Does the survival of greater horseshoe bats and Geoffroy's bats in Western Europe depend on traditional cultural landscapes?

Greater horseshoe bats (Rhinolophus ferrumequinum) and Geoffroy's bats (Myotis emarginatus) are two sympatric species that have undergone a serious population decline in Central Europe. In both species, population decline is likely to have been caused by habitat deterioration and habitat loss resulting in a decrease of carrying capacity. We examined the spatial ecology, habitat use and key landscape features in vital populations in R. ferrumequinum and M. emarginatus in the northern part of their current European distribution in Luxembourg. In total, 3,559 fixes from 26 radiotracked individuals were calculated. The tracked individuals of both species showed commuting flights along hedgerows, streams and small-forested patches. Maximum flight distances, home range sizes and habitat diversity did not differ between species, but R. ferrumequinum had significantly larger foraging ranges than adult M. emarginatus. Contrary to other studies, both bat species preferred semi-open, but richly structured traditional farmland habitats such as orchards, pastures and parkland habitats instead of available large broad-leaved deciduous forests. M. emarginatus frequently preyed on abundant arthropod resources in cowsheds, sometimes even exclusively throughout the night. The landscape configuration around the buffered radio fixes of adult R. ferrumequinum and M. emarginatus differed significantly from that around analysed random buffers. Radio fixes were concentrated in a landscape characterised by higher habitat diversity than in the surrounding region. Our results support the concept of a 'biocultural link' between traditional land use and biodiversity, and we therefore strongly recommend the conservation of extensive traditional land use practices, which will help to preserve both endangered bat species along with the local biodiversity.