The aim of the study was to assess the diversity of meadow ecosystems and the chemical composition of the meadow flora in a Natura 2000 site called the Pasłeka River Valley, depending on the habitat conditions and management. Physical and chemical properties of the selected habitat components were studied and compared with the calculated bioindicators. Taking into account the dynamics of mursh formation in the organic soil’s topmost layer and the habitat conditions in which such soils occur, grassland growing in areas with different land use was selected for the study. One meadow, lying about 50 m from the Pasłęka River, was cut occassionaly. Another meadow, approx. 150 m from the river bank, was cut once, and yet another sampling site situated at a distance of ca 300 m from the river consisted of a meadow used intensively for hay-growing and as a pasture. The poorest floral composition was found on the wettest soil, i.e. on the occasionally cut meadow located in the nearest vicinity to the river. The available phosphorus content in soil, same as total nitrogen, decreased as the distance from the river increased. At a larger distance from the river, the available phosphorus content of the groundwater decreased and the available potassium content increased. The N-NO3 content in water drawn from the river was more than 2– to 4-fold higher than its content in the groundwater collected under the meadows. The highest content of macro‑ and micronutrients was determined in the plant material from the meadow nearest to the river. The results prove that the developed bioindicators for plants do not always reflect the properties of a habitat.

25.1.2020