EFFECTS OF CLIMATE AND FOOD AVAILABILITY ON JAVAN GIBBON (HYLOBATES MOLOCH) RANGING IN GUNUNG HALIMUN SALAK NATIONAL PARK, WEST JAVA

• Main Author: Simokar, Alina
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/83622
• Institution: Institut Teknologi Bandung

Environmental conditions influence primates’ foraging strategies and ranging patterns. Javan gibbon (Hylobates moloch) is an endemic primate of Java Island, currently living in the remaining forest patches, including Gunung Halimun Salak National Park (GHSNP). Wildlife conservation efforts must be supported by a comprehensive understanding of animal behavior, including their ranging. However, current information regarding the effects of environmental conditions on Javan gibbon ranging remains limited. This study investigated the effects of climate and food availability on Javan gibbon ranging in GHSNP. This research used long-term monitoring data from Yayasan Konservasi Ekosistem Alam Nusantara (KIARA) from January to December 2022. We conducted behavioral observations of three Javan gibbon groups (A, B, and S) through scan sampling and collected monthly plant phenology and daily climate data. The data were then analyzed to: (1) calculate the Javan gibbon activity budget; (2) map and calculate Javan gibbon ranging area, including wilayah jelajah (using minimum bounding geometry and kernel density estimation) and daily path length (DPL) in QGIS v.3.36; (3) calculate food abundance index (FAI); (4) calculate mean monthly temperature and monthly rainfall; and (5) analyze the effects of climate and food availability on Javan gibbon ranging using linear mixed models (LMMs) with lme4 and lmerTest package in RStudio (R v.4.2.3). Results showed that the average wilayah jelajah area and DPL of the Javan gibbon were 38.68 ± 7.17 ha and 3.25 ± 0.30 km, respectively. The highest FAI values for fruits, young leaves, and flowers were observed in September, July, and March, respectively. The average minimum temperature, maximum temperature, and monthly rainfall are 17.77 ± 0.34?; 26.59 ± 0.76?; and 418.23 ± 179.68 mm, respectively. This study found that climate and food availability significantly (p-value < 0.05) influenced how far the gibbons ranged, with some variations between groups. These differences might be due to the distribution of food plants, gibbon foraging strategy, and their responses to changing climate conditions.