What factors limit bat abundance and diversity in temperate, north American urban environments?

Abstract

Urbanization in North America has replaced many pre-existing natural environments with artificial, human-populous environments of low biodiversity. Although some bat species have persisted in urban environments, the overall abundance and diversity of bats within them is low. We examined five factors that may contribute to the low diversity of bats in temperate, North American urban environments: Anthropogenic noise, road infrastructure and traffic, ecological light pollution, plant roost availability and diversity and the distribution and diversity of prey. We present a review of available literature to evaluate how each factor may constrain bat abundance and diversity in urban environments. We found that anthropogenic noise and plant roost availability and diversity were more likely to influence only some species of bats, whereas road infrastructure and traffic, ecological light pollution and the distribution and diversity of prey were likely to influence most species of bats. Generally, the effects of these factors on bats are common among urban environments, but individual species' responses to these characteristics might differ slightly among urban environments. Additional research about the effects of these factors on urban bat ecology, abundance and diversity, combined with the protection and connection of existing natural habitat, and education about bats, would inform efforts to increase the suitability of urban environments for bats.