Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 71. (Budapest 1979)

P. Komáromy, Zs.: Algal flora of Hungarian sandy soils I. Some algological investigations in Kiskunság National Park, Hungary

ANNALES HISTORICO-NATURALES MUSEI NATIONALIS HUNGARICI Tomus71. Budapest 1979. Algal Flora of Hungarian Sandy Soils I. Some Algological Investigations in Kiskunság National Park, Hungary by Zs. P.-KOMÁROMY, Budapest Abstract — The algal flora of Kiskunság National Park has been investigated since 1976. A total of 108 soil samples were collected and 43 algal species were identified: 30 blue-green, 7 green, 3 yellow-green and 3 diatoma species. On the basis of examination carried out on the spot and in the laboratory, it was ascertained that most of the species were in the vegetative stadium. With 2 figures, 1 plate and 2 tables. In two parts of the Great Hungarian Plain quick grounds can be found originating from the Pleistocene alluvial fan of rivers: Nyírség and Kiskunság (Fig. 1). Both are surrounded with loess, because sand and loess are the two components of the defiational process, deposited by a N and NW wind. The accumulation of the sand and loess took place in three occasions, two already passed in the glacial period and in the Holocene and both are of climatic origin. The third one was anthropogenic and was in close connection with the felling of forests. The quick ground in Nyírség essentially differs from the sand of Kiskunság because the latter contains carbonic acidic lime (STEFANOVITS 1963). The present study deals with the soil algal flora of Kiskunság National Park, established on the sandy ridge between the rivers Danube and Tisza. This land is the Pleistocene alluvial fan of Danube, covered with sand and loess. The alluvial sand river ballast and silt can be found at a depth of 100-300 m (BULLA 1962). According to RÓNAY (1961), the surface of the underground water is under the pressure of rocks weighing heavily on the marginal area (e.g. Gödöllő hills and the „highbank" at Kecel-Baja) so the sheet of water is upsurging under the looser sandy ridge. The mean level of the underground water surface is at a 1-3 m depth (Fig. 2). The air-borne sand is of rough granulation (the percentage of granules, less than 0.01 mm in diameter, is 2-5%), and contains little humus. The occurrence of strange mineral parcels (garnet, ruthenium, olivine, zircon and mica) suggests the origin of the sand. The vertical profile of the soil section is homogenous. The moving sand is on the ground in the neighbourhood of Tatárszentgyörgy, Izsák, Bikatorok, Ágasegyháza, Soltszentimre, Bugac, Fülöpszállás, Jánoshalma and Illancs. The top of the sandhills where the mean level of underground water is deeper than 2.5 m, is covered with grass (e.g. Festucetum vaginatae, Festucetum vaginatae stipetosum) or they are naked macroscopically. According to Soó (1964) the successional series of sand binding process is: Brometum tectorum — Festucetum vaginatae danubiale — Festucetum vaginatae juniperetosum — Festuco (rupicolae )-Quercetum roboris —• Convallario-Quercetum roboris. The dominant sand binding plants are Festuca vaginata, Stipa pennata and Stipa capillata, mosses (Syntrichia sp.) and lichens (Cladonia sp.). Among the sandhills and in the wind-furrows, where the mean level of the underground water reaches the depth of 2.5-1.5 meters, Holoschoenus ramosus and Salix rosmarinijolia are to be found. At 1.5-1.0 m underground water level, swamp meadows occur (Molinio-Salicetum rosmarinifoliae

). There are some characteristic flowering plant species which can be found only in these areas, such as Ephedra distachya, Alkanna tinctoria, Alyssum tortuosum, Achillea ochroleuca (Kitaibeliana) (Soó 1970, 1973). Material and methods — Soil algological studies have been carried on in Kiskunság National Park since 1976. Sampling plots were selected in different plant associations and were visited monthly, or five or six times a year. Each time twenty soil samples were taken (except in some localities, where few samples were collected randomly; these serve as comparative materials). The members of the flowering plants which were in close connection with the sampling places, were registered. Besides the actual soil temperature, moisture content, light intensity and pH value were measured in each case. Ann. Hist.-nat. Mus. Nat. Hung., 71, 1979