Elevational gradients have proven to be useful to examine key factors shaping species diversity patterns. Th is study examines the eff ects of elevation, area, geometric constraints, habitat type, environmental factors and land-use intensity on terrestrial gastropod diversity patterns in Val M ü stair, an alpine region infl uenced by diff erent types of agricultural land use in the eastern Alps, Switzerland. Gastropods were sampled using a standardized method in 180 sites spanning an elevational range from 1215 to 2770 m and covering 11 diff erent habitat types. A total of 11 102 specimens representing 70 species were recorded. Observed species richness, statistically estimated true richness (Chao) and geographically interpolated observed richness were used as measures of local species richness. Th e comparison of three alternative models (environmental, geometric constraints and gastropod abundance models) revealed that the environmental model explained most of the variation in all measures of local diversity. Th e best model combining the predictors of all three models showed that elevation, soil pH and habitat type aff ected all measures of local species richness. Similar analyses conducted at the level of 150-m elevational bands showed that elevation was again the best predictor of species richness, while the area of the elevational band did not have any infl uence. However, in one out of the two measures of band species richness, the best model indicated that geometric constraints may also contribute to the observed pattern. At both spatial scales, all measures of species richness decreased with increasing elevation. An analysis of species-specifi c life-history traits showed that adult shell size of land snails decreased with increasing elevation. Most species with large shells were confi ned to lower elevations. Th e results indicate that environmental factors might be most important in shaping the observed patterns.