Die Höhenverteilung der Wochenstuben einiger ausgewählter schweizerischer Fledermausarten (Mammalia, Chiroptera)

Abstract

Nursing of the bat species Rhinolophus hipposideros (Bechst.), Myotis mystacinus (Kuhl), Myotis myotis (Borkh.), Pipistrellus pipistrellus (Schreber), Eptesicus nilssoni (Keys. et Blasius), Eptesicus serotinus (Schreber), Plecotus auritus (L.) and Plecotus austriacus (Fischer) is regularly observed in Switzerland. The nursery colonies of these species are irregularly spread over the studied altitude area. The species can be divided into two types of distribution within the altitude range: 1. Species in which nursing is only proved for a narrow altitude range. 2. Species in which nursing is proved for a wide altitude range. M. myotis, E. serotinus and P. austriacus are reckoned among the first type in the lowlands and E. nilssoni in the mountain region. R. hipposideros, M. mystacinus and P. auritus are reckoned among the second type with a main stress at high and middle altitudes and P. pipistrellus with a main stress al low altitudes. Altitude records reported for hibernating individuals, for captures migrating individuals and even for summer roosts where no nursing occurs may simulate a altitude distribution which cannot be proved with maternity roots distribution. This shows that altitude records, without direct relation to nursing, are meaningless for characterizing bat species as lowland forms or as highland forms and only methods which distinguish between maternity roosts, foraging areas and migration areas should therefore be the basis for estimating the proper distribution area of a bat species. Switzerland is a country with an extremely partitioned landscape and the high human population density in the lowlands may influence the distribution of bats. The ability to nurse over a wide altitude range allows a switchover to suitable nursing places in mountain regions with low impact while those bats which lack this capacity may come into serious conflict with civilisation.