Vodní malakofauna dolního toku Lužnice se zaměřením na stav populace velevruba tupého (Unio crassus)

Abstract

This paper presents results of a malacological survey of the Lužnice River in ca 70 km long stretch between the inflow of its main tributary the Nežárka River in Veselí nad Lužnicí and its confluence with the Vltava River in Southern Bohemia (Czech Republic). Thirty-one species of aquatic molluscs (19 gastropods, 12 bivalves) representing 40% of freshwater molluscan fauna of the Czech Republic were found at 15 sites. Differences of molluscan assemblages upstream and downstream of Tábor town were probably caused by different characters of the watercourse. The occurrence of rare bivalve Pseudanodonta complanata was confirmed. On the other hand, two non-native species Physella acuta and Sinanodonta woodiana were recorded. The research was preferentially focused on the population of the endangered bivalve Unio crassus. Its occurrence was confirmed at 8 from 15 sites under study but altogether only 31 individuals were found. Less than four specimens were found at particular sites but one.

Keywords

• mollusca
• aquatic molluscs
• lužnice river
• faunistics
• unio crassus