Long‐term effects of annual mowing on plant diversity, community composition, and temporal stability in wet grasslands

Introduction Wet grasslands and fens are biodiversity‐rich ecosystems whose structure and functioning are shaped by disturbance, productivity, and hydrological conditions. Their persistence depends on management. Although mowing is widely used to maintain these habitats, its long‐term effects on species diversity and community composition remain insufficiently understood. Objectives We investigated the effects of annual mowing on species richness, community composition, and temporal β‐diversity in Central European wet grasslands and fens. Methods We analyzed vegetation data collected annually from 2009 to 2023 in paired mown and unmown permanent plots (4 × 4 m) established across eight sites representing three wet grassland types. Species richness, community composition, and temporal β‐diversity, and its turnover and nestedness components, were evaluated using mixed‐effects models and multivariate analyses. Results Mown plots supported higher species richness than unmown plots, with species richness increasing over time under mowing but decreasing under abandonment. Annual precipitation had a weak positive effect on species richness, whereas higher mean annual temperature reduced species richness. Plant community composition was significantly variable between mown and unmown plots, and it followed distinct temporal trajectories. Total vegetation cover affected community composition. Mowing reduced total temporal β‐diversity, species turnover, and nestedness‐resultant dissimilarity, showing more temporal stability of communities. Conclusion Long‐term annual mowing maintains plant communities in wet grasslands and fens by promoting species richness and enhancing temporal stability through reduced species turnover and directional species loss. These findings emphasize that mowing is an effective management tool for sustaining biodiversity in Central European wet grasslands and fens under ongoing environmental change.