Authors: Drag, Lukáš; Burner, Ryan;Stephan, Jörg;Birkemoe, Tone ;Potterf, Mária ;Snäll, Tord;Sverdrup-Thygeson, Anne;Müller, Jörg;

Global climate change is rapidly altering the complex 3D structure of forests, which is a major habitat determinant affecting local communities. However, little is known about how functionally diverse wood-living (saproxylic) beetles, involved in the recycling of wood, will be affected by this change. Here we combine ecological and morphological traits available for saproxylic beetles and airborne laser scanning (ALS) data in Bayesian trait-based joint species distribution models to study how traits drive the distributions of more than 230 species in temperate forests of Europe. We found that elevation (as a proxy for temperature and precipitation) and the proportion of conifers played important roles in species occurrences while variables related to habitat heterogeneity were less relevant. Further, we showed that local communities were shaped by environmental variation through their traits. As predicted, ecological traits shaped species’ responses to forest structure more than did morphological traits. Both models, however, revealed strong phylogenetic signal in species’ response to environmental characteristics. Our findings provide support that strong habitat filtering based on evolutionary adaptions is a central process shaping saproxylic beetle communities. Therefore, future changes in climate and the forest structure may influence ecosystem functions by altering community trait composition.