Tonle Sap

The Tonle Sap Biosphere Reserve is a UNESCO biosphere reserve around Southeast Asia's largest freshwater lake. It was nominated in 1997 and established by Royal Decree in 2001^[1]. Its three core areas cover about 42,300 hectares^[1].

The seasonal wetlands support rare and endangered plants, reptiles, mammals and birds, and are a breeding area for fish from the lake and the Mekong^[1]. Siamese and saltwater crocodiles once lived together in the lake^[1].

Seasonally flooded forest fringes the lake, and parts of it have been cleared for farming^[1].

The Tonle Sap River links the lake to the Mekong. From mid-June to late October Mekong flooding reverses the river's flow back toward the lake, and from November to June the lake drains into the Mekong^[1].

The lake grows from about 2,500 square kilometres to more than 16,000 square kilometres during the rainy season, which runs from mid-June to late October^[1].

Water-dwelling communities live on the lake, and some residents of the core areas may fish under Cambodian fishery law^[1]. Many people around the lake are very poor and depend on it for their livelihoods^[1].

The reserve was nominated in 1997 and established by Royal Decree in 2001 to serve conservation, development and logistic functions^[1]. Since 2003 the Asian Development Bank has funded the reserve's secretariat^[1].

The core areas are Prek Toal in Battambang Province, Boeng Tonle Chhmar, a Ramsar site, and Stoeng Sen, both in Kampong Thom^[1].

Kampong Chhnang, about 15 km away, is the nearest city on the lake's southern shore.

Threats include illegal fishing and poaching, flooded-forest clearing for farming, irrigation channels that reduce water in fishing areas, pesticide runoff and falling catches of large fish^[1].