Spectral landscapes show that responses to land-use change by aerial insectivorous bats are guild and scale dependent.

Conservation biologists seek unbiased drivers that explain community composition in human modified landscapes. Principal Polar Spectral indices (PPSi), as opposed to patch-corridor-matrix models and thematic maps, produce fine-scale continuous measures of landscape characteristics and generate drivers that can better characterize community composition. We derived ten PPSi metrics based on landscape Brightness and Greenness to determine how habitat heterogeneity molds the composition of two guilds of aerial insectivorous bats at various spatial scales. Insectivorous bats provide crucial ecosystem services; however, it remains unclear what features of the landscape benefit or reduce bat abundance, and at which spatial scales these features impact species composition. We studied a complex agricultural mosaic in the central Andes of Colombia, which ranges from well preserved forests to open-pit mines. We found that species that preferentially forage inside forests or along edges were more abundant at sites with more forest cover across all spatial scales (more Greenness) and less abundant in areas with more exposed surfaces (more Brightness) at the largest scales. In comparison, open space bats were abundant in complex matrices with exposed surfaces but still required forest cover at the broadest scale to maintain abundant communities. Our results highlight that guild and species’ responses to landscape attributes are scale-dependent, and insectivorous bats react to their environment depending on their vagility. We advocate for the use of continuous measures of the landscape, like PPSi, to adequately characterize, manage and protect insectivorous bats in areas undergoing drastic land-use change.