AbstractQuestionHow does a management change from sheep grazing by traditional pastoral herding plus occasional mowing to free‐ranging grazing in temporarily fenced areas affect vegetation in dry and wet semi‐natural grassland communities?LocationKösterbeck Nature Reserve, NE Germany.MethodsWe analysed the change in floristic and functional diversity and composition based on a resurvey of a 23‐yr‐old phytosociological data set. At 10 yrs after the original survey, the grazing regime had changed as described above. Since the exact locations of plots of the original survey could not be reconstructed, we placed the resurvey plots stratified randomly within the respective community types. Functional composition in relation to the environment was analysed with the RLQ approach using community means of Ellenberg species indicator values as proxies for environmental conditions.ResultsAlthough the grazing regime changed in the same direction in the whole area, the wet and dry grasslands responded differently: when the changes are analysed for the whole data set, they are hidden behind the differences between vegetation types, and neither plant species α‐ and γ‐diversity, nor species composition changes are apparent. However, when analysed separately, diversity changes were negligible for the wet meadow communities, whereas both α‐ and γ‐diversity increased in the drier sites, leaving β‐diversity unchanged. Despite the minor changes in species diversity in the wet grassland, functional composition changed considerably towards graminoid species. In the dry communities, an increase in species richness was accompanied by an increase in functional richness, and a trend towards competitive strategist species.ConclusionEven minor changes in grazing regime can significantly affect grassland communities, while the effects may vary strongly between vegetation types and incoherently across different measures of change. This suggests that thorough analysis of vegetation developments after management changes should be carried out on different levels of data set integration and should include several measures of change.