Bat activity and prey density were compared in matched pairs at retention-ponds and neighbouring vineyard sites using stationary bat-detectors and sticky-traps, respectively. To examine if bat activity is related to the number of bat individuals, a thermal infrared imaging camera was used. Pipistrellus pipistrellus, the dominant species, served as an example to assess habitat selection between retention-ponds and vineyards. This was performed by relating foraging activity to the available area available within the potential home-range.
Total bat activity and nocturnal prey density were significantly higher above the retention-ponds than above vineyards. High differences of activity levels between the ponds and the respective vineyard sites were found for Pipistrellus spp. (P. pipistrellus and P. nathusii) and Myotis spp. (M. daubentonii and M. mystacinus), being about 180 times and 50 times higher above the retention-ponds, respectively. A significant correlation was found between recorded bat activity and the maximum number of bat individuals observed with a thermal infrared imaging camera. When relating foraging activity to habitat availability within the assumed home-range of P. pipistrellus, retention-ponds had on average a higher importance as a foraging habitat than the complete vineyard area although they covered less than 0.1%of its area.
This study indicates that artificial wetlands such as retention-ponds provide foraging habitats for bats. Therefore, creation of wetlands in intensively used agricultural landscapes benefits bats.