Ecosystems in the Greater Mekong: past trends, current status, possible futures

The Greater Mekong Subregion (GMS: Myanmar, Thailand, Cambodia, Laos, Vietnam, and Yunnan and Guangxi in China) is undergoing unprecedented changes. Many of these are positive, reflecting political stabilization and economic growth following decades of poverty and conflict. But the rate and type of development is also threatening critical natural resources, particularly native forests, the Mekong River and its tributaries, and many wild plant and animal species. The GMS faces a critical choice: it can either continue with unsustainable development and see many of its unique natural resources disappear forever or switch policies and choose a more sustainable path into the future. This report gives an overview of what is happening, and provides key recommendations for how natural resource management can be made more sustainable.

The core of the report is a series of maps, developed by WWF, describing the historical trends, current status and future projections of forests in the GMS excluding China. Future projections for the period 2009 to 2030 contrast two scenarios; an unsustainable growth scenario, which assumes deforestation rates between 2002 and 2009 continue, and a green economy scenario, which assumes a 50 per cent reduction in the annual deforestation rate relative to the unsustainable growth scenario, and no further losses in key biodiversity areas. …

Recent changes: between 1973 and 2009, the GMS (excluding China) lost just under a third of its forest cover (22 per cent in Cambodia, 24 per cent in Laos and Myanmar, and 43 per cent in Thailand and Vietnam) according to WWF’s analysis. In official statistics for tree cover across the whole of the GMS, these losses are partially masked by large-scale plantation establishment in Vietnam and China, where there has been a gradual replacement of natural forests by monoculture plantations. Myanmar accounted for over 30 per cent of total forest loss in the GMS over this period. At the same time, forests became far more fragmented: large areas of intact forest (core areas) declined from over 70 per cent of the total in 1973 to only about 20 per cent in 2009.

 Projections: by 2030, under the unsustainable growth scenario, another 34 per cent of GMS forests outside China would be lost and increasingly fragmented, with only 14 per cent of remaining forest consisting of core areas capable of sustaining viable populations of wildlife requiring contiguous forest habitat. Conversely, under the green economy scenario, core forest patches extant in 2009 would remain intact, although 17 per cent of GMS forests would still be converted to other uses. Regardless of scenario, deforestation “hotspots” include the margins of large forest blocks remaining in Cambodia, Laos and Myanmar. The model suggests that deforestation in Vietnam will be distributed in small pockets across the country, although the greatest losses are anticipated in parts of the Central Highlands and northern provinces. This report also contains a map, constructed from historical patterns, of likelihood of conversion of any particular forest block, based on the distances from roads, non-forest areas, water, cities, and new and planned mines, along with elevation and slope. …

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