Syntaxonomy and phytogeographical differentiation of the Fagus woods in the Southwest Balkan Peninsula

Up to now the syntaxonomy of the Fagus woods of the southern Balkans is far less known than that of beech communities in the northwestern part of the Balkan Peninsula and in central and western Europe. A set of 607 phytosociological releves from southeastern Serbia, the Former Yugoslav Republic of Macedonia, and northern and central Greece was subjected to numerical classification acid ordination. These results were used for a syntaxonomic revision of Fagus, Fagus-Abies and Fagus-Acer woodland communities of the southwestern Balkans. The Doronico columnae-Fagenion (seven associations from Serbia, the F.Y.R.O.M., and high altitudes in northern Greece) and the Doronico orientalis-Fagenion (four associations from northern and central Greece) were distinguished. The results of ordination by Canonical Variates Analysis (CVA) showed a very distinct phytogeographical pattern of differentiation between community types. The floristic composition of Fagus woods changes markedly along the north-south gradient. The share of Subbalkan, Balkan, Submediterranean and Mediterranean species increases significantly towards the south, while the Central-European, European, Euro-Siberian, Euro-Asiatic and Circumpolar species decrease in the same direction. The syntaxonomic differentiation of the Fagus woodlands and their classification into regional suballiances reflects this gradient. With the rise in altitude, the number of Balkan, Mediterranean, Submediterranean, European and Euro-Asiatic species declines.