City lights, moonlit nights: examining bat responses to urbanization and lunar cycles

Urbanization is one of the most abrupt mechanisms of land use change. This process can generate significant impacts on biodiversity, and its effects on bat activity patterns need further exploration due to the importance of these animals in controlling insect populations and maintaining ecological balance. This study aims to evaluate and describe the activity patterns of insectivorous bats in the Brazilian Cerrado, using environmental variables such as moon phase (full and new), season (dry and wet), and the level of urbanization. The level of urbanization was defined through an urbanization index and then classified into urban, suburban, and natural habitats to elucidate the impacts of this process on biological communities. We used ultrasonic recorders to sample insectivorous bats and count passes to measure activity in the study areas. A decrease in the activity of aerial insectivorous bat assemblages in the Cerrado was observed with decreasing urbanization. Additionally, bats exhibited higher activity during dry seasons and lower activity during full moon periods, suggesting lunar phobia. We identified significant effects of the time of night and the season of the year on the detectability of these bats, with a higher probability of detection in the first half of the night and during the dry season. Understanding these patterns in urban areas is crucial in the context of expanding cities. This knowledge aids in the maintenance and protection of insectivorous bat species that are fundamental to the balance of ecosystems and the provision of essential ecosystem services in both urban and natural areas of the Cerrado.