Soil mesofauna of black alder forests of Kazakh upland in conditions of recreational and pasture digression

Abstract

The soil mesofauna of the black alder forests of Kazakh upland is studied as an indicator of the functional features of Alnus glutinosa plantings on the southeastern border of the area. Forests do not form massifs of a large area and are associated with the type of relief, valleys of streams and rivers, and the groundwater. Relict species of flora and fauna testify to the ancient origin and importance of black alder forests as refugia. The forest communities are changing under the influence of recreational load and grazing. It requires an early assessment of the state of terrestrial biocenoses. It has been established that black alder forests are characterized by high total biomass of mesofauna (from 13,6 g/m2 to 42,1 g/m2), where more than 85 % of the zoomass falls on the saprophilic complex. The density of the soil population is significant (from 272,6 copies/m2 to 503,55 copies/m2), i.e., in general, forests retain the features of zonal broad-leaved formations. Anthropogenic changes in the structure of pedobionts in black alder forests associations at different stages of recreational and pasture digression are revealed. There is a consistent decrease in the density index of the soil population (P = 145,6; 80,19; 69,7) and the proportion of forest species. A change of life forms in the model (Carabidae) and dominant (Lumbricidae) groups, an increase in the number of zoophages, a decrease in the total number and depletion of the species composition of saprophages are noted. The soil mesofauna reflects in its structure the biocenosis originality of relict black alder forests of the steppe zone and the continuity of biocenoses.