Quantitative phytogeography of the Italian beech forests

This paper presents a numerical analysis of the distribution patterns in Europe and adjoining regions of 242 vascular plant species occurring in the Italian beech forests. The classification of a matrix of species and of 531 Operational Geographic Units (OGUs) led to recognition of 15 different phytogeographic elements (chorotypes). The joint distribution of the species belonging to each chorotype is shown by a chorogram, which is a geographic map obtained by computer processing of the distributional data. Some of the chorograms show the main distributional centers for the beechwood flora in southern Europe: northwestern Balkan Peninsula and eastern Alps, southern Balkan Peninsula, Maritime Alps, northern Apennines, southern Apennines. Only 20% of the species are limited to narrow areas in southern Europe, and were not able to expand considerably their ranges in postglacial times. Migration from the refugia and colonization of vast areas in central and northern Europe led to intensive speciation phenomena, occurring chiefly through the formation of neopolyploid species. Several south European, narrow-ranging species, can be considered as palaeopolyploids with relict character. There is a good relationship between distribution and ecology of the chorotypes.