Redundancy Analysis (RDA) of ciliate abundance data during (A) spring (day 1–day 42) and (B) summer (day 1–day 43) colonization period in the Lake Sakadaš. The plots show the distribution of dominant ciliate taxa along the first and second RDA axes in relation to the statistically significant environmental parameters: AW (ash weight − inorganic matter in periphyton), Chl a P (chlorophyll a in periphyton), COND (conductivity), D (lake depth), DW (dry weight − inorganic + organic matter in periphyton), DWL (Danube water level), POM (particulate organic matter), SD (water transparency), TN (total nitrogen), WT (water temperature). Dominant ciliate taxa codes (explained in Fig. 4) are italicized. Open circles indicate days of colonization.