Tree-related microhabitat diversity as a proxy for the conservation of beetle communities in managed forests of Fagus sylvatica

Integrating the conservation of biodiversity into silvicultural practices is one of the main challenges facing forest owners in the promotion of an emergent approach to sustainable forest management across European forests. The Mediterranean forests are among the richest biodiverse forest ecosystems due to their environmental heterogeneity, but climate change is threatening their integrity, with critical implications for the availability of ecosystem services. Forests managed for commercial purposes are under increasing pressure to provide timber while supporting biodiversity. This study aims to analyse the relationship between tree-related microhabitats (TreMs), which are structures occurring on living or standing dead trees that constitute an essential substrate for several living species, and beetles, an important indicator species group for forest biodiversity monitoring. Four generalized linear models were fitted to assess the influence of environmental factors, forest structure, and biodiversity-related parameters on the abundance and richness of beetles, mainly on saproxylic beetles. The study highlights significant associations between the abundance and richness of individual groups and types of TreMs and the Italian Red List of saproxylic species. Therefore, TreMs can serve as a tool to map, monitor, and enhance forest biodiversity in managed forests.