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The Mekong
The Mekong River is one of the great river systems of the world. Rising in the Tibetan Plateau and disgorging into the South China Sea some 4,800 kilometres later, it is ranked as the twelfth longest of the world’s rivers, draining 795,000 km2 of six countries – China, Myanmar, Thailand, Lao PDR, Cambodia and Vietnam. In terms of annual discharge it ranks eighth highest in the world at some 475,000 million cubic metres. The seasonal variation in water level, and the range of wetland habitats inundated is the source of the productivity of the system. Wet season river levels are up to eight to ten metres higher than dry season ones, creating a rich and extensive series of wetlands in the four countries of the Lower Mekong Basin prior to reaching the four million hectare delta.

The biodiversity of the Mekong River Basin is immense, and of truly exceptional significance to international biodiversity conservation even in comparison with other parts of tropical Asia. The river and its numerous tributaries, backwaters, lakes, and swamps supports many unique ecosystems and a wide array of globally-threatened species such as the Irrawaddy Dolphin, Siamese Crocodile, Giant Catfish and birds such as the Giant Ibis and Sarus Crane. The diversity of the river fauna itself is surpassed only by that of the Amazon and the Congo, with over 1,300 species of fish inhabiting the main channels, tributaries, and associated wetlands.

This biodiversity is fundamental to the viability of natural resource-based rural livelihoods of a population of 55 million people living in the Lower Mekong Basin - equivalent to more than 90 per cent of the population of the entire Mekong Basin, and about one third of the total population of Cambodia, Lao PDR, Thailand and Vietnam combined. Rural livelihoods are founded on the integrated use of a wide range of natural resources, adapting to the seasonal changes of flooding and recession. The significance of this diversity of economic activity and therefore the importance of wetland ecosystems has often been overlooked in national development strategies. Increasingly, evidence indicates that wetland resources are of particular importance to poorer groups, with significant implications for poverty reduction strategies, food security planning and rural to urban migration and employment. These will become even more significant if wetland resources are reduced.

Despite the rapid economic advances made over the last decade, Cambodia, Lao PDR, and Vietnam are classified as low income countries with a per capita GDP of US$280-360 (compared with an East Asia/Pacific region average GDP of US$990). Thailand is a middle income country with a per capita GDP of US$2,200, but rural households in the Mekong basin have a per capita income of US$800. With the exception of Thailand and to a lesser extent Vietnam, the national economies of the Lower Mekong states are based primarily on agriculture and natural resources. Over three-quarters of each of the populations of Cambodia, Lao PDR, Thailand, and Vietnam are living outside of towns and cities with livelihoods reliant almost entirely on subsistence farming, fisheries, wildlife, forest products and plant resource utilisation. Wetland biodiversity also makes a significant contribution to national economic indicators such as income, employment and foreign exchange.

Such high levels of human population and usage have led to increasing unplanned development pressures within the basin, causing many direct threats to most of the important ecosystems and endangered species for which the region is renowned. This poses a significant threat to biodiversity and environmental sustainability, and thereby to the livelihoods of the Mekong peoples. Only 1.3 per cent of the once biodiversity-rich Mekong Delta now remains in a semi-natural condition and the few remaining wetland species are wholly reliant on these remnant patches. Similarly in Esarn, a Thai portion of the Lower Mekong Basin, infrastructure development has reduced natural wetlands to a small fraction of their original distribution. The peak annual inundation of Lake Tonle Sap has been reduced by changes to the river peak flows, threatening the largest large waterbird-breeding colony in Asia. Degradation of wetland habitats and hydrological regimes poses perhaps the greatest threat to the viability of one of the most important freshwater fisheries in the world, and the most important source of animal protein in rural diets. Widespread hunting and over-fishing, inflated by a massive illicit wildlife trade, has brought many species to the brink of imminent extinction, and development of river infrastructure is believed to have caused the extinction of a number of endemic fish species.

The Mekong Wetlands Biodiversity and Sustainable Use Programme has been developed to address the critical state of the Mekong. The programme is a complex integration of sectors designed to address the economic, environmental and social aspects of the region.