Can Pteropus giganteus Brünnich, 1782 co-exist in a human dominated landscape? A case study in Pokhara valley, western Nepal

Abstract

Pteropus giganteus Brunnich, 1782 is the largest species of bat found in Nepal. Among the 20 colonies of P. giganteus recorded in Nepal, Chinnedanda, in the Pokhara valley, has been one of the most important diurnal roost sites for many decades, hosting a colony with up to 500 individuals. The existence of this species in Chinnedanda is threatened due to habitat encroachment and cutting of preferred roosting trees (Bombax ceiba and Dendrocalamus strictus) by local residents. Here we describe the effect of house construction on the colony and its shift from Chinnedanda to Shanti Banbatika, a nearby (4 km away) alternative roost. Monthly roost count surveys were conducted from July 2016 to December 2017 in order to understand the changes in numbers of roosting bats at both sites. Pearson correlation coefficients were calculated to assess the effect of building construction on the colony in Chinnedanda. Our findings indicate that the effects of building construction on the bats roosting at Chinnedanda became significantly more evident after four months of construction and suggest that the cutting of preferred roosting vegetation (Dendrocalamus strictus) for construction of buildings to use as scaffolding resources was the main factor causing the colony to relocate to Shanti Banbatika. Shanti Banbatika is now the primary roost site for P. giganteus in the Pokhara valley. The forest grove at this location should be preserved and human disturbances minimized to maintain it as a suitable roost for P. giganteus in future.