Distributional Patterns of Alien Species in the Open Shallow Areas of the Saratov Reservoir

摘要

The Ust of ahen species, their abundance, and distributional patterns are described for the macro-zoobenthic and nectobenthic communities of coastal areas of the Saratov Reservoir on the basis of studies conducted in 2006—2009. The disappearance of several native species is indicated.The Volga-Caspian transit route is one of the major ways of alien species exchange (Dgebuadze, 2003) As a result of flow regulation, the ecological conditions in the Volga River have changed greatly. The construction of reservoirs led to significant physical, geographical, hydrochemical, and biological changes in a former river environment. The riverine system was transformed into the reservoir ecosystem type. Currently, the species list has changed greatly owing to these activities and creation of a reservoir cascade, as well as owing to severe industrial pollution of some waterbodies (Zavyalov et al., 2007).