Sungai Palin watershed

Asia > Indonesia > Sungai Palin watershed

Summary

• Northwest Bornean orangutans (Pongo pygmaeus pygmaeus) are present in the Sungai Palin watershed.
• The population size is unknown.
• The orangutan population trend is decreasing.
• The size of the site is unknown.
• Key threats to orangutans are road building, forest degradation and logging.
• Conservation activities have focused on community-based forest management.

Site characteristics

The protected areas of Danau Sentarum Wildlife Reserve and Betung Kerihun National Park, in the upper Kapuas watershed, were home to relatively large populations of the Bornean orangutan until the 1990s; from 1973 to 1997 almost 30% of habitat disappeared in and around Danau Sentarum Wildlife Reserve (Yanuar et al. 2020). Orangutans are still encountered in the unprotected areas of Sungai Palin and Nanga Awen, which lie between Danau Sentarum Wildlife Reserve and Betung Kerihun National Park (Yanuar et al. 2020).

Table 1. Basic site information for Sungai Palin watershed

Area
Coordinates	0.946904 N, 112.661879 E
Designation	Unclassified
Habitat types	Peat swamp forest

IUCN habitat categories Site designations

Ape status

A survey conducted in 1991 in Nanga Awen, c. 20 km away from Sungai Palin in the same landscape, recorded orangutan nests along three transects (1.0–1.2 km long, with a total length of 4.3 km). The estimated density was 2.62 (95% CI:1.02-6.72). In comparison, the density for Sungai Palin in 2017 was slightly lower (1.29 individuals/sq.km) (Yanuar et al. 2020).

Table 2. Ape population estimates in Sungai Palin watershed

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 pygmaeus	2017		1.29 (0.51-3.25)		Sungai Palin watershed	Line transects (Distance)	Yanuar et al. 2020	Survey effort:4.5 km. 76 nests were observed.

Threats

Orangutans at the site have been mainly threatened by logging, forest degradation and lack of connectivity between forest remnants. A major threat is also the building of new roads (Yanuar et al. 2020).

Table 3. Threats to apes in Sungai Palin watershed

Category	Specific threats	Threat level	Quantified severity	Description	Year of threat
1. Residential & commercial development		Unknown
2. Agriculture & aquaculture		Unknown
3. Energy production & mining		Unknown
4. Transportation & service corridors	4.1 Roads & railroads	High		Construction of new roads in the area (Yanuar et al. 2020).	Ongoing (2020)
5. Biological resource use	5.3 Logging & wood harvesting	Present, but threat severity unknown		Habitat degradation due to logging; since 2003 a logging concession in the area of the Nanga Lauk village has been inactive (Yanuar 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

IUCN Threats list

Conservation activities

Although protection of the site's forests are under the jurisdiction of the district forestry agency, they are managed by the local community as the Nanga Lauk Village Forest. The community is allowed to only extract non-timber forest products. Including the local community in the management of the forest has helped to protect the orangutans, as evidenced by the fact that logging ceased in 2003 (Yanuar et al. 2020).

Table 4. Conservation activities in Sungai Palin watershed

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

Conservation activities list (Junker et al. 2017)

Challenges

Table 5. Challenges reported for Sungai Palin watershed

Challenge	Source
Not reported

Research activities

Documented behaviours

Table 6. Ape behaviors reported for Sungai Palin watershed

Behavior	Source
Not reported

External links

Relevant datasets

A.P.E.S Portal

References

Yanuar, A., Fehse, J., Chivers, D., & Sugardjito, J. (2020). New estimates of orangutan density in Sungai Palin watershed, Kapuas Hulu, West Kalimantan, Indonesia. Oryx, 54(6), 763-766.

Page completed by: A.P.E.S. Wiki team Date: 25/10/2021