Tree- and Stand-Scale Roost Selection and Partitioning by Bats Barbastella barbastellus Schreber, 1774 and Pipistrellus pygmaeus Leach, 1825 in a European Lowland Forest (dataset)

Our research focused on the roost preferences of two bat species in a forest environment.Throughout the Anthropocene, people have heavily altered the landscape. Forested habitationhas declined, with remaining forests becoming fragmented and often deprived ofold trees that provide shelter opportunities for bats. TReMs (tree-related microhabitats)are essential for forest-dwelling bat species as they provide an opportunity to roost andshelter. Following an infestation of Ips typographus L., the Białowie ˙za Forest is saturatedwith dead spruce trees. We investigated roost selection in two forest-dwelling species, Barbastellabarbastellus and Pipistrellus pygmaeus. To examine similarities or differences in roostselection between species, we radio-tracked 24 barbastelles and 13 soprano pipistrelles overthree breeding seasons. We located a total of 48 barbastelle roosts and 15 pipistrelle roosts,together with the characteristics of the surroundings. We found that barbastelles selectroosts almost exclusively in dead spruce trees (43/48), while pipistrelles selected roostspredominantly in live (n = 8) and dead (n = 5) broadleaved trees. Our results show thatboth bat species have clear differences in roost tree preference. In our study area, with anabundance of exfoliating bark, barbastelles showed a preference for roosting under flakingbark despite the availability of crevices within broadleaved trees. Our findings provideuseful insight into forestry practices, highlighting the importance of standing dead trees.