Ordination of species biological and ecological traits by multiple correspondence analysis. (a) Distribution of modalities (black squares), for each trait, in the first factorial plane (F1–F2) of the analysis. Each modality square was positioned at the weighted average of the taxa positions (Fig. 2) representing this modality. The horizontal numbers in italics indicate the correlation ratio of the trait with the first axis (F1) while vertical ones indicate the correlation ratio of the trait with the second axis (F2). (b) Eigenvalues histogram.