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 > Plecotus 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.
The habitat choice of foraging bats depends on the local food supply as well as on vegetation structures that may enable the animals to orientate by echolocation. We examined the associations of bats with different types of landscape elements. Effects of the local insect occurrence, of the canopy structure and of linear vegetation elements on the presence of bats were compared. Bat activity increased with the insect abundance (p = 0.025). Furthermore, regression analysis revealed that bat activity was positively correlated (p = 0.004) with the relative area of open canopy type (clearances, still waters), and vise versa was negatively associated with the area of closed canopy (p = 0.0005). Bat species that predominantly forage in different vertical strata (above or below the canopy), differed in the activity at the various habitat types. Pipistrelle bats and Myotis species favoured open canopy areas (p = 0.007; p= 0.029), whereas Nyctalus species were not significantly more active at this patch type, compared to closed canopy areas (p = 0.0712). Linear characteristics of the vegetation (edges, paths) in general did not regulate the local preferences of bats (p = 0.154), but they corresponded to bat activity in complex structured areas (e.g. clearances with trees; p = 0.008).