In January 2026, the Research and Conservation Team of PT Restorasi Ekosistem Indonesia (PT REKI) is conducting a population and habitat survey of agile gibbons (Hylobates agilis) in Hutan Harapan, Jambi and South Sumatra, Indonesia. Using vocal count triangulation and habitat transect methods, the team assesses distribution and group density to update critical baseline data collected in 2023. 

According to the 2023 survey, agile gibbon groups are distributed across the landscape at a density of between 3.6 and 5.1 groups per square kilometer — a range that translates, in the aggregate, to somewhere between 2,578 and 3,621 groups. The habitat, for now, is holding. Researchers have identified at least 28 species of food plants available across the area, which is to say the forest is still offering what a gibbon needs. 

Preliminary analysis indicates that population patterns remain relatively stable compared to previous records. This finding reinforces the need for continuous monitoring to detect early ecological changes. “Ensuring long-term data consistency allows us to better respond to habitat disturbances and human pressures,” the team emphasized. 

Beyond data collection, this initiative reflects a collaborative conservation approach involving several stakeholders, strengthening protection efforts while aligning with national biodiversity regulations. As the survey continues, the results will refine population estimates and further enhance monitoring protocols for long-term conservation planning in the Hutan Harapan landscape.