Tree-dwelling bats as indicators of forest landscapes

• Barbastelle bats show scale-dependent habitat associations across Italy’s forests. • Barbastelle’s presence links to altitude, beech forests, and deciduous oak. • Negative associations with intensive crops, and fragmented landscapes. • Findings support barbastelle bats as indicators of forest landscape composition. • Future studies should test links to forest management, structure, and deadwood. Adopting standalone indicators to characterise landscape composition is vital because it allows for targeted assessments without surveying entire communities. We hypothesised that barbastelle bat ( Barbastella barbastellus ) presence would provide sufficient indication power to characterise forest landscapes in Italy and employed logistic regression to explore this relationship across the Alpine and Apennine regions. We selected three spatial scales (200 m, 1000 m, and 3000 m). We predicted distinct association patterns across biogeographic areas, sensitivity to multiple spatial scales, strong associations with altitude and specific forest types, and avoidance of intensive agricultural areas. Using opportunistically collected data from non-invasive acoustic surveys, we recorded effective responses despite methodological heterogeneity. We revealed significant positive associations in the Alpine region, with deciduous oak forests at the 3000 m scale, while showing negative correlations with mesophilic and mesothermophilic broadleaved mixed forests. In the Apennine region, albeit at different spatial scales, barbastelle bat presence was strongly associated with altitude, beech forests, and natural grasslands with trees and shrubs. It also exhibited negative associations with intensive crops. Furthermore, barbastelle bats exhibited varied relationships with landscape metrics, such as patch density and landscape evenness, indicating a reduced likelihood of presence in fragmented landscapes, particularly at larger scales. This highlights the complexity of their role in indicating forest landscape structure. Our findings support the potential role of barbastelle bats as reliable indicators of forest landscapes. Future work should test the ability to describe different forest management practices, high-resolution structures, and the amount of deadwood.