Successional development of shrub-woody vegetation on natural river banks along certain watercourses in the Julian Alps and their foothills (western Slovenia and northeastern Italy)

We conducted a phytosociological survey of pioneer shrub and shrub-wood (brushwood) communities on river banks at the contact of gravel bars and rockfall, slope debris or colluvium in the spring area of the Nadiža River, in the gorge of the Soča River between Srpenica and Kobarid (Log Čezsoški and Magozd), in the Tolminka valley, and in certain other locations in the hills of western Slovenia. We identified a successional sequence of two grey willow and hop hornbeam communities, which we classify into the associations Salicetum eleagno-appendiculatae (Salicion eleagno-daphnoidis) and Peucedano verticillari-Ostryetum carpinifoliae (Fraxino orni-Ostryion). Both are indicators of natural river banks that have not been artificially stabilized. We expanded the knowledge of hop hornbeam communities in the pre-Alpine–northern-Dinaric part of Slovenia with a description of a new association Scopolio carniolicae-Ostryetum carpinifoliae. Its sites are characterised by slightly moist soil, and its stands by a higher proportion of species of the alliance Tilio-Acerion.