The relationships between environmental quality (BMWPpl and MMI) and phylogenetic diversity of leeches, expressed by the values of mean phylogenetic distance (MPD − white bars) and quadratic entropy (QE − grey bars) for groups of sites differed in terms of biocoenotic type (IV − a, b; V − c, d; VI − e, f). First quartile, third quartile and maximal value are shown on the bar and median values are presented as the circles. Vertical lines separate moderate and extreme values of EQ, while horizontal lines mark percentile 0.9 of both indices. Statistical significance between sites with moderate and extreme values of EQ is presented in Table 2.