Impacts of bat use of anthropogenic structures on bats and humans

Human-induced landscape modifications and climate change are forcing wildlife into closer contact with humans as the availability of natural habitats decreases. Although the importance of anthropogenic structures for the conservation of species is widely recognized, negative narratives surrounding bats may impede conservation efforts in human-dominated landscapes. We conducted a global systematic literature review to summarize research pertaining to bats in anthropogenic structures and analyze the impacts of occupancy of these structures on bats and humans. We extracted data from 735 publications and included 8 that provided a total of 29 quantitative estimates in meta-analyses assessing the consequences of roost selection by bats in anthropogenic and natural habitats. Additionally, information from all 735 publications was used for summaries. Research focused on the Northern Hemisphere, despite the highest diversity of bat species occurring near the equator. Of the 13 identified impacts on bats from the use of anthropogenic structures, disturbance (caused by, e.g., visitation, renovations, artificial lighting) was the most frequently reported. Effects of bat presence on humans were primarily associated with pathogens or other microorganisms of zoonotic interest. Buildings were the most frequently identified anthropogenic roost, and the use of buildings differed across biogeographic realms. Although impacts varied across realms and structures, the Nearctic and Palearctic had the highest incidence of impacts. Few studies compared anthropogenic roosts with natural roosts, but our meta-analyses broadly identified differences in the effects of artificial versus natural roosts on bat behavior, roost temperature, and bat health and occupancy. We found that research is not focused currently on areas where bat-human interactions are most likely to intensify with the growing rate of urbanization. Although many effects on bats from roosting in anthropogenic structures were documented or mentioned, most studies did not measure these effects and few compared them with natural roosts. Quantifying impacts could help in the design of management practices that would benefit bats and humans.