Primi risultati per una nuova regionalizzazione fitogeografica del territorio italiano

Biogeographical regionalization should not be confused with ecological cartography or landscape classification, as biogeographical classification should be based only on species distribution. Therefore, the optimal data set for a phytogeographical (floristic) classification of Italy would be a floristic atlas including all the vascular plants species of the country: grid cells should be treated as OGUs (Operational Geographic Unit) and elaborated through multivariate presence/absence analysis. However, such an atlas has never been realized in our country. Aim of the paper is to present a quantitative phytogeographical classification of Italy based on available data, i.e. the new check-list of the Italian vascular flora, the large amount of published local floras and information about the distribution of Potential Natural Vegetation (vegetation series). As the check-list shows the plant list of each of the 20 administrative regions of Italy, these can be treated as OGUs for a first, coarse-grain framework classification of the country. A more detailed and fine-grained analysis of Italy’s phytogeographical units can be made analyzing a wide set of local floras, chosen – among the many available – on the basis of their study area surface and ecological heterogeneity. We also present a detailed analysis regarding the chorological attributes of species exclusive of the Thyrrenic regions compared to the Adriatic ones. The complex of the analysis confirm the presence of a gradient north-south and a clear separation est-west along the Peninsula. Results confirm that the adopted method is a valuable approach and propose a new boundary for the Centre- European Region in Southern Italy.