ECOLOGICAL AND COENOTIC CHARACTERISTIC OF CAREX DIOICA L. (CYPERACEAE JUSS.) IN UKRAINE

The results of ecological and coenotical peculiarities of Carex dioica L. (Cyperaceae Juss.) in Ukraine are presented. It was found that the most typical ecotopes for this species are moderately flooded sedge-hipnum, sphagnous-sedge open or thin forest bogs, wetlands and floodplains, shores of lakes etc. The species belongs to ecological group of hemi-continentals, that defines its distribution both on the plain territory of Ukraine and in the highlands. As regards to main ecological factors (thermoregime, ombroregime and cryoregime) C. dioica is characterized by the stenotopic amplitude and belongs to the group of sub-microtherms, sub-ombrophytes and subcryophytes. Taking into consideration the edaphic characteristics of the habitats, the range of tolerance of C. dioica, compared to the climatic ones, is somewhat broader. It is mesotrophic species that can also occur on mesooligotrophic, oligomesotrophic and mesoeutrophic sites of bogs. This species is sub-heliophyte, therefore it is able to withstand a minor degree of shading determining its occurrence within forest habitat types. This sedge is hygrophyte, hemihydrocontrastophobe, growing on moist, slightly aerated, peat soils with pH=5,5-6,5, relatively poor on mineral nitrogen. C. dioica belongs to the group of hemi-carbonatophobes, but also it can be found within calciphilous communities. Based on the coenotic analysis, it was established that C. dioica belongs to the communities of 2 classes of vegetation (Scheuchzerio palustris-Caricetea nigrae Tüxen 1937, Oxycocco-Sphagnetea Br.-Bl. et Tüxen), 4 orders (Caricetalia davallianae Br.-Bl. 1949, Caricetalia nigrae Koch 1926 em. Br.-Bl. 1949, Scheuchzeritalia palustris Nordhagen 1936, Sphagnetalia magellanici Kästner et Flössner 1933), 6 unions (Caricion davallianae Klika 1934, Sphagno warnstorfii-Tomentypnion nitentis Dahl 1956, Caricion canescenti-nigrae Nordhagen 1937, SphagnoCaricion canescentis Passarge (1964) 1978, Caricion lasіocarpae Vanden Berghen in Lebrun et al. 1949, Sphagnion magellanici Kästner et Flössner 1933) and 7 associations (Valeriano dioicae-Caricetum davallianae (Kuhn 1937) Moravec in Moravec et Rybníčková 1964, Meniantho trifoliatae-Sphagnetum teretis Warén 1926, Caricetum nigrae Braun 1915, Sphagno recurvi-Caricetum rostratae Steffen 1931, Sphagno recurvi-Caricetum lasiocarpae Zólyomi 1931, Drepanoclado revolventis-Caricetum lasiocarpae (Koch 1926) Rybníček 1984, Sphagno-Pinetum sylvestris Kobendza 1930). Coenotic optimum of the species is observed within Drepanoclado revolventis-Caricetum lasiocarpae and Sphagno recurvi-Caricetum lasiocarpae associations. Weakening of C. dioica coenotic position is observed within forest-bog communities and under the influence of the successions, passing in different directions (eutrophycation of the communities, formation of meadow ecotopes etc.), induced by the changes of hydrological regime, causing futher full displacement of this species.