Risposta della vegetazione e dell'artropofauna alla tempesta Vaia nella Regione Veneto

The disturbance risks in forest ecosystems are increasing due to extreme weather events related to climate change. How forest dynamics will respond to extreme disturbance activities in a short time window remains uncertain. Plant communities present in the post-disturbance phase have a sensitive response to the new micro-climatic conditions, which can alter the normal path of forest recovery. In particular, species diversity of the sites affected by disturbances can be widely different from non-affected areas. A new configuration of forest ecosystems could also determine drastic changes in arthropods’ ecological niches. The aim of the thesis is to describe and understand ongoing changes in forest ecosystems in a changing climatic world, in order to contribute to future forest management approaches. The study was carried out in the Alpine areas of the Veneto region, in northern Italy. The 2018 Vaia storm has been recognized as the most damaging windthrow event ever recorded in Italy. The Veneto region was one of the most affected regions, with 2.2 million m3 of fallen wood. The sampling included 35 windthrow gaps, divided into four macro-areas, where data about plant communities established in the post-disturbance phase was collected. With the purpose to assess the impacts of the disturbance event, six control-sites were chosen in neighbouring areas unaffected by the storm’s disturbance. In the same sampling areas, information about natural forest renewal and abundance within certain indicator-insect families and orders was also collected (Carabidae, Staphylinidae, Opiliones and Araneae). A total of 333 species of vascular plants were identified, 310 of which were sampled in windthrow sites. A total of 13.089 insects were identified, significantly higher in the windthrow sites than in control sites, showing an increase in biodiversity after the storm. The sampled sites differed in significant environmental and topographical variables (e.g., windthrow gap percentage, the elevation-aspect interaction, and the slope), explaining the composition of the plant and arthropod communities. The monitoring of plant and insect biodiversity during post-disturbance phases can contribute to critical research points related to climate change, such as the loss of biodiversity in forest and related loss of ecosystem services.