Fire-induced taxonomic and functional changes in saproxylic beetle communities in fire sensitive regions

It is often suggested that fire acts as an environmental filter that selects species and functional traits, and reduces trait variability within communities, affecting ecosystem function and underlying services. This may be particularly important in fire-sensitive ecosystems, such as the central European Alps, where fires are scarce. According to climate and land use change scenarios in Europe, fire risk will increase during the next decades, raising important questions about the maintenance of ecological and functional resilience in these regions. We used two families of saproxylic beetles (i.e. Cerambycidae and Buprestidae) as model group to test the combined effect of fire and altitude on species and trait composition in the central Alps of Switzerland. Trait response was based on weighted means and variation of 15 traits over the communities. Our results showed an overall positive effect of fire on taxonomic and functional diversity, while indicator species and community analyses revealed that the response to fire was also modulated by altitude. The positive effect of fire and the presence of large populations of pyrophilous species suggest co-evolution with fire and adaptation to disturbance in the Alps. Biodiversity in the central Alps might thus be more resilient to fire than expected. In the light of climatic and land use changes, forest management and species conservation in the central Alps have to consider fire one of the major disruptive factors that have shaped and will shape species composition and ecosystem services.