In the satellite image of the Mekong basin's forest cover, it resembles a piece of fine cloth that is beginning to come apart.
A new WWF report reveals that between 1973 and 2009, five countries of the Greater Mekong Sub-region (GMS) lost just under one-third of their forest cover.
Individually, in 36 years, Cambodia lost 22 per cent of its 1973 forest cover, Laos and Myanmar lost 24 per cent, and Thailand and Vietnam lost 43 per cent.
Forest connectivity - crucial to ensure survival of wildlife populations - also suffered enormously.
"Large connected areas of core forest… declined significantly across the region, from over 70 per cent in 1973 to about 20 per cent in 2009," says the report by the conservation non-government organisation.
"Further rapid loss is expected if current deforestation rates persist," it warns.
Avoiding this loss - which would decimate the region's natural capital - is possible if policymakers take a regional, long- term approach, that is, "landscape level" planning over wide geographic areas over the long term.
Policymakers are often caught in a pattern of responding to immediate issues and problems, and have difficulty stepping back and designing solutions at larger scales with longer timeframes, said Dr Peter Cutter, landscape conservation manager of WWF's Greater Mekong programme.
The Mekong and its associated rivers provide resources and livelihood for some 70 million people. It is the world's largest and most productive inland fishery, with 35 per cent of the species migratory. Of the 13 distinct systems in the basin, 11 have connectivity, but many are likely to lose it soon.
A series of dams planned for the Mekong - starting with the controversial Xayaburi dam in Laos that has soured ties between Laos, Cambodia and Vietnam, which share the river's waters - will break up connectivity, blocking the paths of migratory species.
The basin is also one of the most biologically diverse places on the planet, with new species being discovered on a regular basis: 1,710 between 1997 and 2011. Yet several species, like the Javan rhino, have gone extinct, and many are in serious or terminal decline.
The challenges are wide and disparate. Ecosystem change across the vast region is driven in different places by different interlinked factors combining to change land use. Forests are eaten away by urbanisation, agriculture, industry, highways, dams and mines.
Fast-growing economies in and around the region, especially China, are increasingly sourcing timber, palm oil, rubber, wood pulp, minerals and other natural resources here, "transforming the GMS from subsistence to commercial, export-orientated agriculture", the report says.
While legally protected areas had increased since the 1970s, many existed only in name, Dr Cutter noted in a statement on the report. "Even relatively secure protected areas are under intense pressure from poaching and timber theft, while others have been reduced in size by governments eager to cash in on land concessions to mining companies or plantation owners."
He adds: "The Greater Mekong is at a crossroads. One path leads to further declines in biodiversity and livelihoods, but if natural resources are managed responsibly, this region can pursue a course that will secure a healthy and prosperous future for its people."
In the business-as-usual "unsustainable growth" scenario, in the next 20 years, another 34 per cent of forest cover will be lost and increasingly fragmented, with only 14 per cent of remaining forest capable of sustaining viable populations of wildlife.
In the "green economy" scenario, there would be a 50 per cent cut in annual deforestation. But it requires better governance, transparency, community involvement in decision-making, and enforcement of the rule of law in environment and wildlife crime.
