Mind the gap: Effects of canopy clearings on temperate forest bat assemblages

Abstract

Gaps in the forest canopy appear to play a major role in local species richness as they increase habitat heterogeneity and border effects. In the case of bats, these small clearings seem to play an important role as foraging and commuting sites. However, further research is required to set the actual role of forest gaps on bat biology in order to consider them as conservation targets in forest management. In this study, we test whether bat species richness and activity are higher in gaps within a large Scot pine (Pinus sylvestris) forest than in the adjacent tree covered control sites. We also test these differences in the forest specialists since this group is particularly sensitive to forest management. To investigate this, we used bat detectors in 9 gaps and their adjacent control points during ten nights in July - August 2016 and 2017. The trends resulting from the analysis of 228,108 bat calls support that species richness and activity of bat assemblages were higher in gaps than in the adjacent control points. A similar pattern was detected in the most sensitive tree dwelling bat species. These results stress the importance of gaps as useable areas for the forest bat assemblages and suggest the interest of managing gaps for bat conservation within large areas of continuous tree cover.