Environmental degradation in karst areas of Cambodia: a legacy of war

Karst areas in Kampot Province, southwest Cambodia, have suffered relatively recent soil erosion and partial infilling of caves by the eroded sediment. This soil loss is most pronounced in localities that have been a focus of human activity, such as along pedestrian and vehicular access routes and in areas subject to vegetation clearing and agricultural activity, but it also occurs more widely across the hillslopes. In comparable karst environments elsewhere in Cambodia and neighbouring countries erosion is similarly evident in areas that have been subject to intensive human use, but in contrast to Kampot it is absent from the broader landscape. The soil degradation in the Kampot karst seems to require disturbance of the natural vegetation cover which stabilizes the soil cover in the other karsts, probably during the latter half of the 20th century. No major changes in deliberate land-use at the study sites that might have triggered this erosion have been identified. However, this part of Cambodia was subject to heavy aerial bombardment between 1965 and 1973, and the karst hills and their caves were a particular focus of military activity. This bombing in turn facilitated ascent of the genocidal Khmer Rouge regime which drove virtually the entire population into a subsistence rural existence, and then further armed conflict prior to that regime's overthrow, both of which are likely to have generated additional environmental damage.