Accounting for artificial light impact on bat activity for a biodiversity-friendly urban planning

International audience ; Light pollution constitutes a major threat to biodiversity by decreasing habitat quality and landscape connectivity for nocturnal species. While there is an increasing consideration of biodiversity in urban management policies, the impact of artificial light is poorly accounted for. This is in a large part due to the lack of quantitative information and relevant guidelines to limit artificial light's negative effects. This study investigated the impact of light pollution on bat activity in three large cities while comparing two sources of information on artificial light: the location of streetlights and nocturnal pictures taken from the International Space Station (ISS). We tested the relevance of both sources of information by testing 20 different light variables based on either source of information. We used citizen science data to model the activity of Pipistrellus pipistrellus, a species considered "light tolerant", in response to these variables. Our results show that at the city scale, P. pipistrellus activity is negatively impacted by light pollution whatever light variable was used. This detrimental effect was better described by the variables based on ISS pictures than those based on the location of streetlights. We built this methodology with low data requirement so it can be easily reproduced and used in urban planning. We believe it could help take the impact of light pollution into consideration and promote a biodiversity-friendly management of artificial light