Die Bienenfauna (Hymenoptera, Apidae) im Botanischen Garten Bern (Schweiz)

In 1998 the wild bee fauna at the Botanical Garden in Berne was investigated. A total of 71 species was found, six of which are threatened in Switzerland: In northern Switzerland, Xylocopa violacea is regarded as strongly threatened, Hylaeus difformis, H. punctulatissimus, Andrena viridescens and Bombus humilis as threatened and H. clypearis as potentially threatened. We found 15 oligolectic species, 4 of them feeding on Campanula sp.
15 of the observed species are social. The proportion of soil-nesting species was 40%. 9% were nest-building Bombusspp. and 11 % parasitic bees. The remaining species nested above ground (40%). The soil and sand available under the Lorraine bridge was used as a nesting site by Anthophora plumipes, Andrena carantonica and several other Hymenoptera species.
The species spectrum is compared with the results obtained in other Botanical Gardens, and some aspects concerning abundance, phenology, flower visits and nesting are discussed. The Botanical Garden in Berne, mainly offers habitat for synanthropic species. Besides the food specialists, only few other stenotopic species were found due to the small area and the structure of the garden. Nevertheless, Botanical Gardens offer valuable habitat to wild bees and can play an important role in their protection by providing information for the general public.