Urban-ization as a factor of anthropogenic transformation of the nature in the valley of the small river Zelenka

Natural complexes of river valleys are an important part of the ecological framework of large cities. Ecosystems of the Zelenka river valley (Perm) provide ecological balance of a significant part of the catchment area of the Egoshikha river and the Egoshikhinskaya valley protected area located within it. In order to develop measures for the ecological rehabilitation of the Zelenka River valley area, a field survey was conducted. Based on field survey data the functional zones were recommended. The soil cover of the valley is composed of alluvial humus gleyey urbanized, gray humus urbanized and lithostratified soils. The main types of vegetation are grass-herb meadows overgrown with ash-leaved maple; floodplain grass-herb meadow and grass-reed communities; tree-shrub community dominated by ash-leaved maple; herbaceous community of weedy-ruderal species. 128 species of higher vascular plants were recorded. Iris pseudacorus, listed in the Appendix to the Red List of the Perm region and Cicerbita uralensis endemic to the Urals were recorded. Twenty-four bird species were identified, which is 28% of the total species diversity of birds in the Egoshikha River valley and 8% of the bird diversity of the city Perm. It was found that at the source of the river water is more mineralized, and at further flow there is a dilution of water. Calcium and sulfate-ion exceedances of maximum allowable limit were noted. According to the degree of degradation ecosystems of the surveyed area are mainly referred to very strongly degraded. Floodplain ecosystems are the closest to their intact state. In the nature conservation zone, attention should be paid to preserving the population of Iris pseudacorus; environment improvement is not recommended. For the nature restoration zone it is recommended to fence the territory and take measures to regulate the number of ash-leaved maple. A list of trees and shrubs for planting instead of the removed maple specimens is proposed. In the transition zone from urban area to nature it is recommended to step terracing, creation of a walking zone, directed formation ecosystems with phytocenoses, which are close to natural zonal ones in their composition and tiering.