Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 77. (Budapest 1985)
P. Komáromy, Zs.: The role of algal synusia of grasslands in successional process in Hungary
speciesnumber 100 90 H 80 70. 60 50 40 30 20 1.0 0 I I Euglenophyta Diatoms Chlorophyta I Cyanophyta astatic salt wet transitional grass-steppe lake mud zone Fig. 2. Change in species number and the percentage of algal phyla on the shore of an astatic salt lake (solonchak soil) of the algal populations changes in the different zones. At the margin of the saline water coccoid blue-green algae were found: Chroococcus minor, Ch. paliidus, Ch. turgidus and various diatoms as Amphora coffeiformis, Cymbella affinis, Eunotia veneris, Gomphonema ventricosum, Nitzschia inconspicua and Pinnularia intermedia. The Aster-Plantago zone and the grass steppe communities were characterized by filamentous species: Calothrix braunii, Lyngbya martensiana, Microcoleus paludosus, Nostoc commune, Phormidium angustissimum, Ph. ambiguum, Ph. autumnale, Ph. foveolarum and Ph. papyraceum. The soil algae occupy the places in which flowering plants can not exist because of the rapid changes of water conditions. Successional processes take place inside the algal synusia. Grass-steppe communities (Festucetum vaginatae danubiale) can also be found on the top and the side of sandhills, where the underground water level is deep and the habitat is extremely dry. Communities with Juniperus communis and/or Populus alba (JuniperoPopuletum albae) possess some more favourable conditions. Seasonality and successional processes of soil algal synusia were examined on a sandhill-side with Festucetum vaginatae danubiale community along a 20-meter transect; soil samples were taken at every 1 meter. The top of the sandhill was covered with Festucetum vaginatae Stipetosum (for about half of the transect) and Festucetum vaginatae Fumanetosum occurred on the side. Air vapour content, air temperature, light intensity, and soil moisture conditions were measured in every case. Leaving seasonality out of consideration, the mentioned ecological factors have a mosaic-like pattern. Species number was high in every sample but it was modest at 8-10 meters where mosses and lichens were dominant among the flowering plants. The percentage of Cyanophyta was high in every sample (Fig. 3). Both the number of species and the number of specimens was the highest between 11-20 meters, where the cover of flowering plants, mosses and lichens were the lowest. The result of the three years long examination suggest that algal synusia both in the Fumanetosum and in the Stipetosum show —beside seasonal changes—successional changes as well.
