The vegetation of the cretaceous outcrops of Novhorod-Siverskyi Polesie loess “islands” (Ukraine) and the new locality of Gentiana cruciata L

Abstract

The vegetation of the cretaceous outcrops of Novhorod-Siverskyi Polesie loess “islands” is represented by the grassland.' communities of the Artemisietea vulgaris Lohmeyer et al. in Tx. ex von Rochowl951, Festuco-Brometea Br.-Bl. et Tx. ex Soo 1947 Trifolio-Geranietea sanguineiT. Muller 1962 classes and shrubby phytocoenoses of the Robinietea Jurko ex Hadac et Sofron 198C class. The structure and composition of the plant communities are influenced by the degree of anthropogenic influence (both in the past and present) on the ecosystems of cretaceous outcrops. The determining anthropogenic factors contributing to the formation o: She ruderal communities were chalk mining and gardening. The influence of erosive processes is manifested in the spatial delimitatior >f plant communities of various syntaxonomic belongings. The anthropogenic successional communities: semiruderal grasslands anc herblands of the immoral and subboreal zones of Europe (Convolvulo-Agropyretum repen tis Felfoldy (1942) 1943, Poo compressae-yussilaginetum farfarae R. Tx. 1931) and scrub communities of temperate Europe, represented by the Elytrigio repentis-Robinietun. Smetana 2002 phytocoenoses typical for Steppe zones, prevail. Semixerothermic communities were found on the steep slopes of the cretaceous outcrops (eastern and southwestern expositions) - early successional stages with a significant amount of the characteristic species of the Festuco-Brometea Br.-Dl. et Tx. ex Sod 1947 class. On the cretaceous outcrops of Novhorod-Siverskyi Polesie loess “islands'" the communities of Trifolion medii T. Muller 1962 (meso-subxerophvtic fringe phytocoenoses on nutrient-poor but base-rich soils at lower altitudes of temperate Western and Central Europe) is localized on the slopes of the eastern and southeastern parts of the expositions which do not undergo anthropogenic influence and are separated by erosion forms. Such conditions were favorable in the Trifolio medii-Aurimonietuni Th. Muller 1962 association community and represented by two compact groups of individuals (the area of 0.5 nr each) and individual plants. In order to preserve the habitat of this rare species, it is worth creating here a reserve.