Travel adaptations of Bornean Agile Gibbons Hylobates albibarbis (Primates: Hylobatidae)in a degraded secondary forest, Indonesia

Susan M Cheyne,Claire J.H Thompson,David J Chivers

doi:10.11609/jott.o3361.3963-8

Abstract

Data are presented on the locomotion of Bornean Agile Gibbons (Hylobatesalbibarbis) in a disturbed peat-swamp forest. Our results indicate that gibbons favour continuous-canopy forest, higher canopy heights and trees with a larger diameter at breast height. Gibbons select these trees despite the study site being dominated by broken-canopy forest and small trees. Gibbons also change frequently between brachiation, climbing, clambering and bipedal walking in this disturbed forest depending on the size of gap to be crossed. Gibbons are shown to be capable of adapting to some human-induced disturbances in forest continuity and canopy height, and to the presence of smaller trees, e.g., after selective logging. Despite this, gibbons are still limited to crossing gaps of =12m in a single movement, and more research is needed to quantify levels of disturbance gibbons can tolerate.

Highlights

Data are presented on the locomotion of Bornean Agile Gibbons (Hylobates albibarbis) in a disturbed peat-swamp forest
In this study we provide insight into the actual level of disturbance which gibbons can tolerate by documenting gibbon preferences in a disturbed forest and the long-term implications of forest degradation on gibbon behaviour
Data reported in this study (66%) are closer to those reported by (Andrews & Groves 1976a) for Lar Gibbons (Hylobates lar, 80%)

Summary

Introduction

Data are presented on the locomotion of Bornean Agile Gibbons (Hylobates albibarbis) in a disturbed peat-swamp forest. Our results indicate that gibbons favour continuous-canopy forest, higher canopy heights and trees with a larger diameter at breast height. Gibbons select these trees despite the study site being dominated by broken-canopy forest and small trees. Gibbons change frequently between brachiation, climbing, clambering and bipedal walking in this disturbed forest depending on the size of gap to be crossed. Gibbons are shown to be capable of adapting to some human-induced disturbances in forest continuity and canopy height, and to the presence of smaller trees, e.g., after selective logging. Gibbons are still limited to crossing gaps of ≤12m in a single movement, and more research is needed to quantify levels of disturbance gibbons can tolerate

Methods

Results

Conclusion