Features of floristic structure and productivity of dry meadows of the Left-Bank Forest-Steppe of Ukraine

Abstract

The article presents the results of study of floristic structure and productivity of the dry meadows preserved in the ravine and gully system in the Zmiiv District of the Kharkiv Region. The research was carried out at the model sites with floral composition and features of use typical for the Left-Bank Forest-Steppe of Ukraine. It was established that the total phytocenosis productivity depends on the phytomass fluctuations of two main groups of plants, forbs and grasses. The flora of the studied meadows includes at least 87 vascular plant species. The ten main families altogether number 70 species (80.5 % of the species composition). The families Asteraceae Bercht. & J. Presl (23 species, 26.4 %), Fabaceae Lindl. (11 species, 12.6 %) and Poaceae Barnhart (8 species, 9.2 %) are presented best. This ratio of families is characteristic of herbaceous phytocenoses of the Holarctic floristic realm. The Poaceae family plays the leading role in the formation of meadow phytocenoses, since its members often dominate the main meadow formations. Analysis of the flora ecomorph spectrum revealed prevalence of a xerophilous group that includes meadow, meadow-steppe and steppe species. The obtained data indicate a rather significant xerophytization of the study area, which is typical for the growing conditions of the dry meadows located on the watersheds with atmospheric type of humidification only. Perennial herbaceous meadow-steppe and some ruderal species prevailed in the life form spectrum (77.0 %), which is characteristic of the meadow flora of the Kharkiv Region. Annual segetal weeds, introduced from neighboring fields, contribute significantly to the meadow flora (17.2 %), in particular, such adventive species as Ambrosia artemisifolia L., Amaranthus retroflexus L., and Cyclachaen axanthifolia (Nutt.) Fresen. The research of phytocenose productivity showed that the Poaceae proportion in the meadows with high productivity is usually about 35‒40 %. In the meadows with low productivity, it can exceed 50 % that is explained by the leading role of the family Poaceae in the formation of meadow phytocenoses under high xerophytization of the vegetation cover.