Roost site characteristics and habitat associations of bats (Mammalia: Chiroptera) in Kamrup District, Assam, India

Chiroptera play vital ecological roles as pollinators, seed dispersers, and insect population regulators; however, information on their roost site requirements remains limited in many parts of northeastern India. The present study examined roost site characteristics and habitat associations of Chiroptera in Kamrup District, Assam, India. Field surveys conducted from November 2019 to March 2025 documented 16 roosts across nine locations, including natural substrates (trees, leaves, tree cavities and bamboo internodes) and artificial structures (houses and building crevices). A total of 115 roosting trees belonging to 12 families, 20 genera, and 23 species were recorded, including two unidentified species and three dead trees. Statistical analyses showed significant positive relationships between bat abundance and tree height, bole height, and crown height, while multiple linear regression indicated that tree height and bole height were significant predictors of bat abundance; crown height was not a significant predictor. The regression model explained 28.2% of the variation in bat abundance (R² = 0.282, P < 0.001). Bat abundance did not differ significantly between evergreen and deciduous trees, whereas significantly higher abundance was recorded on exotic than native tree species (P < 0.001). Bat abundance was negatively correlated with distance from human settlements (r = −0.325, P < 0.001) and water bodies (r = −0.348, P < 0.001). The study provides detailed information on roost site characteristics and habitat associations of Chiroptera in Kamrup District and underscores the importance of retaining mature trees, standing dead trees, bamboo stands, and suitable anthropogenic roosting structures within human-modified landscapes.