Variabilità naturale delle comunità macrobentoniche in un'area costiera destinata a ripopolamento di ostriche e sabellaria

This study investigates the spatial structure of the benthic macrofaunal community in the coastal area north of the Bevano River mouth (northern Adriatic Sea), within the framework of the LIFE NatuReef project, which aims to create a reef based on European flat oysters (Ostrea edulis) and Ross worms (Sabellaria spinulosa) polychaetes in this site. Benthic assemblages were analyzed in 2024 and 2025 to assess species distribution patterns, diversity indices, and relationships with key abiotic drivers, including bathymetry, sediment granulometry, and content of organic matter. Species abundances were interpolated to produce spatial distribution maps, and Pearson correlation analyses were performed between biological and abiotic variables. For the analysis seven dominant species were chosen: Chamelea gallina, Lentidium mediterraneum, Owenia fusiformis, Magelona sp., Prionospio caspersi, Prionospio cirrifera, and Phoronis muelleri. Diversity was assessed using species richness (S) and Hill-based indices (N1, N10). Results indicate that bathymetry and sediment composition were the primary factors influencing species distribution. Interannual comparisons revealed marked variability for some species, suggesting differential sensitivity to environmental fluctuations, while other species and the diversity indices showed high spatial consistency. These findings provide a quantitative ecological baseline for evaluating future habitat changes associated with reef restoration actions and contribute to understanding benthic community dynamics in soft-bottom coastal systems under restoration scenarios.