Use of soil biota in the assessment of the ecological potential of urban soils

Abstract

In assessing the ecological conditions and classification of urban soils, data about soil biota should be taken into account. The environment of urban territories is characterized by significant changes compared to their surrounding environments. It is established that the algal flora of urban soils lose their zonal features and features associated with the edification influence of higher plants. Specific biotopes with a definite species structure are formed in urboecosystems. Fifty 50 algae species have been recorded in the soils of the Henichesk urboecosystems (Kherson region, Ukraine): Cyanoprocaryota – 21, Chlorophyta – 13, Charophyta – 2, Eustigmatophyta – 1, Xanthophyta – 11, Bacillariophyta – 2. Among dominant and subdominant species were Cyanoprocaryota and Chlorophyta. The other phyla were represented by Klebsormidium dissectum, K. flaccidum, Hantzschia amphioxys, Eustigmatos magnus, Botrydiopsis eriensis. Compared with the surrounding environment, the urbanized flora of Henichesk has a low species richness, and is characterized by prevalence of Cyanoprocaryota and Chlorophyta species. The coefficient that takes into account the percentage of preservation of species richness in a particular urban area compared to the background indicators of species richness can be used to evaluate the urban transformation of soil biota. The degree of degradatory changes in the composition of living organisms and the direction of these changes depends on the specificity and intensity of exploitation of the territory of the urban ecosystem. The most diverse composition of algae species within the the city of Henichesk was noted in the recreational, residential, and transport zones, in comparison with the industrial zone and the zone of special use. Different functional areas of the city are distinguished not only by the algae species richness, but also by the composition of dominants. Among the dominants and subdominants of the recreational and transport zones were species of different phyla. The dominants and subdominants of the residential and industrial zones were Cyanoprocaryota species, in the zone of special use – representatives of Chlorophyta. The distribution of species richness of algae along the soil profile in the city acquires an atypical character. The species richness increases not in the most superficial layers of soil, but in the lower, aphotic parts of the soil profile. The soil biota, on the one hand, depends on the ecological conditions of soil, and on the other as a result of its life activity, changes the ecological functions of the soil, strengthening or weakening them. The reduction in the species richness of the soil algae of the urboecosystem Henichesk shows the limitations of ecological functions of urban soils. It is established that changes in the composition of algae in soils of urban ecosystems are one of the indicators of the presence and severity of transformation processes. These processes occur with the soil biota and soil as a whole under the conditions of urban ecosystems and can be used as indicators in the environmental assessment of urban soils, in the development and subsequent examination of ways to reduce negative expression of urbanization.