During the years 1991-2010 the study was conducted in Łódź province, on post-bog meadows reclaimed in the 60s of twentieth century. Reclamation launched and accelerated the processes of organic matter transformation. Most of the drained meadows were utilized and properly used. Agriculturally valuable communities of class Molinio-Arrhenathereteae have developed there. In the early 90s of twentieth century, in result of failure of maintaining the detailed drainage system and the reduction of meadow technology level, the moisture of post-bog meadows increased. The valuable species of the class Molinio-Arrhenatheretea disappeared or decreased their share in sward. The share of herbs and weeds and/or sedges from wet and marsh habitats increased. Increase of meadow habitats moisture resulted in transformation of wet habitats to reswamped or swamped habitats.