Functioning of Ecotone Systems at the Tsimlyansk Reservoir Shores

摘要

The paper describes changes in environmental factors (reservoir water level, depths of groundwaters and their mineralization) of the "water-terrestrial" ecotone system and the ecosystem components (soils and vegetation) at various types of Tsimlyanskreservoir coastal areas. The study is based on field monitoring surveys conducted from 2004-2013. It was revealed that maximal levels of the reservoir water exhibit trended toward a decrease, while the minimal and medium trended toward an increase. The amplitude of the water level fluctuations over the last few years seldom exceeded 2 m and showed a tendency to decrease. The aforementioned dynamics facilitate continuation of the abrasion processes and a decrease in the areas of short-term flooded territories outside the coastline. This endangers the belt forest formed at the shores at the height of 35.5 m above the sea level. No statistically significant dependence of the groundwater level on atmospheric precipitation was revealed, but the resevoir level of the did not expand past the coastline over the last few years, with below-average annual precipitation values. Multiannual and seasonal fluctuations in the depths of groundwaters relate to the reservoir water level. Areas situated at a distance ofnot more than 200 m from the coastline are subject to flooding. In total, 157 species of vascular plants (11 species are trees and shrubs) were recorded at the reservoir shore area. Maximal species richness (110 species) was found at shore areas subjectto short-term flooding (the dynamic block). Maximal values of primary production were registered in the amphibial block, within the belt of reed marshes.