Dendogram of Regression Tree Analysis (RTA) showing the relationships between the environmental predictors and mixotrophs relative biovolume (MRB). COD (chemical oxygen demand), dissolved inorganic nitrogen (DIN), bicarbonate (HCO₃⁻), pH, chloride and water color. N is the number of selected lakes per tree node. The pie chart indicates proportion of biovolume from the three trophic strategies. Green = Photo-osmotrophic phytoplankton (autotrophy), light purple = obligate-osmotrophic phytoplankton (osmotrophy) and dark purple = phagotrophic phytoplankton (phagotrophy). RMSE = 0.22, R² = 0.51.