Diverzita vodních měkkýšů řeky Turiec (Slovensko) [Diversity of aquatic molluscs of the river Turiec (Slovakia)]

Abstract

During a detailed faunistic survey of the river Turiec in northern Slovakia in 2013–2022, we found 18 species of aquatic molluscs (8 gastropods and 10 bivalves) at 9 sites. The most species-rich assemblages were in the middle course of this river. The surprisingly low species richness in the lower course could be due to the heavily altered riverbed and polluted water. The most frequently recorded species were the gastropods Ancylus fluviatilis and Radix ampla and the bivalves Pisidium casertanum and P. subtruncatum. The rare and critically endangered bivalve Pisidium tenuilineatum was recorded in 2017 at one site, and two endangered species, Unio crassus and P. amnicum, were found in rich populations in 2022. The presence of these species confirms the relatively good preservation of the middle course of Turiec. The non-native species Physa acuta was found in this river for the first time.