Habitat use and temporal activity of the Big Crested Mastiff Bat (<i>Promops centralis</i>, Molossidae) along an urban-natural gradient: a bioacoustics approach

Abstract Urbanization is a prominent demographic process that can transform the landscape and create environmental gradients into natural environments. Cities can provide roosts for many bat species, while others avoid these anthropized environments. Therefore, species-specific studies are needed to understand the responses of bats to urbanization. Promops centralis is a poorly known Neotropical bat that occurs in a wide variety of ecoregions and habitats including cities, making it a good study model. Our main goal was to assess habitat use and temporal activity patterns of this bat across an urban-natural gradient using acoustic data. We also evaluated the use of acoustic space and relationships with sympatric and similar species, such as P. nasutus, Molossops temminckii, and M. neglectus. To our knowledge, this is the first study that uses acoustic monitoring to assess the habitat preferences of bats in Argentina. In 2,535 minutes of recording, 142 P. centralis passes were detected. Data were collected for all habitats (urban, grassland, forest) and for 3 time periods distributed at the beginning, middle, and end of the night. We were able to detect higher levels of activity of P. centralis in grasslands followed by urban habitats and forest, indicating a strong habitat preference at the landscape scale. We also found changes in echolocation behavior in response to habitat, specifically between grassland (open habitat) versus forest and urban (closed habitats), demonstrating echolocation plasticity and ability of the species to explore urban habitats. We found a peak of activity during the first 3 h of the night and a decrease the rest of the night, providing evidence of a unimodal pattern. Lastly, we observed a clear segregation in the acoustic parameters of P. centralis and its sympatric species. Interestingly, when there is overlap in the acoustic parameters of calls between species they emitted pulses with opposite modulation, suggesting a possible segregation mechanism.