Between 2006 and 2007, survey teams working this stretch of the Mekong in Kratie province counted 683 species of plants, 223 native fish, 56 amphibians and reptiles, and at least eleven kinds of large mammal. During roughly the same years, engineers were sizing a wall eighteen kilometres long to be laid across the same river a short way downstream. Cambodia has spent two decades deciding which of those two futures this reach of the Mekong should have. In October 2018, with a signature on a sub-decree, it committed 50,093 hectares of it to the first.
Sambor Wildlife Sanctuary covers 500.93 square kilometres of Sambor district, in eastern Cambodia's Kratie province, and it exists because of a single administrative act: Sub-decree No. 129, issued in October 2018 and administered by the Ministry of Environment. Neth Pheaktra, the ministry's spokesman, framed the purpose in the flat register of policy - to protect the ecosystems, maintain environmental equilibrium by conserving natural resources, and mitigate the risks of climate change and natural disaster.
He added a fourth aim that matters more than it sounds. The sanctuary was also meant, he said, to encourage the participation of local communities and stakeholders to protect, conserve, preserve and use natural resources sustainably. Protected areas drawn over inhabited river country live or die on that clause. The people inside the boundary fished and farmed here long before the boundary existed, and a line on a ministry map does not by itself change what happens under the trees.
The same batch of paperwork created a second reserve. Prek Prasab Wildlife Sanctuary, 12,770 hectares nearer the provincial capital, was established under Sub-decree No. 128 in the same month. The World Wide Fund for Nature, which had pushed for both, described the pair as supporting the most intact forests and riverine habitats in the area, with the lowest human densities anywhere nearby - which is a conservationist's way of saying that this is the last part of the region where the river country still works the way it used to.
Prek Prasab carries a particular passenger. The hog deer, Axis porcinus, was believed extinct in Cambodia until animals turned up there in 2006; roughly 84 survive. It is a small, stocky deer that ducks under obstacles rather than leaping them, and it is now hemmed in by illegal forest clearance, snaring, and hunting with dogs. Whether it lasts depends on habitat that does not stop politely at a sanctuary boundary.
This part of the Mekong is the last home of a freshwater population of Irrawaddy dolphins. In 2012 Cambodia designated a 180-kilometre stretch, running from eastern Kratie province up to the Laos border, as a limited fishing zone. As of 2024 about 105 dolphins survive along roughly 190 kilometres of river - a number that spent years being counted downward and has lately, cautiously, been counted back up.
The margins are thin, and one of them has already closed. The pool at the Laos border went quiet in 2022, when the last Irrawaddy dolphin in Laotian waters, a male 2.6 metres long and 110 kilograms in weight, was found dead. Decades of gillnets and fishing with explosives had done the work, a village at a time. Whatever else Sambor Wildlife Sanctuary protects, it sits on the bank of the species' final stronghold.
The sanctuary shares a name with a dam. The proposed Sambor Dam, rated at 2,600 megawatts, would run 18,002 metres across the Mekong at Prek Kampi district in Kratie and stand 56 metres high - the largest hydropower scheme ever seriously advanced for the lower mainstream. A Mekong River Commission study as long ago as 1994 warned that it would block fish migration in both directions, in a country where the Tonle Sap fishery supplies around 60 percent of annual landings. It would also sit directly on the dolphins.
In March 2020 the government suspended mainstream Mekong hydropower until 2030. For now the operative fact on this reach of river is a boundary, not a barrage: 50,093 hectares of forest and flooded riverbank, and a dam that remains a drawing. Which of the two turns out to be the permanent one has not been settled.
Sambor Wildlife Sanctuary lies at 13.2231 N, 106.0174 E, in Sambor district of Kratie province, north-eastern Cambodia, east of the Mekong mainstream and roughly midway between Kratie and Stung Treng towns. From the air it reads as an unbroken block of green against the cleared and cultivated land beyond its boundary - the contrast at the edge is often the clearest way to find it. The Mekong itself lies a short distance west and is the primary navigation reference for the whole reach, running wide, braided and island-strewn here. Recommended viewing altitude 3,000-6,000 ft AGL for forest canopy texture and the boundary contrast; higher, around 10,000 ft, to take in the sanctuary, the river, and the sister reserve at Prek Prasab downstream in one frame. Nearest operating airport is Techo International at Phnom Penh (VDTI), roughly 280 km south-west; the Kratie and Stung Treng airstrips are abandoned. Best visibility is December to February. Expect heavy agricultural-burning haze February to April and afternoon convection with towering cumulus from May to October.