Vodní měkkýši lomů ČSA a Vršany – počátek kolonizace Aquatic molluscs of the quarries ČSA and Vršany – the beginning of colonization

In 2022 and 2023, aquatic molluscs were surveyed in brown coal quarries ČSA and Vršany, northwestern Bohemia, where mining is ending and reclamation is in progress. Most water bodies were artificially created and relatively young, though some older habitats were present at the quarry edges. In the quarry ČSA, 20 species (17 gastropods, 3 bivalves) were recorded at 40 sites, while 13 species (10 gastropods, 3 bivalves) were found at 39 sites in Vršany. Molluscan communities were generally species-poor, particularly in deeper waters without shallows or with dense reed growth. Shallow, vegetated areas were more favorable. Physa acuta was the most frequent species. Three non-native species (Physa acuta, Potamopyrgus antipodarum, Ferrissia californica) were confirmed, and no protected or endangered species were found.