Saproxylic beetle communities in beech forests with differing degrees of naturalness in the Abruzzo, Lazio and Molise National Park (Central Italy): a preliminary study

Saproxylic beetles are among the most ecologically important insect guilds in forest ecosystems, contributing to wood decomposition and nutrient cycling, and are widely used as bioindicators of forest naturalness and stand structure. The Abruzzo, Lazio and Molise National Park (PNALM), in the central Apennines, harbours some of the oldest and best-preserved beech (Fagus sylvatica L.) forests in Europe, including UNESCO World Heritage old-growth stands alongside managed high-forests. Despite their relevance, data on the saproxylic beetle fauna of these forests remain limited. This study provides a preliminary characterisation of the saproxylic beetle community in beech-dominated ecosystems of the PNALM, comparing stands with different naturalness in terms of family composition, alpha and beta diversity.

Twenty-four ethanol-baited cross-vane traps (3 per site) were deployed in a triangular pattern across 8 sites (4 old-growth and 4 managed beech high-forests) and inspected monthly for sample collection and lure replacement. Given the large number of specimens collected (8,878 individuals), identification was carried out at family level to provide a first overview of community structure. Families with recognised saproxylic habits (e.g. Cerambycidae, Elateridae, Eucnemidae, Lucanidae, Ptinidae) were retained as the saproxylic subset to compare assemblages between sites and management types.

Of 43 beetle families recorded, 24 were saproxylic, accounting for 95% of all sampled individuals. The distribution was strongly unbalanced: over 80% of saproxylic individuals belonged to only three families (Curculionidae, Salpingidae and Cryptophagidae). Alpha diversity showed no marked differences between managed and old-growth stands. Community composition was structured primarily by site (PERMANOVA, R² = 0.35, p < 0.001), whereas management had no detectable effect (p = 0.38).

These preliminary results indicate that among-site heterogeneity, rather than management regime, is the main correlate of saproxylic beetle community variation in PNALM beech forests. As family-level data may mask species-specific responses, longer-term monitoring and species-level identification are needed to clarify the role of forest management in shaping saproxylic beetle diversity.