Structure and Diversity of Soil Zoocenoses in the Tunka Depression

Abstract

A landscape and ecological analysis is made of the structure of soil zoocenoses in the Tunka depression and the foothill area of Khamar–Daban. We examine the patterns of change in quantitative characteristics and taxonomic diversity of invertebrate communities in the landscape–ecological range under the influence of natural and anthropogenic factors. Taxonomic diversity and structure change mainly in the gradient of edapho–climatic and phytocenotic conditions which vary with the location of a biogeocenosis in the landscape. Within the taiga and forest landscapes, the general regularity of distribution of soil invertebrates is an increase in the number of species from steppificated pine and larch forests to dark coniferous–fir and mixed sufficiently moist biogeocenoses of the mountain forest belt. The relatively low heat availability of the root layer, combined with high humidity, and also the high temperatures that lead to drying of the soil, negatively affect on the taxonomic diversity of the mesopopulation. The main trend of change in taxonomic diversity of pedobiont communities is a decrease of the number of species in the gradient of increasing climate aridity, and an enhancement in hypothermaia and anthropogenic pressure. A structural and dynamical analysis identified two main types of structure of the communities: mesothermohygrophile (with a relatively small contribution from of insects and a large contribution from annelids), and xeroresistant (with a significant involvement of representatives of the insecta class. The first type includes zoocomplexes of taiga, forest, meadow and wetland biogeocenoses represented mainly by moisture–loving forms; the second type includes steppificated, steppe and radically anthropogenically disturbed biogeocenoses, the composition of which is dominated by invertebrates with relatively short development cycles and largely adapted to moisture deficit.