Preferences of Sumatran orangutan nesting tree at Bukit Lawang Forests of Gunung Leuser National Park

Abstract

Sumatran orangutans (SOUs) are an endemic great ape and the populations are limited distributed at the northern tip of Sumatra as well as recorded as critically endangered, globally. Forest loss and degradations are major causes of the decline of SOU populations from time to time. This research was aimed to identify the preferences of nesting trees of SOU in natural habitat as a consideration in the selection of tree species to restore orangutan habitat. Vegetation analysis using combination line transects and quadrat methods were done at Bukit Lawang Forests (BLF) of Gunung Leuser National Park (GLNP). There was 4 line transects as well as 25 25m x 25m sampling plots were established in each line transects. Each tree in all sampling plots that contain orangutan nests is identified and counted. Based on inventory, there were 121 SOU nests on 58 tree species with 14 tree species classified as preferences of SOU nesting trees. Litsea firma (Lauraceae) was recorded as the most preferences of SOU nesting trees, followed by Knema latericia (Myristicaceae), Cleistanthus sp. (Euphorbiaceae) and three species of Dipterocarpaceae, such as Shorea ovalis, S. parvifolia, and S. leprosula.