The mountains of Asia, including the Himalayas, are facing accelerating threats from a rapid rise in roads, settlements, overgrazing and deforestation experts are warning in a new report.

There is concern that the region’s water supplies, fed by glaciers and the monsoons and vital for around half the world’s population, may be harmed alongside the area’s abundant and rich wildlife.

The new report points to a critical gap in the security of the water to billions of people in Asia and the crucial role of sound environmental management for sustainable development.

It claims that unchecked and piecemeal development are likely to increase rates of forest loss triggering increased levels of erosion, pollution and other potentially harmful effects.

Conversion of pristine areas into farm and grazing land is aggravating the situation, the report adds.

Indeed satellite images reveal that deforestation and unsustainable land use practices may explain why the region’s rivers now have the largest sediment loads in the world and why dissolved nutrients in the water are increasing more than in any other region.

This is one of the primary causes for the increasing human drought and flood-related disasters in the region, including the latest floods and resultant high number of casualties in China and India.

By combining a range of local studies with satellite images from 1960 up to today, the scientists have been able to reveal for the first time the scale of land-use changes in the region.

Klaus Toepfer, executive director of the United Nations Environment Programme (UNEP), said: "The Millennium Development Goals covering poverty eradication and the better supply of sufficient, safe, drinking water up to reversing the spread of disease cannot be met without economic growth. But this needs to be carried out in a way that conserves the life support systems and the ecosystem services they provide. Otherwise it cannot be sustainable for current or future generations.

"Mountain areas are especially important and particularly vulnerable. These are the water towers of the world and often home to unique wildlife species upon which local people depend for food, medicines and other important materials. They have often been saved from uncontrolled development by their remoteness. But modern engineering methods mean this is no longer the case."

Researchers claim some countries including China and Nepal are now acting to develop parks and protected areas aimed at conserving the Asian region’s water supplies and wildlife.

However, the scientists warn that far more effort is needed to extend protection right across the region in both lowland and mountain areas if the impacts are to be minimized.

Christian Nellemann of UNEP’s GRID centre in Norway, added: "Local indigenous people often see their vital resources exploited, while they benefit little from the development. Further down river, impoverished people are also those that are the most severely exposed to the risk of floods and seasonal drought, as they often have to settle in flood-risk areas. We have to speed up conservation efforts in these watersheds to ensure safe water resources."

The findings have come from a new report entitled 'The Fall of Water' launched on Monday by The World Conservation Union (IUCN) and UNEP.