Effects of trees and water table level on vegetation of two bogs in Šumava Mountains

Effects of trees and water table level on vegetation of two bogs in Šumava Mountains was studied. One of them, Blatenská slať, is a pristine mire, the second one, Schachtenfilz, was drained at the end of the nineteenth century. 143 relevés (1m2) in two transects were sampled at Schachtenfilz, 45 relevés in one transect were sampled at the Blatenská slať in summer 2008. The level of water table depth was measured and influence of trees was estimated for each of the sample plots. Methods of direct and indirect gradient analysis were used for evaluation of results. The occurrence of trees had greater effect on vegetation than the water table depth, however both factors had significant effect on species composition. They are correlated and together explain a similar amount of variability as is explained by the first DCA axis. Therefore, trees and water table depth are probably the most important factors, which affect the species composition at both localities. The vegetation differs significantly between these two localities and the response of the same species at both localities is slightly different because of the different breadth of their realized niche