L. Hably szerk.: Studia Botanica Hungarica 21. 1989 (Budapest, 1989)

Szerdahelyi, Tibor: Vegetation studies on rocky grasslands in the Pilis Mountain (Hungary) II.

STUDIA BOTANICA HUNGARICA (An tea: Fragmenta Botanka) XXL 1999 p. 27-44 Vegetation studies on rocky grasslands in the Pilis Mountain (Hungary) II. by T. SZERDAHELYI (Received October 10,1989) Abstract: The article contains the second part of cenological investigations on rocky grasslands carried out at 8 sites of the Pilis Mountains in the Pilis Biosphere Reserve in its limestone range. At each of the 8 sites 8-15 samples have been examined and compared with each other according to their floral elements, ecological requirements, life-forms and cenological character. The 100 sample plots were analysed by cluster analysis with the help of computer. INTRODUCTION In part I we examined and compared the flora list and some ecological parameters of two places situated fairly from each other (SZERDAHELYI, 1988). In this paper, cenological investigations were carried out in one habitat at 8 sites and their ecological parameters were compared, too. The place of our investigations was the southwestern slope of Pilis Hill and the slope of the plateau. This part of the hill was chosen because this place is an important habitat in floristic respects (the presence of the endemical species Ferula sadleriana and several Corydalis species and hybrids) and we wanted to make perceptible the occurrence of the degradation. The limestone rock grass communities are rich in species, including several rare plants. In the last years we noticed many changes in the vegetation. Till now many sites were hardly to reach but by building roads, these places became easily accesible. At the same time other areas are closed away from tourists and hang gliders for reasons of preservation. In these places we noticed hard invasional influences, several species appeared in great quantity. At some places the changes in flora have been explained by degradation processes. MATERIAL AND METHOD 100 quadrates of 8 sites, each of them 2x2 m, were sampled according to the Braun-Blanquet method (1964). The number of samples were different in case of sites (8 to 15 samples in at a site). The data were collected from July to August in 1988. The exposition of the slope was