Plant community variability within potential natural vegetation units: A case study from the bohemian karst

Abstract

Based on a map of potential natural vegetation (PNV), actual vegetation was studied in the Mramor locality (106.4 ha). A total of 188 relevés were examined using stratified random sampling. A comparison was made between trends in vegetation variability throughout the entire locality and variability within the defined PNV units. The stratification of the locality according to PNV units was only partly representative of the main trends in vegetation variability, especially at ecologically distinctive sites. On the other hand, in areas with a relatively limited ecological gradient, the sites were "oversampled". The variability of plant communities within PNV units was high. The results of this case study suggest that the need for delineation of PNV units which are homogeneous in terms of production, site and phytocoenosis is overestimated. This delineation neither corresponds to the characteristics of actual ecosystems nor is necessary for the application of a PNV system. A more suitable unit for the development of such a system would be, for example, forest type series.