Summary

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Southwest Bornean orangutans (Pongo pygmaeus wurmbii) are present in Rimba Raya Biodiversity Reserve.
The orangutan population size is unknown.
The orangutan population trend is unknown.
The total site area is 640 km².
The primary reported threats include peat fires, illegal logging, and encroachment by palm oil plantations.
The main conservation activities have focused on raising awareness in the community and restoring habitats.
The site is a REDD+ conservation area since 2013.

Site characteristics

Rimba Raya lies within Indonesia’s Seruyan District in Central Kalimantan, flanked by Tanjung Puting National Park to the west and the Seruyan River to the east. The district spans roughly 16.5 million hectares and is divided into six subdistricts, with peatlands accounting for about 9.2% of its area. The region’s key agricultural products are oil palm and rubber (Indriatmoko et al. 2014).

Table 1. Basic site information for Rimba Raya Biodiversity Reserve

Species	Pongo pygmaeus wurmbii
Area	640 km²
Coordinates	Lat: -3.0503 , Lon: 112.2542
Type of site	Protected area (Biodiversity Reserve)
Habitat types	Subtropical/tropical swamp forest
Type of governance	Private governance

Types of sites Governance types Habitat types

Ape status

Table 2. Ape population estimates reported for Rimba Raya Biodiversity Reserve

Species	Year	Occurrence	Encounter or vistation rate (nests/km; ind/day)	Density estimate [ind./ km²] (95% CI)	Abundance estimate (95% CI)	Survey area	Sampling method	Analytical framework	Source	Comments	A.P.E.S. database ID
Pongo pygmaeus wurmbii

Sampling methods Analytical frameworks

Threats

Table 3. Threats to apes reported for Rimba Raya Biodiversity Reserve

Category	Specific threats	Threat level	Description	Year of threat
2 Agriculture & aquaculture	2.1.3 Industrial farming (including palm oil)	Present (unknown severity)	Agricultural encroachment by palm oil plantations (Sustainable Travel International 2024).	Ongoing (2024)
5 Biological resource use	5.3 Logging & wood harvesting	Present (unknown severity)	Illegal logging activities reported present (Sustainable Travel International 2024).	Ongoing (2024)
7 Natural system modifications	7.1 Fire & fire suppression	Present (unknown severity)	Peat fires were also documented (Sustainable Travel International 2024).	Ongoing (2024)

Threats

Conservation activities

Table 4. Conservation activities reported for Rimba Raya Biodiversity Reserve

Category	Specific activity	Description	Implementing organization(s)	Year of activity
5 Protection & restoration	5.6 Habitat restoration	Habitat management activities were reported to be present (Sherman et al. 2022).		2013-Ongoing (2022)
4 Education & awareness	Other	Community outreach and capacity building (Sherman et al. 2022).		2013-Ongoing (2022)

Conservation activities

Challenges

Enablers

Research activities

Documented behaviours

Exposure to climate change impacts

External links

References

Sherman, J., Voigt, M., Ancrenaz, M., Wich, S. A., Qomariah, I. N., Lyman, E., Massingham, E., & Meijaard, E. (2022). Orangutan killing and trade in Indonesia: Wildlife crime, enforcement, and deterrence patterns. Biological Conservation, 276, 109744. https://doi.org/10.1016/j.biocon.2022.109744
Indriatmoko, Y., Atmadja, S., Ekaputri, A. D., & Komalasari, M. (2014). Rimba Raya Biodiversity Reserve Project, Central Kalimantan, Indonesia. In REDD+ on the ground: A case book of subnational initiatives across the globe (pp. 348–361). Center for International Forestry Research (CIFOR). Retrieved June 26, 2025, from https://www2.cifor.org/redd-case-book/case-reports/indonesia/rimba-raya-biodiversity-reserve-project-central-kalimantan-indonesia

Page created by: Aime Mizero Date: 2025-05-28