TEMPORAL PATTERNS OF BATS IN THE TOP END OF THE NORTHERN TERRITORY, AUSTRALIA

Abstract

Temporal activity patterns of microchiropteran bats were assessed at 4 scales (hourly, nightly, monthly, and yearly) in the Top End of the Northern Territory, Australia, in relation to biotic (insect availability) and abiotic features in the environment. At the hourly scale we found activity declined throughout the night and was most closely associated with temperature. At the nightly scale we found associations between bat activity, moonlight, and temperature as well as a complex association with both moon phase and time of night. At the monthly scale we found bat activity increased dramatically in October and provide evidence that this was triggered by a combination of changing climatic factors that occur at this time of year in the Southern Hemisphere tropics. At the yearly scale, no overall difference was found in bat activity between years (n ¼ 4) and no associations were found with climatic variables. At all temporal scales we found no significant associations or differences in species richness and only weak or no associations with insect availability. There also was a high degree of variation in bat activity across all temporal scales that have significant implications for surveying and monitoring microbats.