Language: German, with trilingual abstract in English, French and German
The present study is the result of a long-term inventory by voluntary bat workers and a six-year study of the first author on behalf of the National Museum of Natural History of Luxembourg. Many data were collected at the Museum through reports of roosts or dead specimens. Furthermore, historic data from the literature and museum collections were evaluated. From 1991 to 1996 the summer distribution (mid-April until mid-October) of bats was investigated, using ultrasound detectors, summer roost checks and mist-netting. This inventory was conducted on the entire national territory (2586 km2) on a 5 × 5 km grid with 2 to 3 observation points per grid.
Summer roost checks were undertaken in 213 church lots and further buildings. Mist netting was carried out mainly in late summer and autumn in front of underground habitats. This method additionally allowed the discovery of several bat species difficult to hear and to identify by detector. The importance of some underground habitats as swarming and mating places was established. One hundred and twenty winter roosts were checked by scientiﬁc collaborators of the Museum. As a result of these studies, 19 bat species were identified in Luxembourg: Rhinolophus ferrumequinum, R. hipposideros, Myotis daubentonii, M. mystacinus, M. brandtii, M. emarginatus, M. nattereri, M. bechsteinii, M. myotis, Nyctalus noctula, N. leisleri, Eptesicus serotinus, E. nilssonii, Vespertilio murinus, Pipistrellus pipistrellus, P. nathusii, Plecotus auritus, Pl. austriacus, Barbastella barbastellus.
Two species, R. hipposideros and B. barbastellus should now be regarded as locally extinct, ten years after the last observation. Except for E. nilssonii and P. nathusii, which were only observed by sight and by detector, all other species were also determined in the hand. M. brandtii, N. leisleri, V. murinus and P. nathusii were reported in Luxembourg for the first time. The combination of all methods for the summer inventory allowed the distribution of most bats species in Luxembourg to be established. Data are insufficient however for some species (M. nattereri, M. bechsteinii, E. nilssonii, V. murinus, P. nathusii) to allow a precise picture of their distribution and conservation status to be given and more detailed studies are necessary.
All bat species are presented in their own sections with a German, French and English summary. The maps of summer and winter distribution in Luxembourg show historic and contemporary observations. After an introduction to the ecology of the species, a short presentation of the situation in Central Europe and especially in the regions neighbouring Luxembourg is given in order to better understand the national distribution patterns and factors threatening bat populations. A preliminary estimation of the conservation status of all bat species identified is given in a Red List to enhance further monitoring and protection measures.