Long-term changes of forest vegetation - the comparison of present species composition and biodiversity with the historical records

The thesis presents the results of the research of the long term changes in semi-natural vegetation of lowland woodlands in the forest district Klínec (phytogeographical district Střední Povltaví, Central Bohemia, Czech Republic), which is located between the northeastern part of the Brdy Highlands (Hřebeny) and the Vltava River valley. Research of the long term changes over the past nearly 60 years was conducted by resampling vegetation on semi-permanent plots. Old relevés by V. Samek (1957), which were provided by the Czech National Phytosociological database, were used as reference data. Twenty-nine relevés were resampled, which were located using old data and GIS. The shift to shady plant communities (loss of heliophilous and expansion of shade-tolerant species) was found in the study area caused by higher canopy of tree and shrub layer due to the expansion of deciduous trees. Species richness (alpha diversity) was significantly declined. Homogenization of the vegetation was not significantly demonstrated in study area. Species of nutrient-rich habitats as well as alien and invasive species were expanded and fewer red list species of vascular plants was found. Vegetation change in the area was probably most affected by the change in forest management in lowland woodlands (decline of coppicing), eutrophication (deposition of nitrogen from the atmosphere, runoff from agricultural land) and the effect of forest animals especially wild boars