Dénes Andrea szerk.: Pécs és környéke növényvilága egykor és ma (Dunántúli Dolgozatok (A) Természettudományi sorozat 12. Pécs, 2010)

Morschhauser Tamás, Oláh Anita, Temesi Andrea és Erdős László: Változások a Tubes karsztbokorerdő-sziklagyep növényzetének határzónájában

288 DUNÁNTÚLI DOLGOZATOK (A) TERMÉSZETTUDOMÁNYI SOROZAT 12 Changes of the boundary between karst shrubforest and closed rock sward vegetation on the Tubes Mountain Tamás MORSCHHAUSER

1, Anita RÓZSA

2, Andrea TEMESI

3, László ERDŐS

4 '^University of Pécs Department of Plant Systematics and Geobotany H-7624 Pécs, Ifjúság útja 6. e-mail: 'morsi@gamma.ttk.pte.hu, 4erdosl@gamma.ttkpte.hu " 3Duna-Drava National Park Directorate 3 H-7625 Pécs, Tettye tér 9. email: andrea.temesi @gmail.hu We examined the temporal changes of a boundary between a karst shrubforest and a closed rock sward on the Tubes Mountain (Mecsek Mts., South Hungary). Study area is situated on a S-facing slope, in a height of about 450 m a. s. 1. A transect was established, running from a closed rock sward (Serratulo radiatae-Brometum pannoniéi) into the neighbouring karst shrubforest (Inulo spiraeifoliae-Quercetum pubescentis). The transect consists of four 16 m

2 plots, two of which were positioned in the rock sward, one in the boundary zone and one in the shrubforest. This study was made in the years 2005-2007, with the methods of a former research carried out at the same place from 1991 to 1994 (BORHIDI et al. 1999a, b). The greatest change that can be observed is the expansion of the karst shrubforest at the expense of the rock sward. The species number has decreased in the forest patch, while it has not changed considerably in the other quadrates. Abundances of some species have suffered great changes. Cover of the canopy layer has increased, mainly due to the intensive growth of Fraxinus ornus, that is accompanied by the formation of an edge (mainly Artemisia alba ssp. saxatilis). Abundance of the grasses characteristic of the rock swards has dropped where canopy cover has increased. In contrast, their cover has increased where trees are not expanding. Boundary has become sharper than it was at the beginning of the study.