pretty douc
 

Primates



Gibbons

We are currently conducting a preliminary research on the behavioural ecology and density of gibbons in Nakai-Nam Theun. Thank you to our Sponsors for supporting this research!

gibbons

Listen to a duet call of N. siki, recorded straight from the field!

The current taxonomic status and distribution range limit of the population of gibbons occurring in NNT remains uncertain. It may hold both the Northern and Southern white?cheeked gibbon, one of these two, or a hybrid population. Taxonomic status of gibbons in the area will therefore be addressed through records of their calls, which can be used for species identification. We will conduct a behavioural ecological study on the species: after determining number of groups at our research site, using the triangulation method, we will record data on the feeding ecology, activity budget, home range and habitat use of one focal group. The preliminary data of this research will be conducted by Mr. Chanthalaphone Nanthavong, Lao MSc student at Suranaree University of Technology in Thailand and Dr. Camille N.Z. Coudrat.

About white-cheeked gibbons

White-cheeked gibbons (Nomascus leucogenys/N. siki) are little known in terms of their distribution and taxonomic status and their behavioural ecology. Surveys in some areas have allowed re-assessment of their global conservation status, however considerable gaps in our knowledge remain. Research on these taxa is urgently needed. Previously considered as a single species under N. leucogenys, the latter was re-evaluated as two distinct species, namely the Northern white-cheeked gibbon (N. leucogenys) and the Southern white-cheeked gibbon (N. siki). Both species? distribution range limits remain unclear.

Nomascus leucogenys is native to China, Vietnam and Laos but is believed to be virtually extinct from China (Bleich et al., 2008; Fan Pengfei and Hou Sheng 2009). In Vietnam, of the few remaining sites where the species has not yet been extirpated from deforestation and hunting, Pu Mat National Park was recently identified as the main National stronghold of the species with an estimated 130 groups (Luu Tuong Bach & Rawson 2011). Nomascus siki is endemic to Laos and Vietnam. In Vietnam, remaining populations are essentially small and isolated; the two largest populations are found in Phong Nha-Ke Bang National Park (at least 50 groups) and Bac Huong Hoa Nature Reserve (at least 23 groups) (Rawson et al., 2011). The world?s largest population of both species are likely found in Laos, however their distribution and abundance are poorly known in the country.

Across their range, both species are under severe threat from illegal hunting, especially so in Vietnam where gibbons are particularly targeted for pet trade and traditional medicine in addition to hunting for local consumption (Rawson et al., 2012). In Laos, gibbon populations are in better condition inhabiting larger little encroached forest blocks (MAF, 2011). Local taboos in some areas (e.g. northern Nam Kading NPA, where N. leucogenys occurs; Ruppell, pers. comm., 2012) have prevented gibbon hunting; however these cultural beliefs tend to disappear over generations. Both species are protected by the Lao Wildlife Law under the Prohibited category of the hunting regulation (NA, 2007); it is therefore illegal to hunt at any time and anywhere these species. Nonetheless, illegal hunting by Lao villagers for local consumption and trade with Vietnamese and by Vietnamese hunters, are the main threats to gibbons in Laos, especially near the Vietnamese border (Duckworth, 2008; MAF, 2011).

In Laos, it has been suggested that the Nam Kading (river) is the geographical barrier between the two species, which would suggest both N. leucogenys and N. siki present in Nakai-Nam Theun NPA (Van Ngoc Thinh et al., 2010) or possibly a hybridization zone given that the river within Nakai-Nam Theun NPA becomes narrow and is easily crossed.

Their ecology is virtually unknown, with a single published study on N. leucogenys (Hu et al., 1989) and none on N. siki.  Both species are among the most common gibbon species found in zoological collections (ISIS, 2012); long-term ecological research will provide invaluable information to improve captive management.

Nakai Nam Theun NPA represents the ideal research site to establish a long-term conservation and research project on Nomascus leucogenys/siki. Surveys in the NPA in 2011-2012, during which time 10 sites were visited, revealed a healthy population of gibbons (Coudrat, 2012). However, human encroachment is evident in the area, including illegal hunting and logging. A long-term ecological research in the area will aid with their protection.

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Doucs

The Endangered red-shanked douc is a charismatic Asian colobine endemic to Vietnam, Cambodia and Laos. Its largest population is found in central-eastern Laos, yet, it has never been quantified. We reviewed the distribution and status of doucs in Laos and revealed that its world's largest population and best hope its global and long-term conservation is in Laos. Nakai?Nam Theun and Hin Namno National Protected Areas in Laos hold the largest populations of P. nemaeus, but the species faces great threats from hunting in both areas. Management should focus on control of illegal hunting and long-term research and conservation to maintain healthy populations.

To learn more about doucs in Laos, read our Publication co-authored with colleagues.

We conducted line transect surveys in Nakai-Nam Theun National Protected Area (NPA) in 2011-2012 and recorded sightings of Pygathrix nemaeus. We used distance sampling method combined with a habitat suitability model computed in MaxEnt to estimate their group density and group abundance in the area. Our analysis yielded a density of 2.8 (±1.9 - 4.1) groups per km˛ and ca. 4420 groups within the predicted c. 1600 km˛ of suitable habitat in Nakai-Nam Theun NPA. To date these figures represent the only available for the country. This large population is under high threat from illegal hunting and the species does not receive any specific conservation action in Laos. To avoid the Lao population undergoing the same dramatic declines shown by the species in Vietnam and secure the global survival of the species, conservation projects need to target the population in Nakai-Nam Theun NPA. A long-term conservation and research project in this key biodiversity area will benefit other threatened and unique co-existing species.

To learn more, read our Publication

We are currently conducting a preliminary research on the behavioural ecology of the red-shanked douc at our research site, thanks to the generous sponsoring of the Mohamed Bin Zayed Species Conservation Fund. Please visit our project's profile published on their website.

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Macaques

We investigated the niche separation of the four macaque species (Macaca arctoides, M. assamensis, M. leonina, M. mulatta) occurring within Nakai-Nam Theun National Protected Area, using the environmental niche modelling software MaxEnt. The respective suitable habitat predicted for each species reveals niche segregation between the four species with a gradual geographical distribution following an environmental gradient of, notably, temperature, precipitation, elevation and slope within the study area. This means that the four species seem adapted to different ecological conditions within the area. This information has implications for future research on these species and for their management and conservation.

To learn more, read our Publication, co-authored with colleague