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

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

southwest with a gradient of 30-50°. (see Table 1.) We marked 8 sites in this rocky grassland similar to each other in many characters. First SOÓ presented data about this association of „Carex humilis- Festuca sulcata-Stipa joannis association complex" (1930). Later this association was described as Cleistogeno-Festucetum rupicolae by SOÓ (1964-80). This association is in connection with POLGAR's paper with his floristic list (1933). In the fifties', MÁTHÉ (1956) and ZÓLYOMI (1958) gave details about this association. In his paper ZÓLYOMI gave a floristic list from a „Diplachno-Festucetum sulcatae matricum" association of the Buda Mountains. The distribution of the floral elements, cenological character and life-forms of the species can be seen in Fig. 1-3. In Fig. 4 we used the ecological parameters as given by SOÓ (1964-80) and PRISZTER (1985). The notation is as follows: R (soil requirement), T (temperature requirement), F (water requirement), N (nitrogen requirement). The cover values were transformed according to the van der MAAREL method (1979), to render them suitable for analysis by a computer programme. The data of the sample plots were processed by the help of computer, using Czekanowski's index of similarity in a cluster analysis (see the dendrogram in Fig. 8.). The programme used PODANI's Syn-Tax III methods (1988). The arrangement of the samples is as follows: site I with samples 1-10, site II with samples 11-25, site III with samples 26-40, site IV with samples 41-55, site V with samples 56-70, site VI with samples 71-82, site VII with samples 83-91, site VIII with samples 92-100. Abbreviations on Fig. 1: A - Circumpolar, B - Continental, C - Eurasian, D Mediterranean, E - Submediterranean, F - European, G - Central-European, H - South Eurasian, K - Pannonian, L - Balkan, M - Pontian, O - Carpathian, P - other e. g., East Alpine, Sarmatian, Cosmopolitan species. Abbreviations on Fig. 2: A - indifferent, B - Festuco-Brometea, C - Festuco-Bromea, D Festucetum valesiacae, E - Festuckon rupicolae, F - Festucion vaginatae, G - Asplenio- et Seslerio-Festucion, Seslerio- et Bromo-Festucion, H - Quercetea, K - Querco-Fagea, L Fagetalia, M - Tilio-Acerion, N - Orno-Cotinion, O - others e. g., Prunetalia, Secalietea, P Seslerio-Festucion pallentis species. Abbreviations on Fig. 3: Th - therophyton, TH - hemitherophyton, G - geophyton, H hemikryptophyton, Ch - chamaephyton, N and M - phanerophyton species. RESULTS The rock grass communities are very sensitive to degradational occurrences (e. g. treading). On the base of our observations we noticed that where tourism is advanced, the degradational processes appear immediately. This process could be indicated at several species (e. g. Sideritis montana, Agropyron repens, Chondrilla juncea, Bromus japonicus, Bromus squarrosus). At the habitat of Ferula sadleriana the result of fencing in important species immigration started (e. g. Centaurea micranthos, Arrhenatherum elatius, Agropyron repens). This immigration would make a new balance approaching the original conditions. The distribution of the phytogeographical spectrum could be seen in Fig. 1. The quantity of Mediterranean (D), Central-European (G) and cosmopolitan, adventive (P) elements are different at the 8 sites. There is no difference in the quantity of other elements. The continental (B) elements are missing at site I. Observing the distribution of the cenological character on Fig. 2, the quantity of the indifferent (A) elements is the highest at site III. The level of the Festuco-Bromea and