RDA triplots ordinating the macroinvertebrate samples from Lake Dres, its inlet (R1) and its outlet (R2). Percent values reported along with the RDA axes 1 and 2 indicate the explained proportion of total variance. Black vectors indicate significant explanatory variables retained by the backward selection in each sampling site; most representative macroinvertebrate groups are reported in the diagram with their abbreviated name (abbreviations listed in Tab. 1).