Structure and dynamics of central European amphibian populations: A comparison between Triturus dobrogicus (Amphibia, Urodela) and Pelobates fuscus (Amphibia, Anura)

Abstract

During a long-term study of the amphibian fauna on an artificial island near Vienna (Austria), one isolated site was completely encircled with a permanent drift fence and pitfall traps. Eleven amphibian species occurred at the study site. For the Common Spadefoot Toad (Pelobates fuscus) and for the Danube Crested Newt (Triturus dobrogicus). individuals could be recognized by photographing the highly variable dorsal/ventral patterns. Daily patrols of the drift fence, for 6 years since 1986, enabled us to monitor the demography and dynamics of these two species. For T. dobrogicus, the adult part of the censused population decreased from 207 to 87 individuals during the first 2 years of investigation and then remained stable. Pelobates fuscus showed a constant decrease over 6 years, from 626 to 62 individuals. Juveniles were produced annually; a massive increase in this age class was observed for both species during the period of investigation. Triturus dobrogicus showed higher adult survival than P. fuscus. The constancy of several population parameters of both species may reflect the stability of the cultured parkland habitat in which the study site is located