Species restricted to the higher altitudes of low mountain ranges in Central Europe are among the species threatened. To quantify the influence of climate warming, we analysed the altitudinal distribution of mollusc species and modelled the occurrence and distribution of a high montane species under two scenarios of climate warming. Our analysis is based on samples of 3,437 individuals and 46 species collected at 111 localities. Number of individuals and species decreased with altitude. The slope of this decrease changed between 1,100 and 1,200 m a.s.l., which is the ecotone between mixed montane beech-fir-spruce and high-altitude spruce forests. In contrast to the majority of species and the number of species, the occurrence of Semilimax kotulae (Westerlund 1883), a Central European endemic, increased with altitude. Again, we found a change in the slope between 1,100 and 1,200 m a.s.l. Using geostatistical models of local temperature as well as spatial GLMs with Poisson and Gaussian errors, we modelled altitudinal distribution of diversity and species under consideration of environmental variables. Especially habitat age was an important predictor for the abundance of many species. For the high montane species S. kotulae, our model predicts a decrease in occurrence and abundance with global warming. Although global warming will lead to an overall increase in number of species, species occurring only at higher elevations, such as the S. kotulae, will probably become extinct within the study area.