DYNAMICS OF SPECIES OF MEADOW COMMUNITIES RICHNESS UNDER THE INFLUENCE OF UNSTABLE CASPIAN SEA LEVEL

Abstract

Based on the analysis of phytocenotic indicators, the results of the study of the state of the meadow community of the Caspian lowland are presented. The coastal plains of the Caspian region are the youngest land areas, the vegetation cover of which has not yet formed and is at different stages of successional development. The flora and vegetation of the regions was significantly influenced by transgressive and regressive stages in the history of the Caspian Sea. Their coastline was constantly changing under the influence of natural, and now also anthropogenic factors. At the present stage, the Caspian Sea is in a transgressive phase, since 1978 the sea level has risen by 2 m. Long-term impact on meadow communities of natural and anthropogenic factors leads to significant changes in the indigenous communities of this region. The general trend in the dynamics of meadow vegetation in plain Dagestan has been associated in recent years with the processes of steppe formation, and in many cases - salinization and desertification. The coastal and deltaic phytocenoses of the young plain are formed not so much under the influence of zonal conditions, but more under the complex interaction of local conditions - the changing level regime of the Caspian Sea, groundwater, high summer temperatures, strong anthropogenic pressure (irregular grazing, wind erosion, secondary salinization), variegated lithological, soil and the associated complexity of the vegetation cover. Such changes in meadow and meadow-bog vegetation were first noted by E.V. Schiffers. The aim of the research was to study the state of the meadow community by assessing phytocenotic indicators: the structure of vegetation cover, projective cover, species diversity, abundance of species.