When WCS first began working in the Prek Toal flooded forest and the wider Tonle Sap floodplain, illegal hunting was the main challenge faced by wildlife at both sites. Conservation activities have successfully reduced these threats, but greater challenges are now emerging in the shape of climate change, large-scale infrastructure development and land grabbing.
Conservation activities in the Prek Toal flooded forest initially targeted the collection of chicks and eggs at nest sites. These challenges have now evolved, with growing evidence that the aquatic resources of the Tonle Sap Lake may be threatened by habitat loss and over harvesting. The development of dams on the Mekong mainstream and the effects of climate change are likely to result in changes in the flood patterns and sediment load of the Tonle Sap, with potentially negative impacts on the productivity of the fisheries, the flooded forest and the bird species that nest there. From a human livelihoods point of view, reduced fish stocks are of great concern, with declines in both the average size of fish caught in the lake and a decline in the catch per unit effort for most species, with many fishers across the lake reported decreases in fish catch.
2005 to 2007, and losses have continued at a high rate since then. Most of the loss is due to a recent wave of agricultural conversion by companies and businessmen. Earth dams of 100-1000 ha are built to capture the floodwaters in the rainy season and then irrigate surrounding rice fields in the dry season. This commercial dry season rice is quite different from the small-scale rice farming ('recession rice') practised by local communities. Local community members are mostly excluded from the new, large-scale schemes and are denied access to land that they have used for generations.