Classification, ecology and biodiversity of Central Balkan dry grasslands

Dry grasslands are highly diverse vegetation types of great importance for livestock production in rural Balkan areas. We analysed a large data set of phytosociological releves of dry grasslands (Festuco-Brometea and Festucetea vaginatae classes) in Serbia to produce the first overview of its classification, distribution, environmental conditions and biodiversity patterns. Phytocoenological releves from relevant literature sources and our own investigations were stored in the Vegetation Database of Serbia (EU-RS-002) and the Balkan Dry Grassland Database (EU-00-013). After heterogeneity-constrained random resampling, the final dataset contained 1,897 releves and 1,323 species. Species composition was classified hierarchically by the beta flexible method. We used species ecological indicator values for the estimation of the ecological conditions. Floristic and vegetation diversity and the conservation relevance of various dry grassland types, based on an assessment of endemic and protected species, were analysed. We identified 11 clusters, which were well characterised by their species composition and ecology. The first three clusters included loess and sand steppe grasslands mostly found in the Pannonian part of Serbia (Festucion rupicolae and Festucion vaginatae). The next three clusters consisted of Balkan ultramafic rocky grasslands of the order Halacsyetalia sendtneri, Balkan submediterranean mountain steppe grasslands on calcareous substrates, belonging to the order Astragalo-Potentilletalia and grasslands of the Balkan alliance Saturejion montanae on limestone. The third group of releves comprised Balkan alliances of dry grasslands on deep soils, the Chrysopogono-Danthonion and sub-continental steppes of the alliance Festucion valesiacae in hilly areas of Serbia, mostly in the thermophilous oak zone. According to ordination analysis (DCA), the main floristic gradient was largely determined by temperature and moisture. The Festuco-Brometea class exhibited high floristic diversity (1,323 plant species) and very high conservation relevance in view of the large number of Balkan endemic species (204). A total of 233 species and subspecies protected by national legislation within the studied vegetation were recorded.