Predictive distribution modelling for rufous-necked hornbill aceros nipalensis (Hodgson, 1829) in the core area of the Western Forest Complex, Thailand

Abstract

The rufous-necked hornbill, Aceros nipalensis (Hodgson, 1829), is listed as vulnerable and is found only in the Western Forest Complex. The objectives of this research were: 1) to estimate the geographical distribution for the rufous-necked hornbill at the Thung Yai-Huai Kha Khaeng World Heritage Site in both the breeding and non-breeding seasons; and 2) to determine seasonal changes in its habitat use. We collated the occurrence records of the rufous-necked hornbill from long-term monitoring data and conducted additional surveys during 2004-2008. In addition, spatial layers for potential environmental variables that might affect hornbill distribution were developed and Maximum Entropy (MaxEnt) modelling technique was used to generate potential distributions. The results indicated that MaxEnt models performed very well and the overall accuracies of the predicted maps in breeding and non-breeding seasons derived from the contingency matrix were 81% and 85% respectively. In addition, altitude and land cover were considered signifi cant variables in the species distribution model. Suitable habitats for the rufous-necked hornbill were predicted in the high altitude evergreen forest and were clustered into three patches in the center of Thung Yai Naresuan West, Huai Kha Khaeng, and along the western boundary of Huai Kha Khaeng adjoining Thung Yai Naresuan East. Suitable habitats covered 11.7% of the world heritage site, of which 6.6% and 9.2% were in the breeding and non-breeding seasons respectively, owing to the fact that the home range during breeding season is smaller compared to non-breeding season. Future conservation efforts should focus on enhancing the connectivity between suitable large and small patches within the distribution range, the installation of artifi cial nests, and patrolling to minimise poaching. © National University of Singapore.