Peculiarities of the zooperiphyton succession in beaver ponds of a small river

The increase in the species diversity of the zooperiphyton and intensifying succession due to the increase of the abundance of chironomid larvae (stage I) was observed upstream along the small Latka River (a tributary of Rybinsk Reservoir) during the first year after the appearance of the beaver dam, when the depth increased and the flow velocity decreased. In the beaver pond, which was overgrown by yellow water-lily, the zoocenose succession depended greatly on the abundance of the vegetating and fading plants. During the vegetation period, at high abundance of the yellow water-lily, the species richness of the zoocenose decreased, and then it increased again the next year, when new vegetation was low, and the old plants were decomposing en masse. Directly downstream from one of the beaver dams, the mollusks affected negatively the seasonal succession of the zoocenoses under an instable water level and current regime, when they removed nearly all the fouling from the substrates.