Janus Pannonius Múzeum Évkönyve 41-42 (1996-1997 )(Pécs, 1998)

Természettudományok - Vargha Béla: Fél évszázad környezeti változásának hatása a Tihanyi-félsziget medveállatka (Tardigrada) faunájára

36 A JANUS PANNONIUS MÚZEUM ÉVKÖNYVE 41-42 (1996-97) Effect of the environmental change during a half century to the Tardigrada fauna of Tihany Penninsula, Central Hungary Béla VARGHA From 430 moss and lichen samples collected at 9 different locations on the Tihany Peninsula between 1990 and 1996, the author showed the presence of 28 Tardigrada species. Out of these, one species {Macrobiotus macrocalix) proved to be new to the Hungarian fauna. The frequency of various Tardigrada species in different habitats and collection sites as well as the species richness of the samples were determined. Tourism to the Tihany Penninsula has considerably increased during the past 50 years, accompanied with a growing level of traffic. Indications of certain climatic changes observed elsewhere in the country, such as the general growth of air temperature and the smaller amounts of precipitation, seem to appear here too. The environmental effects on the composition of the Tardigrada fauna were compared in the case of six sample areas with the investigation results obtained by IHAROS (1947). It has been found that the Tardigrada fauna of areas differing in their exposure to traffic and its harmful effects, had transformed differently. Changes are expressed by the altered number of species, and by the changes in the proportion of same, vanished and newly appeared species. Most of the persistent species are of cosmopolitan distribution, with xerophilous and eurytope characteristics, wide tolerance and high resistance. Further away from the road of traffic, and higher in altitude, the amount of pollutants and thus the number of harmful effects decrease. As a result of the more favourable conditions, the number of species as well as the proportion of same and newly appeared species are higher, and the relative number of vanished species is lower. The most favourable changes have been found in the case of Kiserdô-domb and Nyársas-hegy, while the must unfavourable transformation has been observed in samples from Szarkádi-erdő, Kálvária and the village area. In the areas included in the comparison, a total of 21 species could be detected 50 years ago, while today this number is 26. During a half century 11 Tardigrada species disappeared (52% of the number of species 50 years ago), while 16 species (62% of the number of species today) appeared which had been previously unknown from this area. Although the total number of species has grew during the course of the past 50 years, the composition of the fauna has undergone a considerable degree of transformation: more than 50% of the species have become replaced by others. This phenomenon, which can be attributed to environmental changes during the course of years, should be considered as a serious indication. Presently, 46 species representing 38% of the Hungarian Tardigrada fauna, are known to exist on the Tihany peninsula. Our comparative study on Tardigrada species suggests that the environmental changes of the past 50 years on Tihany peninsula have resulted in a marked transformation of the composition of the Tardigrada fauna there. The results support the recognition of Tardigrada species as reliable bioindicators reflecting changes in the environment not only by exhibiting changes in their abundance and number of species (VARGHA 1997), but also by the transformation of the composition of their fauna. The above facts support the importance of using bioindication methods, call the attention to the necessity of monitoring environmental changes, as well as to the theoretical and practical importance of faunistic investigations and their environmental and health implications. Author's address: Dr. VARGHA Béla H-1097 Budapest Gyáli út 2-6. Országos Kömyezetegészségügyi Intézet Ökológiai Laboratórium