FEATURES OF FODDER PASTURE PLANTS IN TERSKO-KUMSKAYA LOWLAND UNDER ANTHROPOGENIC PRESSURE

Abstract

Study of the regularities of changes in the resistance of defferent forage grasses to the main  common stress factors, ecological and biological characteristics of pasture forage grasses, their productivity under the influence of the changing grazing regime and indentification of changes in species composition of the vegetation cover. Geobotanical descriptions of vegetation were carried out according to Ramensky's method. The selection of plant groups according to the degree of pasture degradation was used using the criteria proposed by B.M. Mirkin (1985). Jaccar`s formula was applied on three key areas to determine the ratio of vegetation species composition generality. One of the areas is the least altered, the other two areas are depending on anthropogenic pressure. The vegetation communities of the Kochubey biosphere station are in a state of degradation, there are changes in the structure of phytocenoses, loss and disappearance of forage grasses. Seven main forage grasses from the Poaceae family, 2 species from Chenopodio?deae, and 3 species from Asteraceae that were not adapted to harsh environmental conditions fell out from the grass stand. Only the drought-resistant, dominant species have survived. A total of 45 species were recorded, out of 10 families from 3-10 dominant plants in three plots, depending on the anthropogenic pressure. The most sensitive to external factors are the following plant species: Agropyron desertorum, Bromus squarrosus, Br?mus horde?ceus, Poa bulbosa, Eremopyrum orientale, Phleum pratense, Eragrostis minor, Atropis gigantea, Suaeda microphylla, Petrosimonia brachiata, Artemisia salsoloides. In the structure of phytocenoses, semi-shrubs - halo xerophytes with a high productivity of 11.5-11.7 centners / ha prevail. The coefficient of the floristic community of species according to Jaccar for plots 1 and 2 is 14.8% compared to the third plot - 7.1%, which indicates the increased impact of all external environmental factors, mainly anthropogenic pressure. The vegetation communities of the Kochubey biosphere station is in a state of thinning of the grass stand in the places of the greatest anthropogenic pressure with the possible restoration of forage grasses under certain normalized pressure.