Floristic characterization of the dry grasslands of the class Festuco-Brometea Br.-Bl. et Tx. ex Klika et Hadac 1944 in the Adriatic Region

Owing to their specific richness and high percentages of endemics and/or rare species, the southern European dry grasslands of the hilly and montane belts are currently considered a habitat worthy of the highest safeguard and attention (Council Directive 92/43/EEC). The Italian xerophytic basiphilous grasslands ascribed to the alliances Artemisio albae-Saturejion montanae, Phleo ambigui-Bromion erecti nom. inval., Alyssion bertolonii, Festuco-Bromion (also in Provence) and Cytiso-Bromion erecti have been assigned to the order Artemisio albae-Brometalia erecti, together with the alliance Xerobromion (Germany, Switzerland, Belgium, England and most of France). In the western Balkan Peninsula and in the eastern part of Italy, rather similar grasslands have been included in the order Scorzonero-Chrysopogonetalia. The precise geographical and floristic boundaries between these two orders have never been dealt with conclusively, whereas a high number of studies at a regional scale have been carried out. In order to solve these issues we have gathered the phytosociological tables concerning the dry grasslands associations described for Peninsular Italy so far and which were originally included in these two orders. Futhremore we have added the phytosociological tables of the western Balkans associations and those coming from adjacent countries (France, Switzerland, Germany and Austria) and the whole data set matrix has been classified; Indicator Species Analysis was utilized as an objective criterion for pruning the dendrograms and identifying Indicator Species of each cluster. The results show that the dry grasslands of the study area are divided into three main clusters: (1) Scorzonero-Chrysopogonetalia, widespread in the western part of the Balkan Peninsula and in the north-east of Italy; (2) Artemisio-Brometalia, mostly distributed in the central Europe and northern of Italy; (3) Peninsular Italy s.s. dry grasslands.