Ecological-coenotic features of Thymus L. species (Lamiaceae) in flora of the western regions of Ukraine

Ecological-coenotic features of plant species resulted from their evolution and adaptation to environmental conditions determine the current species distribution patterns both globally and within localized areas. The paper presents the results of ecologi­cal-coenotic study of Thymus L. species in flora of the western regions of Ukraine. In course of the ecological analysis, it was revealed that in relation to major ecological factors, prevalent among the studied representatives are sub-mesophytes, hemi-hydrocontrastophiles, sub-acidophiles, semi-eutrophes, hemi-carbonatophiles, hemi-nitrophiles, sub-aerophiles, sub-microtherms, sub-ombrophytes, hemi-oceanists, hemi-cryophytes, and heliophytes. The decisive factors effecting thyme species distribution are climatic ones, especially climate humidity, in relation to which all the species appear stenotopic. In the western regions of Ukraine, the representatives of Thymus occur in communities of 13 classes, 19 orders, and 29 alliances. Most of species are assectators in the coenotic relation and mainly distributed in the meadow and steppe communities of Festuco-Brometea class. The widest coenotic amplitude features Th. pulegioides, Th. alpestris, and Th. pulcherrimus. The narrowest amplitude is characteristic to Th. moldavicus, which grows in communities of Festucion valesiacae union (Festuco-Brometea class) in the western regions of Ukraine