Examples of the sampling sites in Croatia: Pannonian Ecoregion: A–Petrinjčica River (Miočinovići), B–Trepča River (Trepča), C–Kravarščica River (Dabići); Dinaric Ecoregion; Continental Subecoregion: D–Curak River (at confluence with the Kupa), E–Kupa River (Kupari), F–Korana River (Veljun); Dinaric Ecoregion; Mediterranean Subecoregion: G–Krka River (Marasovine), H–Zrmanja River (Butiga), I–Kobilica River (Kusac).