Summary

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Northern yellow‐cheeked gibbons (Nomascus annamensis) are present in Song Thanh Nature Reserve.
It has been estimated that 443 (95% CI, 278–707) groups occur in the site.
The gibbon population trend is unknown.
The site has a total size of 765.93 km².
Key threats to gibbons are illegal logging, agricultural expansion, and hunting.
Conservation activities are not documented.

Site characteristics

Song Thanh Nature Reserve is located in Quang Nam Province, central Vietnam. The site is bordered by Highway 14D to the north, Highway AH17 to the south, Lao PDR to the west, and the Thanh river to the east (Van Tran & Tien Vu 2020). The forest cover is about 90% of the total area of the reserve. The topography of the area is complex, with altitudes ranging from 80 to 2,032 m above sea level (Van Tran & Tien Vu 2020). The reserve is a Key Biodiversity Area. Field surveys have documented 73 mammal species, 177 bird species, 118 reptile and amphibian species and 671 plant species at the site (USAID 2018). Species records include three mammals found only in this landscape; Owston’s civet, Chrotogale owstoni, the Annamite striped rabbit, Nesolagus timminsi, and the large-antlered muntjac, Muntiacus vuquangensis (USAID).

Table 1. Basic site information for Song Thanh Nature Reserve

Species	Nomascus annamensis
Area	765.93 km²
Coordinates	Lat: 15.546228 , Lon: 107.482601
Type of site	Protected area (Nature Reserve)
Habitat types	Subtropical/tropical moist lowland forest, Subtropical/tropical heavily degraded former forest
Type of governance

Types of sites Governance types Habitat types

Ape status

A 2019 survey determined a total suitable habitat for gibbons of 302.32 sq.km (Van Tran & Tien Vu 2020). The survey team detected 36 gibbon groups through field surveys and estimated 443 (95% CI, 278–707) gibbon groups in Song Thanh Nature Reserve. The results indicate that the gibbon population in Song Thanh Nature Reserve is the largest known population of N. annamensis in Vietnam (Van Tran & Tien Vu 2020). Furthermore, it was estimated that the total area of suitable habitat for the northern yellow‐cheeked gibbon was 302.32 km2, or 39.47% of the reserve's area (Van Tran & Tien Vu 2020).

Table 2. Ape population estimates reported for Song Thanh Nature Reserve

Species	Year	Total number groups (95% CI)	Density [groups/km²] (95% CI)	Total number indiv. (95% CI)	Area	Method	Source	Comments	A.P.E.S. database ID
Nomascus annamensis	2019	1.46 group/km2 (95% CI, 0.92-2.34)	443 (95% CI, 278-707)		Song Thanh Nature Reserve	Fixed point triangulation	Van Tran & Tien Vu 2020

Sampling methods Analytical frameworks

Threats

The density distribution of gibbons at the site has been shown to be influenced by the distance to villages (Van Tran & Tien Vu 2020). Local people depend heavily on forest resources. Activities such as illegal logging, wildlife trapping, shifting cultivation and wood collection are the main threats to wildlife in the reserve; especially hunting and trade of wildlife (Hoang et al. 2010).

Table 3. Threats to apes reported for Song Thanh Nature Reserve

Category	Specific threats	Threat level	Description	Year of threat
5 Biological resource use	5.1 Hunting & collecting terrestrial animals	High (more than 70% of population affected)	Hunting with snares (other animals are targeted) (Hoang et al. 2010, KBA 2020).	2010-Ongoing (2020)
4 Transportation & service corridors	4.1 Roads & railroads	Low (up to 30% of population affected)	Construction and upgrade of roads in the area (Hoang et al. 2010, KBA 2020).	Ongoing (2010)
5 Biological resource use	5.3 Logging & wood harvesting	Present (unknown severity)		Ongoing (2018)
1 Residential & commercial development	1.1 Residential areas	Present (unknown severity)	The density distribution of gibbons at the site has been shown to be influenced by the distance to villages (Van Tran & Tien Vu 2020).	Ongoing (2020)
2 Agriculture & aquaculture	2.1 Annual & perennial non-timber crops	Medium (30-70% of population affected)	Shifting agriculture; slow but significant deterioration (KBA 2020).	Ongoing (2020)

Threats

Conservation activities

Challenges

Table 5. Challenges reported for Song Thanh Nature Reserve

Challenges	Specific challenges	Source	Year(s)
	Not reported

Challenges

Enablers

Table 6. Enablers reported for Song Thanh Nature Reserve

Enablers	Specific enablers	Source	Year(s)
1 Site management
2 Resources and capacity
3 Engaged community
4 Institutional support
5 Ecological context
6 Safety and stability

Enablers

Research activities

Documented behaviours

Table 7. Behaviours documented for Song Thanh Nature Reserve

Category	Behavior	Observation type	Prevalence	Observation dates	Source	Habituation	Species	Comment
	Not reported

Behaviours

Exposure to climate change impacts

External links

References

Tran, D. V., & Vu, T. T. (2020). Combining species distribution modeling and distance sampling to assess wildlife population size: A case study with the northern yellow‐cheeked gibbon (Nomascus annamensis). American Journal of Primatology, 82(9), e23169.

USAID (2018). PA FACT SHEET SONG THANH NATURE RESERVE. Online: https://pdf.usaid.gov/pdf_docs/PA00TSDW.pdf

Key Biodiversity Areas Partnership (2020). Key Biodiversity Areas factsheet: Song Thanh. Extracted from the World Database of Key Biodiversity Areas. Developed by the Key Biodiversity Areas Partnership: BirdLife International, IUCN, American Bird Conservancy, Amphibian Survival Alliance, Conservation International, Critical Ecosystem Partnership Fund, Global Environment Facility, Global Wildlife Conservation, NatureServe, Rainforest Trust, Royal Society for the Protection of Birds, World Wildlife Fund and Wildlife Conservation Society. Downloaded from http://www.keybiodiversityareas.org/ on 14/12/2021.

Hoang, C., Trang, L., & Tinh, N. (2010). Technical Report on Wildlife hunting and Trading in Song Thanh Nature Reserve, Quang Nam Province, Vietnam. Interim report for phase 1 MacArthur foundation, Education for Nature, Ha Noi, Vietnam.

Page created by: APES Atlas Team Date: 2021-12-29