Spatial distribution of rotifers (Rotifera) in monospecies beds of invasive Vallisneria spiralis L. in heated lakes

Species abundance and richness of rotifer communities occupying monospecies beds of Vallisneria was studied in Lake Licheńskie included in the open cooling system of heat and power stations. Differences were found in rotifer numbers, species composition and diversity between sampling points within the same location and between the locations. Factors that seem to be responsible for the high diversity of rotifer communities inhabiting Vallisneria beds are: large-scale horizontal diversity (between macrophyte patches), small-scale horizontal diversity (within patches) and the high vulnerability of Vallisneria epiphyton to disturbances caused by wave action.