VEGETATION DIFFERENTIATION AND SECONDARY SUCCESSION ON A LIMESTONE HILL IN SOUTHERN POLAND

Abstract. The vegetation of the SkoHzanka Reserve, situated on a limestone hill near Krakow, was examined over a 30 year period, using the Braun‐Blanquet method. With the help of a numerical classification eight types of grassland communities were distinguished, belonging to the classes Sedo‐Scleranthetea, Nardo‐Callunetea and Festuco‐Brometea, and 11 types of woodland communities, both remnants of ancient woodlands from the classes Querco‐Fagetea and Vaccinio‐Piceetea and more recent woods. In the case of grasslands the results of detrended correspondence analysis (DCA) indicated that the largest variation was associated with the soil type. Woods on sandy soils are very different from those on calcareous soils, and the younger recent woods are very different from the ancient woodlands. An analysis of historical cartographic material and aerial photographs shows that in the last few decades the area of recent woods has increased considerably at the expense of grasslands. Changes in species diversity in the woods during secondary succession and their successional convergence were examined and discussed. It was found that young and mature woods on sandy soils are more similar to each other than young and mature woods on calcareous soils. These differences are mainly related to the fact that many woodland herb species growing in rich, broadleaved ancient woods are unable to colonize recent woods since they have a limited colonization capacity. 1990 IAVS ‐ the International Association of Vegetation Science