Habitat diversity of grassland coommunities in Central Podillya and their sozological estimation

Rare grassland habitat classification scheme is given based on EUNIS system. The IV-V level in the scheme is corresponded to the alliance level of floristic classification, the VI level is corresponded to the associations, subassociations and variants. The comparative characteristic of rare grassland habitats and syntaxons is given in the paper. Selection of syntaxons is held by JUICE, TWINSPAN Modified, PC-Ord Software. The interpretation of syntaxons is performed using Ukrainian and foreign scientific papers. Sozological estimation is considered on different factors as antropogenic transformation, recoverability, position in the succession row, regional representative, distribution, ecological amplitude, ecological conditions, the presence of invasion species, hemerobic degree, the ratio between the types of strategies, sozological significance, synphytosozological status. Habitat classification scheme until sixth-seventh level has been built. This scheme counts 25 units of VI level, 15 units of V level, 10 units of VI level. Rare extent of Central Podillya grasslands has been estimated. It has been determined that rare habitats protected by Habitat Directive 92/43/EEC and Bern Convention are sporadically spread in the Bug and Dnister rives valley. It has been given comparative characteristic of rare habitats and synthaxonomical units. It has been determined that. rare grasslands of Central Podillya are communities of Festuco-Brometea class, Fetucion valesiacae alliance, Cirsio-Brachypodion pinnati alliance, Bromo-Festucion pallentis alliance, Artemisio marschalliani-Elytrigion intermediate alliance; Molinio-Arrhenatheretea class, Calthion alliance, Cynosurion cristati alliance, Alopecurion alliance; Koelerio-Corynephoretea class, Sedo albi-Veronicion dillenii alliance. Rare steppe grassland habitats are assessed as very rare habitats in Central Podillia ( Sesleria heufleriana, Stipa pulcherrima, S. pennata, Poa versicolor-dominated communities). Ecological assessment is conducted at the level of alliances. The leading factors of ecological differentiation of rare grassland habitats are humidity, carbonate content, aeration, and acidity. These factors correlated at the level of 0,6-0,7 and promote distribution of rare grassland habitats in Central Podillia.