Virachey National Park is one of the largest protected areas in Cambodia (3,325 sq km) and one of only two Cambodian ASEAN Heritage Parks. Together with adjacent protected areas in Cambodia and Laos and Vietnam, Virachey forms part of one of the largest areas of contiguous protected forest in Southeast Asia. This southern Annamites landscape is largely covered in evergreen forests and of outstanding importance for biodiversity as carbon sequestration.

Despite Virachey’s value for biodiversity, climate regulation and transboundary conservation, the park has received very limited conservation attention, with virtually none over the last decade. As its biodiversity has also been little studied, FFI collaborated with the Ministry of Environment (MoE) to conduct pioneering research in Virachey in 2018 and found that it holds the largest population in the world of the northern yellow-cheeked crested gibbon, a recently described and globally Endangered primate.

Robust information is required for future management of Virachey; we need to know what biodiversity is present and where, so that we can protect it. The 2018 survey was a strong first step in this direction and was funded by FFI’s Species Fund and the British Embassy in Cambodia. Five weeks were also spent deploying camera traps and collecting additional data across the landscape in February-March 2021, in collaboration with MoE  rangers and local communities in Ratanakiri and Stung Treng.

During the 2021 survey, Mr. Pablo Sinovas (FFI  Flagship Species Manager) and Chantha Nasak (FFI Flagship Project Officer) deployed 80 camera traps in seven areas of the park. Some of the cameras were deployed in randomized grids to allow us to estimate population densities of certain the species while others were placed to maximize inventory completeness. This represents the largest camera trapping effort undertaken in Virachey date, and having placed cameras from lowland areas to the top of the highest peaks, Pablo and Nasak are very excited to see what will reveal.

The survey also benefited from other experts from FFI and the Sam Veasna Center (SVC). These included Jeremy Holden (FFI), who recorded amphibians and reptiles and produced superb photographs and Mardy Sean (SVC) who documented birds. The FFI crocodile team also visited some of the most promising rivers to search for evidence of the Critically Endangered Siamese crocodile.

They also collected water samples for environmental DNA (eDNA) analysis. This is an efficient and non-invasive survey technique that will complement results from camera traps and field searches and should greatly improve understanding of fish species within the landscape.

The overall purpose of the survey was to develop the most complete understanding of Virachey’s biodiversity to date. This knowledge will be used to inform future management of the site, including a park zonation process that MoE wil undertake with support form FFI and other partners. Capacity building was also an important element of the survey. To this end, hands-on training was provided to MoE staff, especially park rangers, on techniques such as camera trapping, GPS use, data collection and eDNA sampling.

“There were many memorable moments during the survey. These included bathing under a waterfall encircled by a weird ring-shaped rainbow, nightly walks through the jungle in search of nocturnal animals and unwittingly playing my hand on a vine right next to a venomous (but thankfully very relaxed) Vogel’s pit viper.”(Pablo Sinovas).

Access to some areas of the park was challenging as these were covered in thick undergrowth due to the absence of an overhead canopy. This was slightly disappointing, as it appeared to be the result of past logging. Old logging roads were also found in places that were thought to be untouched. While the park has been logged in places however, the fact that no evidence of recent logging was found and that Virachey remains one of the remotest areas in Cambodia provides grounds for optimism.

“Our 2021 survey substantially enhanced understanding of Virachey’s biodiversity and on-the-ground situation, but is only a first step. We hope to undertake further surveys at different times of the year and will use this information to support zoning processes and future management of the park. More broadly, we look forward to continuing working closely with the MoE and other partners, as we scale up efforts to support the conservation of this unique protected area, its outstanding gibbon population, and its wider biodiversity.”(Pablo Sinovas).