F1 × F2 plane of CCA analysis showing 20 mayfly taxa, 10 study sites encompassing 31 microhabitats in Plitvice Lakes NP and nine selected environmental variables. Legend: Study sites (black circle symbols): IBR = Bijela rijeka river spring, SBR = Bijela rijeka river upper reaches, ICR = Crna rijeka river spring, SCR = Crna rijeka river middle reaches, CM = Crna rijeka river lower reaches, KR = Korana river, PP = Plitvica stream, KM = Tufa barrier Kozjak-Milanovac, LB = Tufa barrier Labudovac, NOB = Tufa barrier Novakovića Brod. Environmental factors (green arrow symbols): T max = maximum water temperature (°C); O2 = O₂ (mg L⁻¹); pH = pH value; Con = Conductivity (µS cm⁻¹); Al = Alkalinity (mg L⁻¹ CaCO₃); Vel = Water velocity (cms−1); Dep = Water depth (cm); NO3 = Nitrates (mg L⁻¹); NH4 = Ammonium (mg L⁻¹). Taxa (red triangle symbols): A = juvenile Baetidae, B = Alainites muticus, C = juvenile Baetis sp., D = Baetis cf. nubecularis, E = Baetis rhodani, F = Centroptilum luteolum, G = Procloeon pennulatum, H = juvenile Caenis sp., I = Caenis horaria, J = juvenile Ephemerellidae, K = Serratella ignita, L = Torleya major, M = Ephemera danica, N = juvenile Heptageniidae, O = Ecdyonurus submontanus, P = Rhithrogena braaschi, R = juvenile Leptophlebiidae, S = Habrophlebia lauta, T = Paraleptophlebia submarginata, U = Siphlonurus croaticus.