Bat responses to tree species composition and moth abundance in mixed forest landscapes

Par Jérémy Froideveaux (post-doctorant du projet CERES, UMR DYNAFOR).

I will present the 1st results of the fieldwork we conducted in the Cevennes National Park last summer as part of the CERES project. We implemented a paired-sampling design, each pair consisting of a coniferous-dominated stand and a mixed tree stand located along a landscape composition gradient. Bats were acoustically sampled for two consecutive nights at both ground and canopy levels. Nocturnal moths were captured using a portable heath-type actinic light trap. Overall, we recorded at least 13 bat species with 60,143 bat passes. The local species richness ranged from 1 to 10 (mean=6). We captured 16,086 moths that we grouped in three size classes (small, medium, and large). We found significant interactions between tree species composition at landscape and stand scales on bat species richness and bat activity of several species. For moth-feeding bat specialist such as Barbastella barbastellus, we also detected a significant interaction between moth abundance and shrub cover. These interactions will be discussed during the presentation.