BIODIVERSITY CHANGES ON AN ECOSYSTEMIC LEVEL - PHYTOCOENOLOGICAL APPROACH

The biodiversity of a territory on the level of organisms (species poo l) is realized within biocoenoses. The diversity of biocoenoses (coeno diversity) can be studied by means of delimitation, classification and mapping of phytocoenoses which fix terrestrial biocoenoses to the Ear th's surface. The geobotanical research offers two types of evidence a s a basis for this - inventories of vegetation units (syntaxa) and map s of vegetation units. Three geobotanical methods for monitoring coeno diversity changes in a region can be used - 1 repeated inventory of sy ntaxa (associations), 2 repeated vegetation mapping, and 3 long-term m onitoring of plant community and habitat changes on permanent plots. T he actual biodiversity both at an organismal and ecosystemic level is threatened especially by these factors - 1 reduction of biotope divers ity of a landscape by large-scale agricultural management, 2 eutrophic ation ard acidification of soils by acid rains rich in nitrogen, and 3 expansion of aggressive plants into natural and semi-natural plant co mmunities.