptable projections of the correlations among species in principal component space that will be used to analyze association among species. An application to a real dataset of the propose procedure is illustrated.