Role of vegetation characteristics on the distribution of three hornbill species in and around Pakke Tiger Reserve, Arunachal Pradesh, India

Abstract

The relationship between various vegetation characteristics and the relative abundance of three hornbill species [Great Pied Hornbill (Buceros bicornis), Wreathed Hornbill (Rhyticeros undulatus) and Oriental Pied Hornbill (Anthracoceros albirostris)] was studied in and around Pakke Tiger Reserve, Arunachal Pradesh. We walked transects (n=11; 22 walks) in three study sites to detect hornbills. Vegetation sampling was done using circular plots (n=33; 10 m radius) at every 400m interval along each transect. Encounter rate (1.5{+/-} 0.188/km) of Great Pied Hornbill (Buceros bicornis) was highest in the protected and undisturbed forest area where food and roosting tree density were also high (114/ha). Oriental Pied Hornbill was common in both the sites within Pakke Tiger reserve near riverine forests (0.75{+/-}0.25/km) and also in the dense undisturbed forest (0.875{+/-}0.226/km). Multivariate analysis revealed that tree density, presence of fruiting trees (utilized by hornbills), canopy cover, and tree diversity in a particular area are the major factors responsible for the assemblage of more than one species of hornbills. The study shows that protection of the forest patches to keep the diversity and density of the tree species intact is crucial for the survival and distribution of the hornbills in the landscape.