Shed light in the dark – How do natural canopy gaps influence temperate bat diversity and activity?

Abstract

Abstract Globally, forests are under pressure to cope with an increasing human demand for forest products, while the need to protect forest biota increases. Old-growth forests are reference systems for the study of natural structures and processes in forest ecosystems. Results from such studies can be used to derive management practices that support and even foster biodiversity. Most temperate bat species exhibit a high affinity towards forest habitats. We studied the foraging behaviour of temperate woodland bats in naturally created canopy gaps. The study took place in a large and coherent Central European lowland old-growth forest, the “Belovezhskaya Pushcha” in Belarus. We used passive acoustic recorders to assess the activity and diversity of bats in 12 natural canopy gaps and in adjacent forest interior control plots in two different forest habitats. We found that the activity of open-space foragers and narrow-space foragers did not differ between forest gaps and the adjacent forest interior. The activity of edge-space foraging bats was higher in forest gaps. Bat diversity in mixed-coniferous forest stands was higher in canopy gaps. Gap size differently influenced bat guild activity. While the activity of open-space and narrow-space foragers did not vary with gap size, the activity of the edge-space foragers declined in broadleaved forests with increasing gap size. Bat diversity decreased with increasing gap size only in broadleaved forests. Our results demonstrate the differential influence of small-scale disturbances in old-growth forests on temperate bat guilds. Furthermore, our study highlights the importance of native broadleaved forests for the temperate bat community.