Spatial distribution of Gmelinoides fasciatus Steb. in Thermally Polluted Water (Belovo Reservoir, Southwest Siberia)

Gmelinoides fasciatus (Stebbing, 1899) is a Baikal endemic amphipod that has recently become widespread in Eurasia. This species accidentally entered the cooling reservoir of the Belovo power plant and became successfully naturalised there. This study describes the peculiarities of G. fasciatus distribution in reservoir sites with different thermal regimes and analyses the environmental factors that limit its spread. The use of heating areas for prevernal breeding promoted the rapid expansion of G. fasciatus in the cooling reservoir. Silted soils, depths greater than 1 m and water heating above 26°C limit the dissemination of G. fasciatus in the reservoir. Invasion of G. fasciatus in the Belovo reservoir has not caused the extinction of the indigenous species Gammarus lacustris. The structural characteristics of aboriginal communities at unpopulated and populated by G. fasciatus zone of reservoir were not statistically different. Invasion of G. fasciatus did not aggravate the competitive interactions in the benthic communities.