Diversity of beetle species and functional traits along gradients of deadwood suggests weak environmental filtering

Gradients in local environmental characteristics may favour the abundance of species with particular traits, while other decline, or different traits at same time, without an increase average abundances. Therefore, we asked: do variations and differ along gradients deadwood variables? Do trait occurrence change richness within between functional groups? Thus, analysed beetle assemblages five forest sites located Italy, Apennines mountains. From 2012 to 2018 sampled beetles types 193 plots characterise gradient: standing dead trees, snags, downed coarse woody debris, stumps. We modelled relative abundances trophic occurrences against variables using joint distribution models. Out 462 species, only 77 showed significant responses least one type, a weak mean response across species. Trophic groups mostly negative variables. Species increased among for phytophagous saproxylophagous. Trait did not sites, except However, changed significantly several some sites. found that increases result decreases given group, but rather null positive relationships were suggesting low interspecific competition. Our findings suggest Mediterranean mountain forests there is still room increasing level naturalness, what concerns management. On side, our competition substrates low, on side they indicate volume improve overall also