Assessment of the Impacts of Animals on the Ecological State of Soils

Animals have a significant impact on the territory where they live by the process of their lives. The studied objects are located in the zone of dry steppes, where climatic conditions limit the development of vegetation and contribute to changes in soil characteristics, which, in combination with the impact of animals, enhances the effect. The purpose of the work was to assess the impacts of animals on the ecological state of the soils of the enclosures of the Wildlife of the Steppe Association. In the course of the study, the main indicators of the ecological state of soils in enclosures with animals on the territory of the enclosures of the Wildlife of the Steppe Association in the arid regions of the Rostov region were determined. We explored enclosures of different sizes, with African ostriches (Struthio camelus), emu (Dromaius novaehollandiae), goats (Capra sp.), Przewalski’s horses (Equus ferus przevwalskii) and saigas (Saiga tatarica), and on the territory with semi-free grazing of ungulates, that is, horses (Equus caballus), camels (camelus bactrianus), buffaloes (Bubalus arnee), yaks (Bos mutus), and lamas (Lama ganicoe). The studied areas differed in the intensity of soil degradation. To assess the physical condition the moisture, temperature, density, and structure of the soil were determined; pH, the gross chemical composition of soils, humus content, and biological activity were also assessed, and plots were ranked according to the degree of pasture digression. In the course of the study, the enclosure with African ostriches had the maximum degree of degradation of ten, which is characterized by severe inhibition of vegetation and soil degradation. As well, the soil density in the enclosure with African ostriches was the highest, 1.49 g/cm³, and the percentage of structure was the smallest, 37%. These parameters had a close negative correlation with the pressure of the animals' hooves and paws on the ground (–0.9). The humidity level in the studied areas did not rise above 11%; despite this, the enzymatic activity of the soils no longer depended on hydrothermal conditions, but on the influence of excretions of animal waste products. In enclosures with ungulates, in particular in the enclosure with goats, the activities of catalase and urease were always higher than in other areas. A high content of humus, 10.3%, was also noted there, which is uncharacteristic for chestnut soils and confirms the influence of animal life on them. According to the research results, the lowest quality of the structure, humus, and biological activity, as well as increased soil density, occurred in the enclosure with the African ostrich. The data we obtained explain the decrease in the growth and development of vegetation in the area where animals kept in crowded conditions live.