This dataset supports the manuscript "Marine Animal Forests as functional engines: Biotic filtering overrides biogeographic variability in the Mediterranean" by Licciardi et al. The study assessed the engineering role of the red gorgonian Paramuricea clavata on coralligenous benthic assemblages across seven locations in the Western-Central Mediterranean (Italy), spanning a bathymetric gradient of 20-40 m depth and two sampling times (Summer T0 and Autumn T1, 2023). The dataset consists of three sheets: species_abundance: Percentage cover data from 1300 photographic sampling units (0.2 m² quadrats) for 47 benthic taxa/morpho-functional groups, collected inside and outside P. clavata forests. Each row represents one replicate, identified by a unique ID encoding Region, Time, Location, Site, Condition, and Depth. species_traits: Species-trait matrix assigning each taxon to its corresponding categorical trait. necrosis: P. clavata status data (Mean Injured Surface, %) recorded through video transects at fixed stations in Sardinia and Campania at T0 (Summer) and T1 (Autumn), used to track tissue necrosis progression over the warm season.