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 30-t V 74% V 84% V t 25 °C t 25 °C t 1 12,000 Lux 1 11,400 Lux 1 N 1.9% w 5.7% w 80% 23 °C 13,000 Lux 5.3% Fig.3. V 84% t 26 °C 1 11,200 Lux w 2.3% 12 3 H Cyanophyta 5 6 7 ^ others 9 10 11 12 13 14 15 16 17 18 19 20 speciesnumber 30* Flg. 4. V 70% t 33 °C 1 24,000 Lux w 0,2% 80% 31 °C 12,000 Lux 0.9% V 80% t 32 °C 1 20,000 Lux w 0.3 % V 90% t 31 °C 1 16,000 Lux w 0.5% n aűUű n 10 11 12 13 14 15 16 17 18 19 20 Fig. 3. Change in species number and the number of Cyanophyton species along a transect with mosaic-like pattern on calcareous sandy soil. Abbreviations : v = air vapour content, t = temperature, 1 = light intensity, w = soil water content. — Fig. 4. Change in species number and the number of Cyanophyton species along a gradient on calcareous sandy soil Decrease in number of algal species and in the percentage of Cyanophyta and the appearance of diatoms indicate a higher successional stage of community. Algologically the occupation by mosses and lichens also means another successional stage. The soil-binding effects of algal crusts can be pointed out both in the early and in the late phases of succession. There may be situations in the Junipero-Populetum albae community when air vapour conditions, air temperature, light intensity and soil water content are found along a gradient. The structure of ecological conditions is reflected by a characteristic structure of the algal synusia. The algological examinations were made along a 20 m transect, where air vapour content and soil moisture content increased, light intensity and air temperature gradually decreased from 0 m to 20 m. At high light intensity and temperature (coinciding with low air vapour content and dry sand) the percentage of Cyanophyta was high. Where air temperature and light intensity were moderate a transitional zone developed with high species number because of the appearance of green algae. At the end of the transect, where Populus alba was dominant, the number of algae decreased and the blue-green algae disappeared. The maximum of individual and species number of Cyanophyta coincided with the maximum
