Riparian Forests of Alnus Species Communities and Their Role in Sustainability in the Romanian Carpathians and Adjacent Regions

Alnus riparian communities are important for ecological stability. Data on Alnus species were gathered from herbaria and literature, revealing that 54.39% of the information refers to Alnus glutinosa , 39.42% to Alnus incana , and 6.18% to Alnus pubescens . This information highlights the widespread occurrence of A. glutinosa and A. incana , as described in distribution maps, contrasting with the more limited range of the hybrid A. pubescens . Principal component analysis (PCA), utilizing standardized factors, was carried out on 217 relevés of the communities of the studied species. In these relevés, we identified a total of 169 plant species, categorized as herbaceous (83%), trees (11%), and shrubs (6%). Three distinct forest communities, Stellario nemorum-Alnetum glutinosae , Alnetum incanae , and Telekio speciosae-Alnetum incanae , emerged from relevé groups. The distribution maps of the three taxa were overlaid on maps of the region’s protected areas, revealing a substantial presence of these taxa within the protected zones. The research aims to highlight the sustainability and conservation importance of Alnus communities in the Romanian Carpathians, to contribute to ongoing conservation efforts and promote the viability and resilience of these ecologically important wetland habitats.