An inventory of riverine biodiversity in monsoonal Asia: present status and conservation challenges

There are few parts of the planet where human impacts on riverine biodiversity are more apparent than in monsoonal Asia. Flow regulation, drainage-basin degradation and conversion of riverine wetlands to agriculture have been occurring for centuries, while pollution and over-harvesting have become important in recent decades. Concomitant species loss appears both ongoing and rampant. Uncertainty over rates of loss is imposed by the fact that the extremely rich biodiversity of Asian rivers has not been inventoried adequately. It is nevertheless evident that some taxa are gravely threatened. Specialist riverine birds have declined, turtles are highly endangered, and over-harvesting has severely impacted fishes--an effect that is exacerbated by pollution and flow regulation. A particular conflict that constrains biodiversity conservation is the tendency for dam construction, which damages river ecosystems, to produce tangible benefits for humans through hydropower generation and relief from floods and droughts. Resolution of such conflicts requires changes in perception: for instance, realistic economic valuations of the ecosystem goods and services provided by rivers, and promotion of flagship species as conservation icons to increase citizen awareness. Translation of awareness and knowledge to action, however, remains the essential prerequisite for societal commitment to the conservation of freshwater ecosystems.