In the 50-ty years was performed the regulation of the Łabuńka river and detailed ameliorations in the swampy valley poorly available for agriculture. The majority of meadows was ploved and sown by standard mixtures, prevailed by Alopecurus pratensis for more humid soils and Arrhenatherum elatius for drier ones. During 60-ty years the effects of and amelioration were estimated. Found was that in only several years after an amelioration the swamps processes start to dislodge peat processes, whereas the species composition of meadows undergoes disadvantageous changes in undesirable direction for agriculture. More general data regarding to plant cover of meadows from that period and composition of sown mixtures stated the start point for actual study of meadows complexes. An aim of the phytosociological researches, concluded in years 1987-1988 and again in 1997 was paying an attention on the transformations on the plant cover of meadows in many years after finishing of an amelioration. In general the succession progresses from the Molinio-Arrhenatheretea communities introduced to the meadows during their after amelioration cultivation to the communities of Phragmitetea and Scheuchzerio-Caricetea fuscae classes. Contemporary meadow communities were differentiated by the humidity of habitats, fertilization or its lack and utilization or its abandonment.