Environmental quality of a stream can be better predicted by phylogenetic than by taxonomic diversity

Different indices of taxonomic diversity (TD) and phylogenetic diversity (PD) of the macrobenthos were compared to determine the efficient predictors of environmental quality (EQ) in different types of watercourses in Poland. Archived data of 864 samples of benthic invertebrates identified to the family level were analysed on the basis of linear and non-linear multiply regression. The strengths of the correlations between two measures of EQ:BMWPpl (British Monitoring Working Party score system, Polish modification) and MMI (Multimetric Macroinvertebrate Index) and the values of taxonomic richness and three well-known TD indices: Shannon, Margalef and J' Evenness were compared to those for values of three PD indices, based on taxonomic distinctness. Taxonomic richness and all PD indices correlated more strongly with both measures of EQ than all TD indices. Correlations with both types of diversity indices were visibly stronger for BMWPpl when compared with MMI. We suggest that analysed indices of PD, especially MDis (mean phylogenetic distance between families in a sample), are related with EQ strongly enough to be taken into account as potential metrics in selection procedures of biological assessment.