Distribution of the pulmonata mollusc <i>Lymnaea (Lymnaea) stagnalis</i> (Mollusca: Gastropoda) in the Samara River (The Saratov Reservoir basin)
The results of the study of L. (L.) stagnalis in the Samara River made it possible to establish the typical distribution of the species in different parts of the watercourse. The highest occurrence was recorded in the lower reaches of the river, which is due to the low speed of the current and the presence of thickets of higher aquatic vegetation. The mollusk prefers to settle in biotopes in thickets of Typha angustifolia L. and Potamogeton perfoliatus L. The maximum abundance was recorded in a small reservoir of the regulated section of the river, and the highest biomass values ?were noted in the backwater zone of the Saratov reservoir. The most significant environmental factors affecting the quantitative indicators of the mollusk in the Samara River are the water temperature, the area of ??overgrowth with macrophytes and the speed of the current.were noted in the backwater zone of the Saratov reservoir. The most significant environmental factors affecting the quantitative indicators of the mollusk in the Samara River are the water temperature, the area of overgrowth with macrophytes and the speed of the current.