CHANGES IN STRUCTURE AND BIODIVERSITY OF SOIL FAUNA ON FOREST-STEPPE CATENA IN CENTRAL RUSSIA

For the first time, studies on the influence of mesorelief on soil fau na structure and biodiversity in a forest-steppe zone of the Central R ussia were performed. The soil mesofauna of eight forest plots located on the watershed slope was studied. Changes in the content of dominan ts, trophic structure, fauna abundance, and parameters of invertebrate biodiversity were analyzed for various mesorelief components. Biodive rsity and likeness indices were shown to be minimal for undisturbed ha bitats at the extreme positions of the catena studied (watershed and o verfloodland slope parts). Fauna structure was found to correspond to the local dynamics soil processes. At the transitive position, formali zed parameters displayed the highest values. In the mesopedobiontic co mplexes of the middle part of the watershed slope, faunogenetic elemen ts characteristic of the entire landscape zone were significant: repre sentatives of a group of forest-steppe species occurring only in the z onal habitats within the boundaries of the forest-steppe were included in the content of dominants. The groups of invertebrates of secondary forests and forest plantations at the upper and lower positions of th e catena displayed high similarity indices to the fauna of the middle part of the catena. These areas can be seen as the channels of soil fa una distribution over the mesorelief profile. The results obtained dem onstrate the significance of mesorelief as a factor determining specif ic distribution and structure of the soil fauna on the plain.