B. Papp szerk.: Studia Botanica Hungarica 36. 2005 (Budapest, 2005)

Medzihradszky, Zsófia: Holocene vegetation history and human activity in the Kis-Balaton area, Western Hungary

y se the data with this multivariate technique as well (TURNER 1986). In our case the PCA analyses reflected only the main vegetational changes. Palynological richness: The reconstruction of temporal changes in diversity from pollen assemblages is potentially important not only in the palaeoecological studies, but in the investigation of human impact, because community diversity may, in part, result from historical processes (BIRKS and LINE 1992). Dating: The absolute dating of the cores was made in the Laboratory of Environmental Studies, Institute of Nuclear Research of the Hungarian Academy of Sciences using radiocarbon method. The l4

C measures were carried out from the same samples as the pollen analyses to eliminate the possible crawling errors. The calibration of the conventional radiocarbon data was calculated by the Calib Rev 4.4.2 program (STUIVER and BRAZIUNAS 1993, STUIVER et al. 1998a, h). RESULTS Keszthely-Usztatómajor • The studied region is situated in the system of the mire areas of the ancient bays of Lake Balaton in the middle part of the Kis-Balaton and Zala valley swamp-basin, north of the Zala river (lat.: 46°45'46"N; long.: 17°13'30"E). Geomorphologically the mire plain dominates the area, a subtle difference of level 105-107 m a.s.l - is characteristic. Two small islands rise from the plain, the Sziget (120 m a.s.l) and the Cibere hill. Our sampling point is in the plain, between the Hévíz and Usztatómajor channel. Preliminary results were published previously (MEDZIHRADSZKY 2001a, SZÁNTÓ and MEDZIHRADSZKY 2004). Radiocarbon data Eleven datings were made from the whole depth of the profile in approximately equal sequences. Among them the samples deb-5085 and deb-5088 provided incorrect and reversed data, they were omitted from the interpolation of the pollen curve (Table 1). Sedimentation The total depth of the profile is 580 cm and it is entirely a peat deposit. In the Holocene, about the upper 480 cm peat with coarse remains is characteristic. The peat was formed according to the ancient water level from Cladium mariscus, Eupatorium cannabinum and Schoenoplectus lacustris (Table 2).