Měkkýši Českého lesa – IV. Nové údaje pro jižní část Českého lesa

Data on recent molluscan fauna in the southern part of the Český Les Mts., with additional data from the phytogeographic district of the Plzeňská Pahorkatina hills, are presented. Altogether, 63 species (62 species of Gastropoda and 1 species of Bivalvia) were recorded at 22 selected sites. The author‘s collecting activity was focused on ruderal sites and abandoned villages along the state border. There is spruce plantation dominating in the woodlands with scarce malacofauna. The common forest species dominate there, with the presence of montane and submontane elements, such as Clausilia cruciata, Vertigo substriata, and Discus ruderatus, which occur in the rest of preserved deciduous forests. The record of Atlantic Oxychilus alliarius species is the fifth known in Czech Republic. The montane snail of Clausilia cruciata was found at one site at very low altitude of 550 m a.s.l. A slug species Arion alpinus, never found in this area before, was recorded at five sites. Its occurrence here is the westernmost one in the Czech Republic. The elements of open habitats presented by xerotherm sites and open wetlands were not recorded, except for the species Vallonia costata and Vallonia excentrica occurring only at the ruins of abandoned villages and their surroundings