Macrozoobenthos of water objects affected by the South-Ukrainian electric power-producing complex

Changes in structural characteristics of macrozoobenthos of water objects affected by the South-Ukrainian Electric Power-Producing Complex regarding large-scale hydrotechnical construction are analyzed. The performed research of macrozobenthos showed that human activities significantly changed natural development of the hydrobiocenoses of the Southern Bug R. and, as a consequence, the Bug Estuary. The intensified human impact and eutrophication led to unification of the fauna in the lower reaches of the river, which resulted in disappearance and replacement of specific Ponto-Caspian species of hydrobionts with species of wide distribution and resistant to pollution. Changes in the hydrological regime and anthropogenic pollution led to disappearance of a number of species, primarily of endemic and relic ones, due to which the Dnieper-Bug interfluve had its own individual features. With the ecological niche previously occupied by these species being free now, other species, often quite aggressive invaders, occupy these biotopes. This is facilitated by creation of water objects with specific conditions such as the year-round thermal regime close to subtropical one, which promotes reproduction and successful acclimatization of alien species. The research results can be used to forecast possible changes in the ecosystems of some water bodies and to assess their ecological status.