Responses of ground and dung beetle assemblages to extreme events: the case of the windstorm “Vaia” in the Italian Alps

Extreme weather events like windstorms are becoming more common, impacting forest ecosystems and presenting significant challenges for both biodiversity and management practices. This study examines the short-term responses of carabid (Coleoptera: Carabidae) and dung beetle (Coleoptera: Scarabaeoidea) assemblages to the disturbance caused by Storm Vaia (2018) in an Alpine valley in Northern Italy. Using pitfall traps across four habitats – pasture, mixed spruce-beech forest, intact spruce forest, and windthrown spruce forest – we analyzed species richness, abundance, functional traits, and community composition. Carabids, which are particularly sensitive to vegetation structure, exhibited significant shifts in community composition and functional traits, presenting lower resilience in comparison with dung beetles. By contrast, dung beetle assemblages demonstrated remarkable resilience, with minimal changes across habitats. These differences may be interpreted in the framework of ecological successions. Indeed, the resilience of dung beetles is due to their dependence on ephemeral resource patches, the serial colonization of which is denoted as heterotrophic succession. In contrast, carabids depend on prey or seeds and specific microclimatic conditions available at the different serial stages of an autotrophic succession. From an application point of view, our results confirm the value of carabids as bioindicators of forest disturbance and their usefulness to inform sustainable forest management practices under changing climatic conditions.