Somogyi Múzeumok Közleményei 17/B. - Természettudományi tanulmányok (2006)

Farkas, Sándor: The terrestrial Isopod Fauna of South Transdanubia (Hungary) - Dél-Dunántúl szárazföldi ászkarák (Isopoda: Oniscidea) faunája

166 FARKAS SÁNDOR did not support his statement (FORRÓ and FARKAS 1998). It is one of the rarest species throughout the country. During my survey, a few specimens were pointed out from several sites and proved to be characteristic species of the fresh, hazy oak woodlands. In Hungary the natural woodlands had often been replaced by the introduced black locust plantations and due to this process the original fauna annihilated in these sites. Its species set consists of roaming isopods of the neighbouring biotopes. Probably this could be the reason that unexpectedly many species (17) were sampled in this dry habitat type. The characteristic isopod species for this habitat type, T. nodulosus is a xerophyl species that usually inhabits the dry, warm habitats (GRÜNER 1966). The black locust plantation may be suitable for this species because of its loose canopy that transmits more light to the ground level than compared to other woodland habitats. All introduced species live exclusively in synanthropic habitats. However, only two of them (P. pruinosus, P. vulcanius) proved characteristic that could be explained by the inconsiderable distribution data of the other species. Although, P. hoffmannseggii belongs to this group, it does not still connect to the artificial habitats but lives in ant nests that usually occur around houses and in backyards. By GRÜNER (1966), the eastern border of occurrence in natural habitats of P. scaber extends from the Baltic states to the North Balkan. Probably the continental climate of South Transdanubia could be the main reason that does not allow the survival of the species in natural biotopes. H. vividus, C. karawankianus, P. franzi and P. recurvation may also have special habitat preferences but to answer this question requires more investigations. Conclusions Thirty-one terrestrial isopod species were pointed out from a poorly known area of Hungary. P. franzi, P. vulcanius and A. nasatum proved to be new species for the Hungarian fauna. The most common isopods in South Transdanubia are A. vulgare, T. rathkii, P. collicola and H. riparius, while the rarest non synanthropic species are P recurvatum and P. franzi. The distribution area of the majority of species that live in natural habitats extends from Central Europe to the Balkans. Twenty-nine percentage of the species are synanthropic. The following species have significant habitat preference: A. zenckeri (marshes), L. minutus (fresh, humid oak woodlands), P politus (closed, dry oak woodlands), P. collicola and T. nodulosus (black locust plantations), A. roseus, C. convexus, H. mengii, P. hoffmannseggii, P. scaber, P. pruinosus and P. vulcanius (synanthropic sites). Acknowledgement I wish to thank Edit VADKERTI and Levente ÁBRAHÁM Ph.D. for his helpful comments on the manuscript. Further thanks to Zoltán HILLER for reviewing the English translation. The research was supported by the Hungarian Academy of Sciences (Bolyai János Research Scholarship; BO/00304/01).