Freshwater health index assessment of the Tonle Sap basin

摘要: The Tonle Sap Lake and River basin cover almost half of Cambodia’s land surface, contain one of the world’s largest inland fisheries and are rich in biodiversity. While the Tonle Sap Lake and its relationship to the Mekong River is well studied, until now the freshwater health of the basin has been overlooked. We used a freshwater health index to diagnose the basin’s condition as of December 2021. Ecosystem vitality and ecosystem services scored 41 and 75, respectively, out of a possible 100, while governance and stakeholders scored 58. Consistent with freshwater health assessments in other parts of the Mekong, the Tonle Sap basin provides valuable ecosystem services. But components of its underpinning biophysical system are degraded. The basin’s highly fragmented river network and high numbers of threatened species (particularly fish) threaten the future of the lake’s vital fishery, which received a moderate score