Differential responses of cryptic bat species to the urban landscape

Abstract

Urbanization is a key global driver in the modification of land use and has been linked to population declines even in widespread and relatively common species. Cities comprise a complex assortment of habitat types yet we know relatively little about the effects of their composition and spatial configuration on species distribution. Although many bat species exploit human resources, the majority of species are negatively impacted by urbanization. Here, we use data from the National Bat Monitoring Programme, a long-running citizen science scheme, to assess how two cryptic European bat species respond to the urban landscape. A total of 124×1km2sites throughout Britain were surveyed. The landscape surrounding each site was mapped and classified into discrete biotope types (e.g., woodland). Generalized linear models were used to assess differences in the response to the urban environment between the two species, and which landscape factors were associated with the distributions ofP.pipistrellusandP.pygmaeus. The relative prevalence ofP.pygmaeuscompared toP.pipistrelluswas greater in urban landscapes with a higher density of rivers and lakes, whereasP.pipistrelluswas frequently detected in landscapes comprising a high proportion of green space (e.g., parklands). AlthoughP.pipistrellusis thought to be well adapted to the urban landscape, we found a strong negative response to urbanization at a relatively local scale (1km), whilstP.pygmaeuswas detected more regularly in wooded urban landscapes containing freshwater. These results show differential habitat use at a landscape scale of two morphologically similar species, indicating that cryptic species may respond differently to anthropogenic disturbance. Even species considered relatively common and well adapted to the urban landscape may respond negatively to the built environment highlighting the future challenges involved in maintaining biodiversity within an increasingly urbanized world.