Potential impact of climate change on the spatial distribution of key forest tree species in Italy under RCP4.5 for 2050s

Abstract Background: Forests provide a range of ecosystem services essential for the human wellbeing and their ability is influenced by climate background and further connected to forest management strategies. Italy is a well-known biodiversity hotspot but an uncertainty assessment of the potential impact of climate change is still missing in this country. The aim of this paper is model the potential impact of climate change on 19 tree species occurring across the Italian forests using a species distribution modelling approach, six different Global Circulation Models (GCMs) and one Regional Climate Models (RCMs) for 2050s under an intermediate forcing scenario (RCP 4.5). Results: While no sensible variation in the spatial distribution of the total forested area has been predicted with some tree species gaining space and covering the spatial contractions of others, results showed substantial differences between each species and different climate models. The analyses reported an unchanged amount of total land suitability to forest growth in mountain areas while smaller values were predicted for valleys and floodplains than high-elevation areas. Pure woods were predicted as the most influenced when compared with mixed stands which are characterized by a greater species richness and therefore a supposed higher level of biodiversity and resilience to climate change threatens. Pure softwood stands (e.g. Pinus, Abies) were more sensitive than hardwoods (e.g. Fagus, Quercus), probably due to their artificial origin which established pure stands with tree species generally more prone to admixture with others in (semi)-natural ecosystems.Conclusions: Forest management could play a fundamental role to reduce the potential impact of climate change on forest ecosystems. Silvicultural practices should be aimed at increasing the species richness and favouring hardwoods currently growing as dominating species under conifers canopy, stimulating the natural regeneration, gene flow and supporting (spatial) migration processes.