Vegetation dynamics on fallow agricultural areas in Przemysl foothills [Southeastern Poland]

The studies of fallow lands were undertaken on the Przemyśl hills in the area of Cisowa locality which, till very recently, have been owned by a State Farm (PGR). The objective was to gain insight into the composition and diversification of plant communities on meadows, pastures and fields laid fallow, in context of habitat conditions prevailing after the use had ceased. The study utilised an old cadastral map showing the type of communities by category of use: meadows, pasture, and cultivated fields. The study material consisted of 180 relevés, obtained in the period 1998-2000 using the Braun-Blanquet method. By employing numerical classification, eight plant communities were distinguished, including only two of the association rank: Epilobio-Juncetum effusi, Arrhenatheretum elatioris. The analysis of Ellenberg’s habitat indices proved that all the communities belonged to the half-light vegetation group, occurring mostly on fresh soils, under intermediate moisture-content conditions, more rarely on moist soils which do not dry out. The soil reaction was most often neutral or slightly acidic, and in most of the soils the nitrogen content was in the intermediate range. The two principal trends in the succession of communities in the area, after its farming management has ceased, are: marked increase in species richness resulting from the expansion of species, and the process of overgrowing by woody vegetation.