Assessment of ecological state of Rostov zoo soil

A comparative study of ecological and biological parameters of soils of the Rostov-on-Don Zoo was carried out in 2017-2020. Monitoring sites were studied in areas of various purpose: aviaries with different animals, recreation area, park area. The control plot was a relatively undisturbed park section in the territory of the zoo. Different sites revealed heterogeneity of ecological conditions and soil properties. The most significant difference was in the physical properties of soils. Density, penetration resistance, and soil structure were degraded in aviaries with large animals: rhinos, zebras, deer. Using methods of bioindication, the degree of change in the soil of aviaries was determined compared with the soil of the control plot. The abundance of nitrogen-fixing bacteria of the Azotobacter genus was reduced in the soils of aviaries with zebras, rams, rhinos and giraffe due to the artificial addition of sand to the soil for the purpose of improvement of its physical properties. The activity of soil enzymes (urease and dehydrogenases) was significantly increased in the soils of aviaries due to their contamination with animal excretory products. A particularly high increase was in urease (up to 7.4 times relative to the control soil). The main problems of the topsoil of the zoo are overconsolidation, structural degradation, organic pollution, change in biological activity. The degree of change depends on the size of aviaries, the size and activity of animals and soil amelioration aimed at regulating physical properties of the soil.