Dispersion graphics between hydrological stability (HS) and diatom indices: (a) IPS; (b) TI and (c) ICMi. Sampling approach patterns (T = filled diamonds; T + MH = filled squares) are also displayed. Different backgrounds graphically represent HS quality classes. Vertical lines graphically represent diatom indices quality thresholds (see Tab. 3). T = traditional approach; T + MH = experimental approach. M1 = Mediterranean macrotypology; small streams, mean altitude; M4 = Mediterranean macrotypology; mean dimension streams, mountain; M5 = Mediterranean macrotypology; intermittent streams.