Food or urbanization? Assessing the diversity of urban insectivorous bats in a Neotropical city

Urbanization generally has a negative effect on wildlife, including bats. The decline in particular insectivorous bat species, richness and abundance in urban environments is well known; however, the effect of urbanization on diversity is poorly understood. To explain this, we evaluated the effect of urban noise (dB) and artificial light (lux) as a proxy to urbanization, and resource availability, on insectivorous bats. To evaluate which of these drivers best explains the richness, abundance and diversity of urban insectivorous bats, acoustic sampling of the bat community was conducted in Morelia, Michoacán, in three habitat types with varying degrees of urbanization (urban, urban park, transition). The results showed a diverse community (14 species and 3 genera), where the most abundant species, regardless of the degree of disturbance, were Promops centralis and the genus Molossus , which are insectivorous bats known for their adaptation to urban environments. The abundance of insectivorous bats was higher in urban parks, richness did not differ and diversity was higher in transition sites. Despite this, differences among conditions were evident in species composition. Abundance and evenness were best explained by resource availability, while richness and diversity, were equally explained by urbanization and resources availability, which would indicate that the join influence of both is an important condition that can modify urban bat communities.