The use of acoustic detectors for assessing bat species richness and functional activity in a South African National Park.

Abstract

Insectivorous bats are a difficult group of mammals to survey because they are small, nocturnal, fly and often roost in hard to reach places during the day. However, bats should not be neglected from biodiversity assessments because they play pivotal roles in pest regulation and as biological indicators. We used acoustic detectors to sample bat species richness at three sites within the Mapungubwe National Park (MNP), South Africa during the austral winter and summer of 2013. A minimum of 11 species from six families were recorded, with the clutter-edge foraging bats (Miniopteridae and Vespertilionidae) and open-air foraging bats (Molossidae), dominating. Bat activity was significantly higher in summer compared to winter and this is likely linked to higher prey availability and reduced thermoregulatory costs at this time. Our results represent the first assessment of bat species richness in the MNP and our data compare favourably with historical records for the region. In addition, we provide evidence for the presence of at least one undescribed species. We advocate the use of acoustic detectors for future bat surveys as long as comprehensive reference call library data are available.