Dr. Fűköh Levente szerk.: Malakológiai Tájékoztató 12. (Eger, 1993.)

I. FINTHA-P. SÜMEGI-G. SZILÁGYI: A New Biotope of Chilostoma banaticum (Rossmässler, 1838) in Hungary and its Nature Conservational Asppects

The area can be characterized by a cool humid microclimate in a lowland situation. The dense vegetation on the edge of the forests, dominant species of which are Helianthus decapetalus and Reynoutria japonica effectively help to maintain this high humidity. The July mean temperature is about 20 °C and the precipitation of the vegetation period exceeds 400 ml. River Tisza itself and also the backwaters on the area increase its humidity, which is remakable even in the dry summer months, thus the surface of the soil is wet throughout the entire vegetation period. In the new biotope of Chilostoma banaticum the following malacofauna has been found till now: Carychium minimum (Müller, 1774) Cochlicopa lubrica (Müller, 1774) Vallonia pulchella (Müller, 1774) Arion subfuscus (Draparnaud, 1805) Zonitoides nitidus (Müller, 1774) Bradybaena fruticum (Müller, 1774) Euomphalia strigella (Draparnaud, 1801) Cepaea vindobonensis (Férussac, 1821) Helix pomatia Linnaeus, 1758 Helix lutescens Rossmässler, 1837 The newly found biotope of Chilostoma banaticum (Rossmässler, 1838) at Tiszabecs is the second occurence of this rare species, having today a dacic distribution, (the other one is the Bagi-szeg Forest near Vásárosnamény [Bába, K. 1967]) in NE-Hungary, and the third known biotope on the Hungarian Great Plain together with that of the Mályvád Forest (Sitke Forest) near Gyulavár (Domokos, T. 1992) It should be emphasized that all the three biotopes are directly affected by river-water. The two sites near River Tisza are on the flood-plain (between the dike and the river), and although the third one, the Mályvád Forest is situated outside the dike, but used as an emergency waterstorage area, thus the connection with te upper parts of River Fekete-Körös is provided. All the fossil, subfossil and recent occurrences of the species are located on the banks of rivers taking their sources in Transylvania and flowing through the Hungarian Great Plain (Tisza, Maros, Fekete-Körös). Thus the newly found biotope near River Tisza confirms the idea, that Chilostoma banaticum was carried from the mountains of Transylvania to establish populations on the plain by the means of the rivers and their floods (Czógler, K. 1935, Bába, K. 1979, Domokos, T. 1987). The population near Tiszabecs might be originated from the N-NE part of the species range, ancestors of which could be transported to the lowland through the „green corridor" on the banks of River Tisza from the high mountains (Máramaros, Gutin, Kőhát, Radnai) of the Eastern Carpathians. In our opinion established populations of this species would be found in the Sub-Carpathian region of Ukraine by which we could follow its migration way and map its range in the Upper Tisza region. Considering the ecological aspects of the species, the new biotope of Chilostoma banaticum is also exceedingly important because human activities (forest clearing, change in the tree species composition, relatively open walnut plantations, weedy vegetation) are extremely powerful in comparison with that of the other two occurences. In spite of these disturbances the population of Chilostoma banaticum seems to be very strong (2-25 individuals/m ). We think the species to be highly sensitive to the humidity of its micro-sur-