Wildlife use of anthropogenic structures: a comprehensive review of bridge use by bats

Human alterations of landscapes, such as habitat conversion and infrastructure buildouts have caused population declines and extinctions of numerous species. Anthropogenic change negatively impacts surrounding landscapes, but in some cases, lead to an increase in synathropy. Bats are one such group that often take advantage of human altered landscapes, roosting in anthropogenic structures such as buildings and transportation infrastructure. However, less is known about how non-traditional or artificial roost sites may affect persistence of synathropic bat species. We conducted a literature review to evaluate the ecological relationship between bats and artificial roosts, specifically transportation structures, as they are often the only roost structures available in some landscapes. Our evaluation revealed that numerous studies on artificial roost selection have been conducted in the eastern region of North America, as well as abroad. Use of transportation structures by bats varies across landscapes, specifically due to variation in annual climate, availability of natural roosts, and bridge structure design. This review enhances our understanding of bat roost ecology, possible pitfalls of synanthropic behaviour, and identify trends related to bat-bridge associations that may improve conservation outcomes for synanthropic species.