In the last several years, the grass Calamagrostis epigejos expanded into alluvial meadows in South Moravia. The aim of this study was to compare the changes of aboveground biomass production of intact meadow communities (Cnidion and Molinion alliances) and of degraded stands dominated by Calamagrostis epigejos, with respect to precipitation and soil moisture in studied sites. Substantial differences in aboveground yearly net production were found between both intact meadows (337-495 g.m -2 - Cnidion and 249-556 g.m -2 - Molinion) and stands dominated by Calamagrostis epigejos (571-838 g.m -2 and 462-887 g.m -2 respectively) in 1998-2000. Positive correlations were found between the cumulative precipitation in spring months and the aboveground yearly production in both intact meadows, whereas in Calamagrostis epigejos stands these relationships were not significant. Positive influence of soil moisture on the aboveground yearly production was observed only in the meadow community belonging to Cnidion alliance. Consequently, the growth of Calamagrostis epigejos was less limited by both amount of precipitation and soil moisture in comparison with intact alluvial meadow communities.