Dakrong Nature Reserve

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Summary

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• Northern yellow-cheeked crested gibbons (Nomascus annamensis) are present in Dakrong Nature Reserve.
• The population size is unknown.
• The gibbon population trend is unknown.
• The site has a total size of 376.18 km².
• Key threats to gibbons are illegal logging and exploitation of non-timber forest products.
• Conservation activities are not documented.

Site characteristics

Located in Quang Tri Province, in the center part of the Annamite Mountain Range, Vietnam, the Dakrong Nature Reserve was established in 2001(Vu & Doherty 2021). Approximately half the area is covered by rich and medium evergreen forest; the rest is covered by poor, regrowth forest, plantations, or bare land. The terrain of the reserve consists of low and medium hills, with the highest peak reaching 1410 m above sea level (Vu & Doherty 2021).

Table 1. Basic site information for Dakrong Nature Reserve

Species	Nomascus annamensis
Area	376.18 km²
Coordinates	Lat: 16.625414 , Lon: 106.893379
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

The northern yellow-cheeked crested gibbon only occurs in the Central Annamite mountain range along the borders of Vietnam and Laos, and Vietnam and Cambodia. No complete survey for the species has been conducted (Vu & Doherty 2021). A survey was conducted in the reserve in 2019 using passive acoustic monitoring. Gibbon calls were detected in 39 out of 95 recording sites (Vu & Doherty 2021). Assuming a 600 m detection distance, the model-averaged occurrence probability for the nature reserve was 0.44 (SE=0.06). The area of rich and medium evergreen forests within a km of the recording posts was the most important predictor of occurrence (positively correlated). Detection probability was estimated to be 0.52 (SE=0.04) per day (Vu & Doherty 2021).

Table 2. Ape population estimates reported for Dakrong 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				Dakrong Nature Reserve	Passive acoustic monitoring	Vu & Doherty 2021

Sampling methods Analytical frameworks

Threats

Most hunters active in the region are thought to come from other provinces, more than 100 km away from the reserve. Similar to other studies, a 2021 study showed a higher occupancy of gibbons in high vs low quality forest (Vu & Doherty 2021). Generally, northern yellow‐cheeked gibbon populations have dramatically decreased in Vietnam due to hunting, habitat loss, and the wildlife trade. The site has been selectively logged in the past, and timber and NTFP exploitation still occurs in the reserve. In addition, local communities live in villages near the nature reserve boundary (Vu & Doherty 2021).

Table 3. Threats to apes reported for Dakrong Nature Reserve

Category	Specific threats	Threat level	Description	Year of threat
5 Biological resource use	5.1 Hunting & collecting terrestrial animals	Present (unknown severity)	Signs of wildlife hunting and trappings are recorded in the nature reserve (Vu & Doherty 2021).	Ongoing (2021)
5 Biological resource use	5.2 Gathering terrestrial plants	Present (unknown severity)	Illegal exploitation of non-timber forest products (Vu & Doherty 2021).	Ongoing (2021)
5 Biological resource use	5.3 Logging & wood harvesting	Present (unknown severity)	Illegal timber exploitation, in the past and ongoing (Vu & Doherty 2021).	Ongoing (2021)
9 Pollution	9.2 Industrial & military effluents	Medium (30-70% of population affected)	Forest cover has been reduced by the spraying of chemical defoliants during the Second Indochina War (BirdLife International 2022).	1955-1975

Threats

Challenges

Table 5. Challenges reported for Dakrong Nature Reserve

Challenges	Specific challenges	Source	Year(s)
	Not reported

Challenges

Enablers

Table 6. Enablers reported for Dakrong 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

Documented behaviours

Table 7. Behaviours documented for Dakrong Nature Reserve

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

Behaviours

References

BirdLife International. (2022). Important Bird Areas factsheet: Dakrong. Retrieved from http://www.birdlife.org on 31 January 2022.

Vu, T. T., & Doherty, P. F. (2021). Using bioacoustics to monitor gibbons. Biodiversity and Conservation, 30(4), 1189-1198. doi:10.1007/s10531-021-02139-1

Page created by: APES Atlas Team Date: 2022-01-28