MALACOFAUNA OF SVITYAZ AND PISOCHNE LAKES IN SHATSK NATIONAL NATURE PARK AND THE ROLE OF MOLLUSCS IN FORMATION OF CERCARIAL DERMATITIS NIDI

Abstract

The article presents the results of the research on the freshwater mollusc communities of Shatsk National Nature Park water bodies. Shatsky Lakes are located on the water­shed of water basins of the Baltic and the Black seas, that implies a wide diversity of species and a high level of dynamics of the hydrofauna status. The wetlands of the area, like the whole territory of Polissia, underwent a major transformation in the 1970s through the drainage reclamation. Subsequently, the Shatsk National Nature Park was unable to provide the effective management of the hydrological regime. Svityaz and Pisochne Lakes, used for the recreational purposes, were severely affected, as a result, the rate of their eutrophication increased. The climatic anomalies of recent years have contributed to further development of these changes. Eutrophication manifests itself in the overgrowth of the shoreline and shallows eventually leading to an increase in the density and diversity of water molluscs groups. Two classes of molluscs – the Gastropoda and the Bivalvia – represent the malacofauna of Schatsky Lakeland. Pulmonata subclass includes most freshwater molluscs, with domination of the gastropods. 22 species of molluscs were found during the study in the low-mesotrophic lakes of Svitiaz and Pisochne, 7 of which occurred only in one body of water, and 15 were common to both. Dreissena polymorpha is the dominating mollusc species in Svityaz Lake, and Lymnaea stagnalis – in Pisochne Lake. The molluscs of the invasive species – Potamopyrgus jenkinsi, whose ecological parameters have not been studied in the new location yet, can pose a threat to the indigenous species of molluscs and other organisms. Schistosomatidae larvae – furco cercarie that cause human cercarial dermatitis in Europe – were found in the molluscs under study. The representatives of Trichobilharzia and Bilcharziella genera are the most common pathogenic agents of the disease. Selective examination of individuals of nine species of molluscs (Lymnaea stagnalis, L. palustris, L. peregra, Planorbarius corneus, Planorbis planorbis, Anisus vortex, Viviparus viviparus, V. contectus, Bithynia tentaculata) revealed the invasions by the trematode partenits, including schistosomes.