Effects of fine-scale foraging habitat selection on bat community structure and diversity in a temperate low mountain range forest

The evolution of different foraging strategies, corresponding echolocation signals and adaptations of wing morphologies allowed niche differentiation and sympatric foraging habitat use of bat species. We investigated how different habitat selection transferred into sympatric species groups ("bat communities"). The occurrence of bat species at different transects and landscape structures of five sites of a low mountain range forest in the south west of Germany was determined. Species were present at transects in the following descending order: Pipistrellus pipistrellus > Myotis myotis > Nyctalus leisleri > N. noctula > Myotis daubentonii > Eptesicus serotinus > Plecoms austriacus. We analyzed patterns of habitat use and evaluated differences in community structure. Landscape structures (patch types) influenced more than geographical location of sites within the landscape the bat community structure. Bat communities at individual forest sites disaggregated into different smaller species groups of one to at least eight species at different landscape structures. The results confirm previously proposed models of foraging habitat use of bats. Species groups clustered in correlation with the landscape structures "open area" (clearance or grassland), "closed or open canopy forest", and "still water". The highest bat diversity foraged predominantly at open canopy forest, which may fulfil best the requirements of several distinct functional groups (guilds) of bats.