Climate and Forest Cover Explain the Rarity of the Tricoloured Big-Eared Bat (Glyphonycteris sylvestris) in Eastern South America

The tricoloured big-eared bat, Glyphonycteris sylvestris (family Phyllostomidae), is a species frequent in bat surveys of certain Neotropical regions, but rarely recorded in the fragmented forests of eastern South America. The extent to which this lack of records is driven by the species' abiotic niche or its sensitivity to the forest loss observed in the region remains unclear. Here, inspired by new records we have made in the southern Atlantic Forest – including the southernmost – we investigated the role of climate and forest cover in the geographic distribution of G. sylvestris. Using our primary records and data from an extensive literature search, we fitted species distribution models with ecological variables at 1 km2 resolution, while accounting for sampling biases common in opportunistic data. We then used this model to predict the species' distribution in South America under different scenarios of climate and forest cover availability. Our results suggest that both climate and forest cover shape G. sylvestris rarity in eastern South America. Although our model predicts low climatic suitability for drier regions such as the Caatinga and Chaco, it also suggests that this species could be frequent in the Atlantic Forest and in forest formations of the Cerrado if most landscapes had not been altered by human activities in these regions. Our study elucidates the southern distribution limits of G. sylvestris, highlights its vulnerability to habitat loss, and reinforces the importance of landscapes with high forest cover to maintain South American bat diversity.