The marshland of Villemaur which extends on an area of 22 hectares is registered since 1991 in the inventory of natural areas with ecological interest, faunal and floral. It is one of the last vestiges of the old bogs which enclosed the valley of the valve. It is a refuge for plant and animal species in danger of extinction. Behind the curtain of alders and ash trees there is a large reed bed strewn with birches. Near the river, grazing becomes more humid and reeds leave room for clumps of sedges, cutting flowering plants.