ECOLOGICAL AND COENOTIC ASPECTS OF THE STEPPE PHYTOCOENOSIS FORMATION

Abstract

The article presents the materials on the study of the ecological conditions
of the development of steppe communities in the Stavropol Territory. Geobotanical descriptions of phytocoenosis served as the basis for the study of plant associations. In order to assess steppe phytocoenosis and ecological conditions of their development, L.G. Ramensky's
ecological scales were used. The aim of the study was to identify the environmental conditions of the habitat of natural communities within which wild flora species passed through the
stages of their life cycle, including the environmental factors, which affected them. It was discovered that the vegetation cover of steppe communities was not identic and they were in different ecological environments. Depending on the irrigation adequacy, steppe ecosystems are
divided into xeromesophytic (30-57 %) and mesoxerophytic (18-41 %), according to the predominant species. Natural communities were located at different hypsometric levels (from 9
to 13) and were not identical in terms of the degree of hydromorphism of different types. The
characteristics of the soil cover were quite stable and equaled to 14 points on scales of richness and salinity of soils. In other words, the species of wild flora were provided with nutrients so much that it was enough for plant species to pass a full life cycle in the phytocoenosis.
The impact of economic activity on the vegetation cover of natural communities, which were
used as hayfields or pastures was different – from a weak influence of grazing (2-4 points) to
moderate (5 points) and strong (6 points). The vegetation of phytocoenosis was similar in
species composition to virgin land (units 1, 8, 9, 12) or was subjected to deterioration effects
of varying intensity (units 2-7, 10, 11). Against the background of natural and human impacts
on plant associations, the primary factor of degradation of vegetation cover was intensive, unregulated grazing of animals.