Thermophilous grasslands of southeastern Europe

A large proportion of grasslands found in southeastern Europe are thermophilous in the sense that they grow in the low elevation zone and are dominated by the warm season perennial grasses Chrysopogon gryllus and Dichanthium ischaemum (=Bothriochloa ischaemum). In fact, they are transitional between the typical Mediterranean grasslands dominated by annual grasses and the temperate grasslands dominated by perennial cold season grasses. In this paper, their distribution as well as their phytosociological, ecological and economic aspects are reviewed and discussed. They are distributed in the Quercetalia pubescentis zone, mostly in the Ostryo-Carpinion orientalis subzone, in large openings and represent the last stage of grassland colonization after the destruction of forests. Phytosociologically, these grasslands are classified in many associations or plant communities (e.g. Chrysopogono-Caricetum humilis, Thymo urumovii–Chrysopogonetum) mainly of the Festucetalia valesiacae order (Festuco-Brometea class), but also in other orders and classes such as Helianthemetea guttati, depending on their floristic composition. They are very productive grasslands with high grazing value for livestock. Because of their high plant diversity and the threat of vegetation succession, these semi-natural grasslands are under protection status in several areas (e.g. “Ponto-Sarmatic steppes”, which are a priority habitat type under the EU Directive 92/43).