Molluscs of the Cesky, Les Mts. - III. Katerinska Kotlina and northern part of Cerchovsky Les (Western Bohemia)

Data about recent molluscan fauna in the central part of the Cesky Les Mts. - Katerinska Kotlina and the northern part of Cerchovsky Les (Western Bohemia), with additional data from the phytogeographic district of Tachovska Brazda and Plzenska Pahorkatina, are given. Altogether 84 species (73 species of Gastropoda - 14 aquatic and 59 terrestrial; 11 species of Bivalvia) were recorded at 50 selected localities. The terrestrial molluscan fauna is dominated by woodland communities with the presence of montane and submontane elements such as Boreo-Alpine species Clausilia cruciata, Discus ruderatus, Vertigo substriata, Vertigo alpestris, occurring in fragmentarily preserved deciduous forests surrounded by spruce plantations which are dominated for the whole area of the Cesky Les. The record of Atlantic species Oxychilus alliarius has a particular importance. The snail Semilimax kotulae, typical of montane elevations was not recorded while Discus ruderatus was found at many localities of 500 to 860 m above sea level, respectively Clausilia cruciata occurring at one locality of 520 m a.s.l. Elements of open grounds nearly absent consisting of the species Vallonia costata occurring only at the ruins of abandoned villages. Special comments are given on the species Oxychilus alliarius, Clausilia cruciata and Stagnicola fuscus.