The Ethnobiological Society of Indonesia (PMEI) today released the final report of its first-year conservation project on Belitung Island, funded by the Rufford Foundation. Running from 1 February 2025 to 30 January 2026, the project focused on two threatened dipterocarp species endemic to the Bangka-Belitung Islands: Hopea bilitonensis (Critically Endangered) and Rubroshorea balangeran (Vulnerable). Following the initial project announcement in September 2025, the team has successfully completed all planned activities, including community surveys, extensive fieldwork across three research sites, and detailed data analysis. The final evaluation confirms that all expected outcomes have been fully achieved.
Figure 1. (a) Hopea bilitonensis, (b) Rubroshorea balangeran
The most significant and unexpected finding was the discovery of Hopea bilitonensis seeds during fieldwork, indicating that natural regeneration of this Critically Endangered species is still possible. The project documented 24 occurrence points for H. bilitonensis and 11 for R. balangeran, recording a total of 452 individual plants across 45 species within 1.4 hectares. Habitat analysis revealed that H. bilitonensis occupies a broader range of elevations (0–195 meters above sea level) and slopes (up to 23%), while R. balangeran is restricted to lower elevations (0–57 masl) and gentler slopes (below 10%), suggesting more specialised habitat requirements. Population structure analysis showed that H. bilitonensis exhibits a reverse-J diameter distribution, indicating ongoing recruitment but limited large-sized adults, whereas R. balangeran lacks small-diameter individuals, pointing to an aging population with constrained regeneration. Importantly, four male members of the local youth environmental group KEPPAK (Kelompok Pemuda Pecinta Alam Desa Kelubi) actively participated in all field activities, gaining practical knowledge and supplementary income while supporting data collection.
Based on the successful first year, PMEI plans to develop a propagation protocol for Hopea bilitonensis using the newly discovered seeds, monitor and collect seeds of Rubroshorea balangeran in 2026, and apply for a second Rufford Small Grant to support propagation and reforestation efforts. The findings will be shared with the IUCN/SSC Global Tree Specialist Group, and a manuscript will be submitted to a peer-reviewed journal. Project Lead Anisa Anggraeni stated, "The discovery of Hopea bilitonensis seeds was a turning point. It shows that natural regeneration is possible, but active propagation is now urgently needed. The willingness of local communities to engage in conservation gives us real hope for the future." The Rufford Foundation was acknowledged verbally throughout the project, and more detailed information, including photographs of the seeds and data analysis, is available in the supplementary report.
Figure 2. Seeds of Hopea bilitonensis (a-d) show different views of the seeds, highlighting their physical characteristics and potential for regeneration