The fish biodiversity of the entire Mekong River system rivals that of the Amazon River, but within an overall watershed some 6 times smaller.
These 3 tributaries support some of the most intact riverine bird gatyherings known in Southeast Asia. The Mekong wagtail, a species new to science and endemic to the lower Mekong Basin, was first described in 2001 along stretches of these rivers in the Dry Forests.
The Giant Carp - the largest carp species in the world - is thought to rely on tributaries of the Mekong River in the Dry Forests as important spawning grounds. These fish can grow up to 3m in length, weigh well over 100kg and are very long-lived. Adults are becoming increasingly rare - possibly through the over-fishing of juveniles.
The threatened irrawaddy dolphin is found in stretches of the Mekong River within the Dry Forests - sadly probably less than 100 remain in the Mekong, and so unless a concerted effort is made to conserve them, the chance of local extinction is high.