Abstract
In total 47 rotifer taxa were found in the psammon of Włocławek Reservoir; 36 at the site in Dobiegniewo and 38 at Dobrzyń. Five species were classified as psammobionts, 14 as psammophiles, and the remaining ones as psammoxens. Psammobionts and psammophiles were observed mostly in the psammon at Dobiegniewo.
The highest density of psammon rotifers was noted in the euarenal zone of the flooded part of the reservoir. However, the highest density in the area near the swift current was noted in the hygroarenal zone. While the flooded part of the reservoir had four dominant species of rotifer: Lecane closterocerca, L. scutata, Lepadella patella and Cephalodella catellina, the area near the swift current had only two: Cephalodella catellina and Brachionus quadridentatus.
The most favorable conditions for the development of psammon rotifers was in the flooded area of the reservoir. In comparison with other dam-reservoirs in Poland, the community of these rotifer types in the Włocławek Reservoir was characterized by considerable species richness.