Vegetation of trampled habitats in the Plitvice Lakes National Park in Croatia

The vegetation communities of the trampled habitats in the Plitvice Lakes National Park were studied during 2005 and 2006. With the numerical classification of the releves, six clusters were obtained, corresponding to the following specific communities: cluster 1-ass. Matricario-Polygonetum arenastri- the intensively trampled and grazed habitats; cluster 2-ass. Matricario-Polygonetum arenastri- the only intensively trampled habitats; cluster 3-ass. Coronopodo-Polygonetum arenastri- very intensively trampled and grazed farmyards; cluster 4 -Trifolium fragiferum community-the trampled surfaces of moist habitats; cluster 5-ass. Lolietum perennis- the moderately trampled surfaces of roads and yards; cluster 6-ass. Prunello-Ranunculetum repentis- trampled surfaces of forest roads. The first three clusters belong to the vegetation of intensively trampled habitats of the class Polygono arenastri-Poetea annuae and the last three clusters belong to moderately trampled habitats of the class Molinio-Arrhenatheretea. In the analysis of the ecological factors it is established that separation of the releves is influenced most greatly by the trampling intensity observed in the field, and of the Ellenberg indicator values, the most important are light, moisture, soil reaction and temperature. Using the analysis of the plant functional traits it is established that therophytes, annuals, biennials, species resistant to trampling and grazing, neophytes and archeophytes prevail in the intensively trampled habitats. In contrast, hemicryptophytes, perennials, and indigenous plant species prevail in the moderately trampled habitats. Representation of the C-S-R plant functional types shows also that trampling as a disturbance factor has a large influence on the differences in the releves. In the intensively trampled habitats, there is a large proportion of ruderals, while in the moderately trampled habitats there is a large proportion of competitors.