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

MATERIALS AND METHODS Sampling: The sampling was made by a Russian peat corer which resulted 500 mm long sequences. They were stored at 4 °C until the laboratory work, begun. Subsamples were taken with 5 cm interval, or if it seemed necessary, according to the changes of the sediment. Laboratory methods: The laboratory process was based on the generally accepted acetolysis method for the Holocene peat samples (BERGLUND and RALSKA-JASIEWICZOWA 1986). In case of higher inorganic content it was completed with the density separation technique elucidated by ZÓLYOMI (1952). For calculating the pollen concentration of the samples Lycopodium tablets were used according STOCKMARR (1971). Technical and pollen morphological description: The nomenclature of the families and genera follows SIMON (2000); in case of the names of pollen groups the taxon list of the European Pollen Database was used. The pollen grains were identified by using the keys of FAEGRI and I

VERSEN (1989), MOORE et al. (1991) and the atlases of REILLE (1992, 1995). In some cases special descriptions of pollen and other microfossil types were used (ANDERSEN 1979, BEUG 1961, KEDVES 1982, KOMÁREK and JANKOVSKÁ 2001). To identify highly problematic grains (i.e. corroded, degraded or broken forms) the reference pollen collection of the W. Szafer Palaeobotanical Institute of the Polish Academy of Sciences in Cracow was consulted. Pollen dispersal: The problematics of the short and/or long distance transport of pollen grains are well-known, and have been thoroughly investigated since decades. Having wide experience in this regard and the identification of pollen source are very important for the interpretation of a pollen diagram. Based on the studies of H. Tauber (TAUBER 1965, 1967, 1977), S. Th. Andersen (ANDERSEN 1970) and JACOBSON and BRADSHAW (1981) nowadays we have concrete, measured data for the pollen distribution from the emissive plant. In a closed forest most of the pollen precipitates in a 20-30 m distance, while in an open land, as our study area was, a regional pollen rain (from a 10 km radius) is expected (BERGLUND 1986). Of course, it is necessary to carefully follow the anthropogenic indicators, and take into account that a large portion of herbs and the cereals (except for rye) are insect-pollinated, and the flying ability of their pollen is rather poor. If we identify such pollen types we may conclude that the pollen source is nearby. Mathematical methods, computer analysis: Calculation of pollen percentages, plotting pollen diagrams and the multivariate analyses (principal component analysis, rarefaction analysis, age-depths calibration) were performed using PolPal software (WALANUS and NALEPKA 1999, NALEPKA and WALANUS 2003). Pollen count and determination of local pollen zones: For the better statistical calculation we aspired to calculate the proposed thousand pollen in each samples (BERGLUND and RALSKA-JASIEWICZOWA 1986). To reach this number sometimes counting of 4-5 slides was necessary. The values of each taxa were calculated as the percentages of the sum of trees and shrubs (arboreal, AP) and herbs (non arboreal, NAP) pollen. The pollen of aquatics and the spores of Filicales, as plants with local significance, were excluded from the total pollen sum, their percentage values, however, were related against the sum of AP+NAP. The local pollen zones were determined according to the changes of the main terrestrial taxa (BIRKS and GORDON 1985). The pollen diagrams are represented in two ways, according to depth and according to age. The first is helpful in the investigation of the development of the geomorphology and the hydrological history of the area, while the second one makes it possible to compare the pollen diagrams of different sequences and the coordination of the archaeological periods and pollen data. Principal component analysis: Holocene pollen diagrams showing the vegetation and land use history have many taxa and many samples. The PCA analyses display clearly the variation observable in raw data and draw attention to some data not readily apparent thus it is recommended to anal-