Quantitative characteristics of soil mesofauna in the semidesert solonetzic complex of the north Caspian region

The results of long-term quantitative assessments of the invertebrate populations inhabiting the soils of a clayey semidesert are analyzed. The dominant species in the different soils of a solonetzic soil complex are compared. The distribution patterns of the dominant groups of invertebrates in relation to the soil and vegetation complexity dictated by the clearly expressed microrelief are discussed. The changes in the populations of the soil invertebrates are considered against the background of changes in the precipitation during the growing season in different years. It is shown that the population density of the soil invertebrates varies within broad limits in all the soils of the complex. At the same time, it remains considerably lower in the solonchakous solonetzes of the microhighs in comparison with that in the soils of the slopes and microlows. The most contrasting differences in the species composition and the numbers of soil invertebrates are observed for the solonetzes of the microhighs and the meadow-chestnut soils of the microlows. This work was performed at the Dzhanybek Research Station of the Institute of Forestry of the Russian Academy of Sciences on the Volga-Ural interfluve (30 km to the north of Lake El’ton).