The resampling of 46 phytosociological plots 39 years later is used to characterize changes in the field layer of oak and oak-hornbeam forests in the South-East of the Czech Republic, where high densities of fallow deer, red deer and mouflon are kept in game preserves. Detrended correspondence analysis is used to demonstrate the general pattern of change. Changes in particular species performance, cover of field and shrub layers, diversity, life form spectrum and performance of zoochores are described. It is suggested that with increasing grazing pressure, native forest species retreat while the performance of species preferring soils rich in nitrogen and species of ruderal habitats increases. Simultaneously, mesic species are gradually replaced by xeric ones. Possible causes of these changes are discussed.