Vegetation changes in Prague's suburban forest during the last 40 years – Human impact and legislative protection

'Klánovický les' is a large suburban forest on the eastern fringe of Prague, Czech Republic. It is formed by a mosaic of acidophilous oak forests and oak-hornbeam stands. Because of its high diversity of plant and animal species, a nature reserve was proclaimed here in 1982. Of all kinds of human impact (forestry practices, agriculture on adjacent areas, and so forth), recreation activities are those which most markedly influence the forest communities. Because of the easy accessibility from central Prague and the rapid spread of suburbs in neighbouring areas, 'Klánovický les' is frequently used for leisure activities. The aim of this study was to describe vegetation trends in this forest. Species composition in 1961, 1988 and 2002 was compared on the basis of phytocoenological relevés. Negative effects of recreation activities were manifested especially in: (a) ecosystem ruderalization (visible as a spread of nitrophilous species); (b) trampling (and the higher percentage of trampling-tolerant species); and (c) the spread of particular plant groups, e.g., epizoochores. On the other hand, ordination methods showed certain regeneration of plant communities after the protected area was proclaimed. This indicates that usage management (e.g., by the regulation of access to the forest interior, encouraging walking along paths, etc.) could help maintain the vegetation in good condition. Informing visitors about the natural value of this area is therefore of great importance.