Summary

Northeast Bornean orangutans (Pongo pygmaeus morio) are present in the Ulu Segama-Malua landscape.
It has been estimated that 2,580 (CI: 1,295-5,866) individuals occur in the site.
The orangutan population trend is unknown.
The site has a total size of 2,400 km².
Key threats to orangutans include logging, forest degradation and fragmentation.
Conservation activities have focused on habitat restoration.

Site characteristics

The Ulu Segama-Malua (USM) landscape is located in the Malaysian state of Sabah between 116°28′E and 4°14′N and comprises approximately 240,000 hectares of lowland forest (WWF 2020, Ancrenaz et al. 2010). The site sustains one of the largest orangutan populations in Sabah (WWF 2020). To the north of USM, Bukit Piton Forest Reserve (12,000 ha) is found, which is an area of high conservation value (WWF 2020). The USM landscape consists of a variably steep terrain, with many hills and ridges, although Malua's topography is predominantly flat and low (Ancrenaz et al. 2010).

Table 1. Basic site information for Ulu Segama-Malua

Area	2,400 km²
Coordinates
Designation	Unclassified
Habitat types	Subtropical/tropical moist lowland forest, Subtropical/Tropical Heavily Degraded Former Forest

IUCN habitat categories Site designations

Ape status

Surveys in 2002 and 2007 show that orangutan populations can be maintained in forests that have been lightly and sustainably logged (Ancrenaz et al. 2010). However, in heavily logged forests there was a decline in orangutan numbers (Ancrenaz et al. 2010). Nest distribution in the forests of Ulu Segama Malua indicates that orangutans leave areas undergoing active disturbance, reaching forests that are located up to 500 meters above sea level (Ancrenaz et al. 2010).

Table 2. Ape population estimates in Ulu Segama-Malua

Species	Year	Abundance estimate (95% CI)	Density estimate [ind./ km²] (95% CI)	Area	Method	Source
Pongo pygmaeus morio	2002	4,584 (2,064-11,064)		Segama forests	Aerial survey	Ancrenaz et al. 2005
Pongo pygmaeus morio	2007		1.52 (0.5-4.1)	North Ulu Segama	Aerial survey	Ancrenaz et al. 2010
Pongo pygmaeus morio	2007		0.13 (0.04-0.39)	Segama East	Aerial survey	Ancrenaz et al. 2010
Pongo pygmaeus morio	2007		0.79 (0.29-2.16)	Segama Central	Aerial survey	Ancrenaz et al. 2010
Pongo pygmaeus morio	2007		1.76 (0.64-4.80)	Segama South West	Aerial survey	Ancrenaz et al. 2010
Pongo pygmaeus morio	2007		1.64 (0.58-4.52)	Malua	Aerial survey	Ancrenaz et al. 2010
Pongo pygmaeus morio	2007	2,580 (1,295-5,866)		USM forests, total	Aerial and ground survey	Ancrenaz et al. 2010

Threats

Surveys in 2002 and 2007 show that orangutan populations can be maintained in forests that have been lightly and sustainably logged (Ancrenaz et al. 2010). However, in heavily logged forests there was a decline in orangutan numbers (Ancrenaz et al. 2010). Nest distribution in the forests of Ulu Segama Malua indicates that orangutans leave areas undergoing active disturbance, reaching forests that are located up to 500 meters above sea level (Ancrenaz et al. 2010).

Table 3. Threats to apes in Ulu Segama-Malua

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		Oil palm plantations surround the landscape, especially along the eastern and northern borders (Ancrenaz et al. 2010, WWF 2020).	Ongoing (2020)
3. Energy production & mining		Unknown
4. Transportation & service corridors	4.1 Roads & railroads	High	5.5 roads/km of transect in overdegraded forest; 3.4 roads/km of transect in degraded forest (Ancrenaz et al. 2010).	Logging roads that are present in higher frequency in overdegraded forests (Ancrenaz et al. 2010).	Ongoing (2010)
5. Biological resource use	5.3 Logging & wood harvesting	High		Heavy logging has led to decreased orangutan abundance at the site, as well as forest fragmentation (Ancrenaz et al 2010).	Ongoing (2010)
6. Human intrusion & disturbance		Unknown
7. Natural system modifications	7.1 Fire & fire suppression	Present, but threat severity unknown		Fires to clear land, but also due to severe droughts (Ancrenaz et al. 2010).	Ongoing (2010)
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

Conventional logging practices and heavy extraction rates, coupled with high road densities and indiscriminate felling, has resulted in a mosaic of highly degraded forests bordering hilltops and isolated patches of moderate habitat; in other words, habitat in the USM landscape is very heterogeneous (Ancrenaz et al. 2010). Multiple logging cycles that began in 1957 and ended in 2007 led to drastic alterations in the original forest structure and integrity (Ancrenaz et al. 2010). Forest fragmentation has forced the orangutan population to spread into less suitable habitats (Ancrenaz et al. 2010).

Table 4. Conservation activities in Ulu Segama-Malua

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	11.7. Restore habitat corridors	Restoration in the Bukit Piton forest is intended to have a positive impact on the rest of the landscape by connecting key patches of forest (WWF 2020).	Ongoing (2020)
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 Ulu Segama-Malua

Challenge	Source
Not reported

Research activities

Documented behaviours

Table 6. Ape behaviors reported for Ulu Segama-Malua

Behavior	Source
Not reported

External links

Ulu Segama Malua - Sabah Forestry Department

Relevant datasets

A.P.E.S Portal

References

Ancrenaz, M., Ambu, L., Sunjoto, I., Ahmad, E., Manokaran, K., Meijaard, E., & Lackman, I. (2010). Recent surveys in the forests of Ulu Segama Malua, Sabah, Malaysia, show that orang-utans (P. p. morio) can be maintained in slightly logged forests. PLoS One, 5(7), e11510.
Ancrenaz, M., Gimenez, O., Ambu, L., Ancrenaz, K., Andau, P., Goossens, B., ... & Lackman-Ancrenaz, I. (2005). Aerial surveys give new estimates for orangutans in Sabah, Malaysia. PLoS Biology, 3(1), e3.
WWF .(2020). Lessons Learnt from 12 Years Restoring the Orangutan’s Habitat: the Bukit Piton Forest Reserve in the Malaysian State of Sabah. Online: https://wwf.panda.org/wwf_news/?364737/WWF-field-series-Lessons-learnt-from-restoring-the-orangutan-habitat-in-the-Malaysian-State-of-Sabah

Page completed by: A.P.E.S. Wiki team Date: 16/11/2021

Ulu Segama-Malua

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