Nightlife in the city: bat activity in urban vegetation cover gradient

Urbanization is a major driver of biodiversity change, yet its effects on nocturnal fauna remain poorly understood. Bats, as highly mobile and sensitive taxa, are widely recognized as effective bioindicators of environmental quality. In this study, we investigated bat activity and functional behavior across an urban–suburban–rural gradient in Palermo (Sicily, Italy), using passive acoustic monitoring.A total of 340 sampling nights were conducted using AudioMoth devices across three habitat types: urban green areas, suburban transitional zones, and rural environments. Bat activity was quantified through call recordings, while functional behavior was assessed by analyzing feeding buzzes (FB) and social calls (SC). Species identification revealed a consistent community composition across habitats, dominated by Pipistrellus kuhlii, Pipistrellus pipistrellus, and Tadarida teniotis. Species richness remained relatively stable (~2 species per night), and no significant differences in species presence were detected among habitats. Despite this taxonomic similarity, marked differences emerged in functional activity. Urban sites exhibited a significantly higher frequency of feeding buzzes and social calls, indicating increased foraging and social interactions compared to suburban and rural areas, where such behaviors were limited or nearly absent. These results suggest that while urbanization does not necessarily reduce bat diversity, it strongly reshapes ecological functions and habitat use. Our findings highlight the importance of structurally complex and well-connected urban green areas as functional hotspots for bat activity. This study underscores the value of acoustic monitoring in assessing urban biodiversity and provides evidence that appropriately managed urban habitats can support key ecological processes, contributing to biodiversity conservation in human-dominated landscapes.