L. Forró szerk.: Miscellanea Zoologica Hungarica 7. 1992 (Budapest, 1992)

Andrikovics, S., Bankovics, A. , Csörgő, T. , Gere, G. , Sass, M.; Török, J.: Hydrozoological characters of a reconstructed wetland

The nature reserve area as well as the reservoir are inhabited by an amphibian fauna which seems to consist of a great number of species and individuals. Out of 11 species found in the nature reserve area only 8 were found in the reservoir as well (Table 1). Fire salamander (Salamandra salamandra) also lives in the nature reserve area. Its occurrence is a surprise because this species inhabits mainly the banks of brooks of Hungarian mountains of medium height. Its presence in the studied area may be explained by the cooler micro-climate of the swamps. Table 1. List of amphibian species collected on the territory of Kis-Balaton Species former Nature Reserve Water-Reservoir Area Salamandra salamandra + Triturus vulgaris + + Triturus cristatus + Hyla arborea + Pelobates juscus + + Bombina bombina + + Bufo bufo + Bufo viridis + + Rana ridibunda + + Rana lessonae + + (Rana esculenta) + + Rana arvalis + + Rana dalmatina + (In our estimation not considered as a distinct species) The amphibians' density seems to be very different in the nature reserve area and for the reservoir. In the nature reserve area the estimated number of frogs were found to be 3500 ind./ha, in the autumn, whereas only 1/10 of the value mentioned above was found in the water reservoir. Just like in the other parts of Central Europe, in the Kis-Balaton area, we registrated the occurence of 3 closely related forms of the water-frogs: Rana ridibunda, R. esculenta and R. lessonae. Because it was impossible to determine morphologically the immature specimens, which constituted a significant part of the sampled water frogs, we applied gelelectrophoretic method and were able to identify 3 lactic-dehydrogenase isoenzymes, characteristic of Rana ridibunda, as well as 3 other isoenzyme variants characteristic of R. lessonae and 1 isoenzyme variant characteristic ofR. esculenta. It could be determined that the territory of Kis-Balaton is inhabited mainly by two parental forms, R. ridibunda and R. lessonae, whereas their hybrid, R. esculenta - contrary to our expectations - proved to be very rare. According to our investigations, Rana lessonae carries a serum-albumine of greater molecular weight, whereas the one present in the serum of Rana ridibunda is of a smaller molecular weight. The albumines found in the sera of Rana esculenta seem to confirm the hybrid characters of these animals. The food consumed by the two dominant frog species (R. arvalis, R. esculenta) constituted - nearly without exception - of terrestrial species. Asellids, amphipods and larvae of dytiscid beetle - as characteristic aquatic prey animals for frogs