Novitskiy R. Scale, direction and consequences of alien fish species invasions in the Dnieper reservoirs

The dissertation is devoted to the study of the ichthyocenosis structure of the Dnieper reservoirs and their subordinate system that change under influence of alien fish species invasions. We determinate the scale, direction and consequences of the modern invasive process in the reservoir ecosystems of Ukraine. It is proved that the invasion, naturalization and distribution of alien species in the Dnieper reservoirs are an overall ecological process. The main water basin delivering alien fish for the Dnieper reservoirs is the Black Sea, and so we call it fish donor. The reservoirs of the cascade in turn act as donors of the Ponto-Caspian fauna for the river Pripyat and the Upper Dnieper (Kyivske Reservoir), for the basin of the river Siverskiy Donets (Kamyanske Reservoir and the Dnepr-Donbass Canal). It is proved that the Dnepr-Donbass channel is a transit water way for the promotion of alien species from the Dnipro Basin to the basins of Seversky Donets and Don.For the first time an analysis of the relationship between native fish species and species-invaders was carried out for the cascade of the Dnieper reservoirs. It has been proved that alien species have an aggressive character of adaptation to the new living conditions and more significant trophic and biotopic potential comparing with native species. A system for monitoring the invasive process in Ukraine's water basins has been developed. It includes the analysis of the invasive process, assessment of the state of communities and populations of alien species, research of consequences ecosystem changes, assessment of environmental risks, prognosis of new invasions, creation of database for management of the aquatic biological resources protection and rational use.