Die Verbreitung der Geburtshelferkröte (Alytes obstetricans) im Kanton Basel-Landschaft (NW-Schweiz)

Abstract

Distribution of the midwife toad (Alytes obstetricans) in the canton Basel-Landschaft (NW Switzerland). The midwife toad (Alytes obstetricans) is among the most strongly declining of Swiss amphibian species. This article documents the status of the midwife toad in the canton of Basel-Landschaft in northern Switzerland. The survey showed that only a few known populations had gone locally extinct. Many hitherto unknown populations were reported for the first time. Most populations were very small. Regular counts of the number of calling males in the amphibian breeding sites of federal importance show that population counts fluctuated strongly but remained stationary over eight years. The distribution of a pathogenic chytrid fungus (Batrachochytrium dendrobatidis) was also surveyed in order to assess whether it represents a threat for midwife toad populations in canton Basel-Landschaft. The chytrid fungus turned out to be widespread but there was no evidence for chytrid-associated population declines.
Overall, the status of the midwife toad in canton Basel-Landschaft is good. The canton should ensure that the midwife toad remains widespread in its territory because the species is declining elsewhere in Switzerland.