MEADOW BIOGEOCENOSES IN THE SUBALPINE BELT OF THE KABARDINO-BALKARIA STATE HIGH-MOUNTAIN RESERVE (CENTRAL CAUCASUS)

The study describes the current ecological-biological state of the high-mountain meadow biogeocoenoses' components (soils, vegetation, earthworms), which were formed in the subalpine belt of the Cherek-Bezengi canyon in the Kabardino-Balkaria State High-Mountain Reserve. The vegetation has been represented mainly by subalpine meadows. In medium-grass meadow phytocoenoses, the proportion of mesophytes was 70%, xeromesophytes - 20%, mesoxerophytes - 10%. Synecological indices (Shannon Index, Simpson Index, Pielou Index, Hartley Index and integral index) indicated a high floristic and phytocenosis diversity of hay meadows and a lower diversity of phytocoenoses of disturbed areas. Lumbricidae were the best represented in the mesofauna. Six species (with dominance of Dendrobaena schmidti) have been found in a small site of the Cherek-Bezengi canyon. These species are adapted to the cold and humid climate of the high-mountain region of the Central Caucasus. Distribution of forest earthworm species in the subalpine belt and changes of their habitats indicated more comfortable temperature conditions of meadow ecosystems in comparison with forest ecosystems. It also demonstrates the role of thermal balance as the basic limiting factor forming biotic coenoses. Based on enzymatic activity parameters and humus content, we determined the levels and spatial variation of biological activity of mountain-meadow subalpine soils which have been formed under meadow phytocoenoses. We have shown the essential dominance of hydrolase activity (high and middle levels) in comparison with oxidoreductase activity (low and very low levels). This characterises the intensity and direction of biochemical processes in high-mountain soil. Under conditions of disturbed phytocoenoses, we have determined a decrease of both the total soil biological activity (at 65%) and the integral biodiversity index (at 20%). A close joint connection between the investigated biological parameters (r = 0.74-0.86) reflected the important role of biotic communities' diversity in forming biological activity of mountain-meadow subalpine soils. The obtained data serve as a basis for monitoring of the soil-vegetation cover. Their protection is a requirement to maintain the biodiversity status in the Kabardino-Balkaria State High-Mountain Reserve.