Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 68. (Budapest 1976)

P. Verseghy, K.: Quantitative investigation of xerothermophilous lichens of sandy soil

Fig. 1. Climatogramm of Walter, measured in Alonor, Hungary. However, the micro-climatic effects are more important for lichens than are the macro-climatic ones. It is micro-climatic effects that show best the extreme nature of the environment. In July and August the temperature of the air near the surface of the sand reached 55-66 °C around noon; as a result, the temperature of lichen thallus was similar if not higher. Relative hmidity reached 100 % at dawn and decreased to 35-35% around noon in both communities (GALLÉ 1972-73). Results The production of lichens shows seasonal changes, affected by environmental factors. We have noticed a smaller maximum in the spring and a greater one in the autumn (Fig. 2. 3). The total production of lichens (monthly average) was 1520 kg/ha in the case of Festucetum vaginatae and 1700 kg/ha in Brometum; i. e. it is decreasing with the closing of the garssland (VERSEGHY, in press). It is worth mentioning that the change in the phytomass of the very same species of lichen is different in various associations. The cause of the changes in Fig. 2. Total production of lichens in Festucetum vaginatae association in g/m

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