Dr. Fűköh Levente szerk.: Malakológiai Tájékoztató 16. (Eger, 1997.)

SÓLYMOS,P.-NAGY, A.: The recent mollusc fauna of the szársomlyó (S Hungary): spatial pattern and microclimate

the grassland on the top (GRL) has. The S subtype is a general group for xerophilous species which are abundant in the W and the E part too. The microclimate has direct and indirect effects on molluscs. Direct effects are linked with the temperature and the relative humidity of the biotope i. g. in the open areas. The interrelation between the air and the plants has an indirect effect: closed and transitional vegetation can keep a lot of humidity and the active radiation zone is at upper hights, so temperature can stay at lower levels (see SCR in Chapter 3.1). This interrelation is very important, because plants as generative surfaces (Bacsó, N. 1970) generate the microclimate and this microclimate provides many other living organisms, such as plants and molluscs, with proper conditions. Fig. 8. Spatial patterns of the mollusc species: types and subtypes. Legend: filled square means relatively high abundance, crossed square means medium relative abundance, pointed square means relatively low abundance, empty square means zero abundance. 4. Summary On the basis of the two-year investigation of the Szársomlyó the recent mollusc fauna has became well-known. Nine sampling areas were examined. Ranking the frequency per each species, pattern type pictograms could be made. Grouping these pictograms several pattern types and subtypes were separated as ecological groups correlating with plant cover and other factors. The multivariate procedures had the same results. Our microclimatological observations were useful to explain the spatial distribution of the molluscs and to show the microclimatological characteristics of three differing observation points of the same exposure. We stated that the microclimate has direct and indirect effect on the molluscs. For the future we plan to go on with microclimatological observations, but in a smaller scale. Smaller-scale malacological surveys are needed, too in which the main difficulty will be the problem of living and dead individuals.