The importance of forest structure on primate distributions in Sikundur, Sumatra, Indonesia
Start date: 15 December 2014
Forest ecosystems are being increasingly altered by human activities and understanding how these systems will respond to changes in their environment is a vital step in preserving biodiversity in these regions. Only 3.8% of Indonesia’s remaining forests are classified as primary, with logging being the primary cause of habitat loss and degradation. Logging creates critical problems for arboreal animals, such as primates, as it creates gaps within the canopy and results in fragmented forests. A direct consequence of fragmentation for primates is increased energy expenditure as their direct route of travel is impeded by the presence of gaps. Primate species have been well studied, however, to date, little data is available on the effects of forest structure on primate populations. This study aims to link forest structure to primate distributions in a field site located in the Sikundur region of the Gunung Leuser National Park, Northern Sumatra. White-handed gibbons, Hylobates lar, and Thomas langur monkeys, Presbytis thomasi, are both arboreal primates occurring sympatrically in the study area and will be the focus of this study. It is expected that these primates would prefer forest types with continuous canopies and a higher proportion of emergent trees. The study area includes primary forest, regenerating forest and old logged forest. Primate densities in these three forest types will be estimated using auditory sampling methods. Vocalizations will be recorded at fixed listening posts within each forest type. Forest structure will be quantified within 50x50m vegetation plots along 2.5km transects, using methods adapted from Manduell et al. (2012) to collect data on tree and canopy characteristics. The results of this study can help to inform future policies on efficient, successful conservation for a highly-valued ecosystem.