A contribution to the phytosociological knowledge of the Molise region’s river ecosystems (central-southern Italy)

The hydrophilous and hygrophilous vegetation occurring within the Biferno and Sordo Rivers, in the Molise administrative region (central-southern Italy), was investigated according to the phytosociological approach and syntaxonomically classified. Twenty-three plant communities were identified belonging to the following classes: Salicetea purpureae , Alno glutinosae-Populetea , Phragmito-Magnocaricetea , Molinio-Arrhenatheretea , Epilobietea angustifolii , Bidentetea tripartitae , Filipendulo ulmariae-Convolvuletea sepium , Lemnetea minoris , and Potamogetonetea pectinati . A new association, the Zannichellietum peltatae ass. nov. was described as an ecologically vicariant community of the Zannichellietum palustris . From a nomenclatural point of view, the following association names: Bolboschoeno maritimi-Schoenoplectetum tabernaemontani , Persicario lapathifoliae-Xanthietum orientalis and Stuckenietum pectinatae were all proposed as nomina mutata nova (Art. 45 ICPN). Numerous discrepancies in the interpretation and syntaxonomic classification of the communities investigated were highlighted comparing the Prodrome of the Italian vegetation and the EuroVegChecklist. Finally, six habitats of conservation value according to the 92/43/CEE Directive Habitats were identified and a critical analysis on the correspondence between specific plant communities and related Annex I Habitat codes was advanced.