Imbak-Kalabakan
Summary
- Northeast Bornean orangutans (Pongo pygmaeus morio) are present in the Imbak-Kalabakan landscape.
- It has been estimated that 1,570 (CI: 1,037-2,374) individuals occur in the site.
- The orangutan population trend is unknown.
- The site has a total size of 4,805 km².
- Key threats to orangutans are habitat fragmentation and human-orangutan conflict.
- Conservation activities are not documented.
Site characteristics
The Imabalak-Kalabakan region is located in Malaysian Borneo, in the northeastern state of Sabah. The region comprises 2,175 sq.km of protected and 2,630 of unprotected areas (SWD 2020). The vegetation is characterised by a mixture of heath, lowland and upland mixed dipterocarp forests (Simon, Davis & Ancrenaz 2019). Fragmented forests, such as the Brantian-Tantulit virgin jungle, the Ulu Kalumpang Forest Reserve, and oil palm and industrial tree plantations are found in the Kalabakan landscape, where land use continues to change (Phaik Imm et al. 2021).
Table 1. Basic site information for Imbak-Kalabakan
| Area | 4,805 km² |
| Coordinates | 5.013665 N, 117.177508 E |
| Designation | Unclassified |
| Habitat types | Subtropical/tropical moist lowland forest, plantations |
Ape status
A 2017 survey revealed an enormous increase in population size in 15 years, from 313 to 1,570 orangutans (Simon, Davis & Ancrenaz 2019). The population has remained sparse and dispersed over a large area. These higher densities may reflect immigration from adjacent land areas where there has been substantial clearance of forest between the two surveys. The larger population estimate was also due to more intensive survey efforts, and a substantial but scattered orangutan population was probably underestimated in the past (Simon, Davis & Ancrenaz 2019).
Table 2. Ape population estimates in Imbak-Kalabakan
| Species | Year | Abundance estimate (95% CI) | Density estimate [ind./ km²] (95% CI) | Encounter rate (nests/km) | Area | Method | Source | Comments | A.P.E.S. database ID |
|---|---|---|---|---|---|---|---|---|---|
| Pongo pygmaeus morio | 2002-2003 | 262(80–860) | 0.06 (0.02–0.19) | Imbak-Kalabakan, Production Forest | Aerial survey | Simon, Davis & Ancrenaz 2019 | |||
| Pongo pygmaeus morio | 2017 | 876 (579–1323) | 0.33 (0.22–0.50) | Imbak-Kalabakan, Production Forest | Aerial survey | Simon, Davis & Ancrenaz 2019 | |||
| Pongo pygmaeus morio | 2002-2003 | 51 (17–166) | 0.06 (0.02–0.19) | Imbak-Kalabakan, Protected Forest | Aerial survey | Simon, Davis & Ancrenaz 2019 | |||
| Pongo pygmaeus morio | 2017 | 694 (458–1051) | 0.32 (0.21–0.48) | Imbak-Kalabakan, Protected Forest | Aerial survey | Simon, Davis & Ancrenaz 2019 |
Threats
Habitat fragmentation and conflicts with people are the major threats to orangutans in the region (SWD 2020).
Table 3. Threats to apes in Imbak-Kalabakan
| Category | Specific threats | Threat level | Quantified severity | Description | Year of threat |
|---|---|---|---|---|---|
| 1. Residential & commercial development | Unknown | ||||
| 2. Agriculture & aquaculture | 2.1 Annual & perennial non-timber crops | High | Forest loss and fragmentation due to conversion of forest to agricultural land. In Sabah, palm oil accounted for 60% of forest conversion between 1973 and 2015 (SWD 2020). | Ongoing (2020) | |
| 2.2 Wood & pulp plantations | High | Plantations of Sabah Softwoods Berhad (SSB), an industrial tree plantation and oil palm plantation company, are situated within the Kalabakan landscape (Phaik Imm et al. 2021). | Ongoing (2021) | ||
| 3. Energy production & mining | Unknown | ||||
| 4. Transportation & service corridors | 4.1 Roads & railroads | Present, but threat severity unknown | Roads, bridges, dams, and railways split populations into smaller subpopulations and give access to poachers and lead to human encroachment (SWD 2020). | Ongoing (2020) | |
| 5. Biological resource use | 5.1 Hunting & collecting terrestrial animals | High | Hunting due to conflict and for bushmeat (SWD 2020). | Ongoing (2020) | |
| 6. Human intrusion & disturbance | Unknown | ||||
| 7. Natural system modifications | Unknown | ||||
| 8. Invasive & other problematic species, genes, diseases | Unknown | ||||
| 9. Pollution | Unknown | ||||
| 10. Geological Events | Absent | ||||
| 11. Climate change & severe weather | Unknown | ||||
| 12. Other options | Absent |
Conservation activities
Table 4. Conservation activities in Imbak-Kalabakan
| Category | Specific activity | Description | Year of activity |
|---|---|---|---|
| 1. Residential & commercial development | Not reported | ||
| 2. Agriculture & aquaculture | Not reported | ||
| 3. Energy production & mining | Not reported | ||
| 4. Transportation & service corridors | Not reported | ||
| 5. Biological resource use | Not reported | ||
| 6. Human intrusion & disturbance | Not reported | ||
| 7. Natural system modifications | Not reported | ||
| 8. Invasive & other problematic species, genes, diseases | Not reported | ||
| 9. Pollution | Not reported | ||
| 10. Education & Awareness | Not reported | ||
| 11. Habitat Protection | Not reported | ||
| 12. Species Management | Not reported | ||
| 13. Livelihood; Economic & Other Incentives | Not reported |
Challenges
Table 5. Challenges reported for Imbak-Kalabakan
| Challenge | Source |
|---|---|
| Not reported |
Research activities
Documented behaviours
Table 6. Ape behaviors reported for Imbak-Kalabakan
| Behavior | Source |
|---|---|
| Not reported |
External links
Relevant datasets
References
Simon, D., Davies, G., & Ancrenaz, M. (2019). Changes to Sabah's orangutan population in recent times: 2002-2017. PloS one, 14(7), e0218819. https://doi.org/10.1371/journal.pone.0218819
Sabah Wildlife Department (SWD). (2020). Orangutan Action Plan for Sabah 2020-2029. Kota, Kinabalu, Sabah, Malaysia.
Phaik Imm, C., Pei Hue, K., & Nathan, R. (2021). Can the Oil Palm Industry and Elephant Conservation Be Reconciled? A Case Study in Kalabakan, Sabah. Gajah, 53, 30-38.
Page completed by: A.P.E.S. Wiki team Date:22/11/2021