POPULATION FLUCTUATIONS AND THE SPATIAL HABITAT USE BY AMPHIBIANS IN A HUMAN MODIFIED LANDSCAPE

SUMMARY. In this study we present the start of the breeding season and the long term population fluctuations of amphibians in a permanent pond and a number of temporary ponds in a human modified landscape in the middle section of the Târnava Mare basin. The start of breeding was strongly influenced by temperature in spring. The populations of Hyla arborea and R. temporaria were in decline whereas Pelobates fuscus and Bufo bufo were stable during this time. Pelobates fuscus is represented by a small population and is probably maintained by immigration from other areas. Bufo bufo and P. fuscus use only the permanent pond for reproduction. More egg masses of R. temporaria were found in the temporary ponds than in the permanent pond. The reproductive success was yearly observed in the temporary ponds but not in the permanent pond. We assume that the permanent pond is a source habitat for B. bufo and represents sink for R. temporaria whereas the temporary ponds from the forest represent source habitats for the last species. This and the previous studies on this community suggest that in this landscape, both the permanent and temporary ponds and the landscape connectivity are crucial for the maintenance of rich amphibian communities