Dieng Plateau
Summary
- Javan gibbons (Hylobates moloch) are present in the Dieng Plateau.
- The population size is unknown.
- The population trend is unknown.
- The survey site has a total size of 175 km².
- Key threats to gibbons are forest fragmentation due to logging and agriculture, and collection of NTFPs.
- Conservation activities are not documented.
Site characteristics
The site consists of a part of a fragmented natural forest in the Dieng Plateau, Central Java province, Indonesia. Dieng is known as a volcanic complex with numerous craters (Widyastuti et al. 2020). The site, which was part of a survey, is located in the northern part of the mountains. The area has hilly terrain, complex riverine, valley, and ridges (Widyastuti et al. 2020). The natural forest in the area is home to a variety of flora and fauna, especially for all primates of Java. Those are Macaca fascicularis, Trachypitechus auratus, Presbytis fredericae, Nicticebus javanicus and Hylobates moloch (Widyastuti et al. 2020).
Table 1. Basic site information for Dieng Plateau
| Area | 175 km² |
| Coordinates | -7.21584 109.90651 |
| Designation | Unclassified |
| Habitat types | Subtropical/tropical moist montane forest, Subtropical/Tropical Heavily Degraded Former Forest |
Ape status
A 2018 survey aimed to identify the habitat suitability model (HSM) for Javan gibbons in the Dieng highland and the most influencing biophysical variables (Widyastuti et al. 2020). A total of 305 occurrence data recorded in extensive field surveys and 11 variables were maintained for HSM in presence-only machine learning, maximum entropy (MaxEnt). Suitable gibbon habitats were predicted as 81.286 km2 in the surveyed area (Widyastuti et al. 2020). Relatively large areas of suitable habitat are located in Sokokembang, Linggoasri-Mendolo, and western of Kembanglangit. The most important variables were natural forest, elevation, distance to cropland and land surface temperature (Widyastuti et al. 2020).
Table 2. Ape population estimates in Dieng Plateau
| Species | Year | Total number indiv. (95% CI) | Total number groups (95% CI) | Density [groups/km²] (95% CI) | Area | Method | Source | Comments | A.P.E.S. database ID |
|---|---|---|---|---|---|---|---|---|---|
| Hylobates moloch | 2018 | 175 km2 | Line transects (Distance) | Widyastuti et al. 2020 | In addition to line transects, faecal samples, vocalisations, and sightings information from trusted villagers were considered as indirect evidence to obtain a robust occurrence data |
Threats
Table 3. Threats to apes in Dieng Plateau
| 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 | Present, but threat severity unknown | Several relatively flat areas converted into cropland, such as dry crop and rice field (Widyastuti et al. 2020). | Ongoing (2020) | |
| 2.2 Wood & pulp plantations | Present, but threat severity unknown | Plantation forest next to natural forest, such as pine tree, rubber tree, and dammar tree (Widyastuti et al. 2020). | Ongoing (2020) | ||
| 3. Energy production & mining | Unknown | ||||
| 4. Transportation & service corridors | 4.1 Roads & railroads | Present, but threat severity unknown | Roads built to support development of tourist parks (Widyastuti et al. 2020). | Ongoing (2020) | |
| 5. Biological resource use | 5.2 Gathering terrestrial plants | Present, but threat severity unknown | Collection of NTFP such as honey (Widyastuti et al. 2020). | Ongoing (2020) | |
| 5.3 Logging & wood harvesting | High | Most of the natural forest patches are secondary forest due to logging in the past (Widyastuti et al. 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
The forested areas at the site are managed by Perum Perhutani (Indonesia state-owned forestry enterprise) which are mainly responsible for forest production (Widyastuti et al. 2020).
Table 4. Conservation activities in Dieng Plateau
| 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 Dieng Plateau
| Challenge | Source |
|---|---|
| Not reported |
Research activities
Documented behaviours
Table 6. Ape behaviors reported for Dieng Plateau
| Behavior | Source |
|---|---|
| Not reported |
External links
Relevant datasets
References
Widyastuti, S., Perwitasari-Farajallah, D., Prasetyo, L. B., Iskandar, E., & Setiawan, A. (2020, February). Maxent modelling of habitat suitability for the endangered javan gibbon (Hylobates moloch) in less-protected Dieng Mountains, Central Java. In IOP Conference Series: Earth and Environmental Science (Vol. 457, No. 1, p. 012014). IOP Publishing.
Page completed by: A.P.E.S. Wiki team Date: 28/01/2022