Keywords
drainage system, Upper Sava River Valley, Croatia, traditional methods of channel maintenance, rare plants, endangered plants, vulnerable plants, neophytes, Riccia fluitans L., Marsilea quadrifolia L., Utricularia vulgaris L., Sagittaria sagittifolia L., Eleocharis acicularis L., Leersia oryzoides (L.) Swartz, Wolffia arrhiza (L.) Hork ex Wimm., Solidago gigantea Aiton, Helianthus tuberosus L., Amorpha fruticosa L., Echinocystis lobata (Michx) Torr. et Gray, Panicum dichotomiflorum Michx.