Regeneration Status and Diversity of Woody Plant Species in the Priority Habitat 91E0* in Nestos, Greece

The priority habitat 91E0*, consisting of alluvial forests with Alnus glutinosa (L.) Gaertn. and Fraxinus excelsior L., represents a vital ecosystem along Europe’s riverbanks and floodplains. In Greece, the alluvial forests of the Nestos Delta are particularly notable for their unique composition and ecological importance. The present study aimed to assess woody species’ regeneration status and diversity in the priority habitat 91E0* in Nestos, Greece. In the studied area, 13 plant species belonging to 12 genera from 10 families were recorded. The most numerous families were Salicaceae (23.07%) and Moraceae (15.38%). The regeneration index (IR) for Amorpha fruticosa L. and Acer negundo L. exhibited a substantial decline, decreasing from 31.75 and 21.12 cm m−2 to 2.07 and 2.6 cm m−2, respectively. This intervention created space for expanding native tree species such as Cornus sanguinea L., Morus alba L., and Populus alba L. The results demonstrate that the regeneration of P. alba L. is currently the most extensive (31.1%) in the alluvial forest, with C. sanguinea L., M. alba L., and A. glutinosa (L.) Gaertn. also showing significant regeneration. In contrast, the regeneration of F. angustifolia Vahl remains very limited (0.21 cm m−2), indicating the necessity for targeted restoration efforts.