Urban landscape composition drives species-specific responses of aerial insectivorous bats in an Amazonian megacity

Abstract

Abstract Urbanization profoundly impacts natural landscapes, altering species composition and ecosystem structure. In the Amazon, this process occurs amid large areas of native forest, which may favor biodiversity conservation in urban surroundings. Among tropical vertebrates, bats constitute a functionally diverse group that is sensitive to landscape changes, making them effective models for assessing the effects of urbanization. In this study, we investigated how the activity and foraging behavior of aerial insectivorous bats respond to the structure of the urban landscape in Manaus, Central Amazon. We compared sampling sites in urban forest fragments ( n = 23) with sites in the continuous forest of the Adolpho Ducke Forest Reserve ( n = 5). Activity was measured using acoustic monitoring, considering echolocation and feeding calls. We applied permutation tests to compare bat activity across environments, followed by a sensitivity analysis to assess the potential effects of the unbalanced sampling design, and Generalized Linear Models to evaluate the influence of woody vegetation cover, edge density, landscape heterogeneity, and moonlight intensity on bat activity in urban fragments. Eight species detected at least 10% of the total sites were selected for the analyses; four showed higher activity in urban fragments, two in continuous forest, and two showed no difference between the environments. In urban fragments, woody vegetation cover negatively affected both search and foraging call activity in three of the four species that were more active in urban fragments, whereas the remaining species (four for search calls and two for foraging calls) were not influenced by any of the predictor variables. Our results demonstrate species-specific responses of aerial insectivorous bats to landscape structure, highlighting the importance of considering such responses in biodiversity conservation planning in Amazonian cities.