Habitat Selections of Himalayan Insectivorous Bats in Forest-Dominated Landscapes

Abstract

The alteration of landscape by anthropogenic activity has reduced the foraging habitats of insectivorous bats. Thus it is important to understand the habitat selections of insectivorous bats and patterns of prey availability, especially in human-altered environments. We investigated bat activity in five classified habitats, namely: old-growth forest, remnant forest, citrus orchard, cornfield and paddy field in the forest-dominated Himalayan country of Bhutan. We monitored bat activity acoustically across 120 sites from May to November 2018. Thirteen different taxa and one unknown QCF bat were identified from 2,558 bat passes. Overall bat activity was dominated by open-space foragers such as Scotophilus kuhlii, Taphozous sp., Otomops wroughtoni and Nyctalus leisleri, showing comparative variations in habitat selection. But, Rhinolophus specifically, R. luctus was rarely present in open habitats such as cornfield and paddy fields, and was found to be one of the most abundant species in cluttered habitats, e.g., old-growth forest and remnant forest. Bat activity was higher in old-growth forest compared to paddy and remnant forest, but was not significantly different from cornfield and citrus orchard. Insect biomass positively correlated with bat activity. Our findings suggest that the habitat selection of insectivorous bats is influenced by prey abundance and habitat types. Although remnant forest was poorly associated with insect prey, the species richness of bats found there was almost equal to that of old-growth forest. Thus, remnant forest was found to be an important habitat, apparently serving as a corridor for the narrow-space foragers in the study landscape in Bhutan.