Uncovering Asia's river of the lost species

AT A rate science can barely keep pace with, the treasures of Greater Mekong are redefining our perception of the animal kingdom.

Deep within its unexplored jungles and fertile floodplains, and beneath its mangroves and winding waters, scientists have found more than a thousand new species in the area of south-east Asia over the last decade, the equivalent of two discoveries a week.

From bright green pitvipers, striped rabbits and a rat thought to have become extinct 11 million years ago, to bright pink millipedes laced with cyanide and spiders the size of a dinner plate, the vast region abounds with life that until recently was unknown to man.

The area spans no fewer than six separate nations, and war, diplomatic tensions and its sheer remoteness have meant its 600,000 sq km expanse has long been off limits to those in search of the natural world's wonders.

The vast majority of the species were found in the rainforests and wetlands along the Mekong, the world's 12th longest river, which flows through Cambodia, Laos, Burma, Thailand, Vietnam and the southern Chinese province of Yunnan.

Others were located hiding in more prosaic and disturbing habitats: in the rafters of a restaurant or as carcases on sale at a stall in a local meat market.

The project to uncover the secrets of Mekong is the brainchild of the World Wildlife Fund (WWF), which described it as a "biological treasure trove".

In a report released yesterday, entitled First Contact in the Greater Mekong, the WWF said that between 1997 and 2007, at least 1,068 species were discovered in the area. They include 519 plants, 279 fish, 88 frogs, 88 spiders, 46 lizards, 22 snakes, 15 mammals, four birds, four turtles, two salamanders and a toad. In addition, there are perhaps thousands of new invertebrate species.

For those scientists who have helped to add to nature's knowledge bank, the discoveries in Mekong represent the ultimate professional achievements.

Dr Thomas Ziegler, the curator of Cologne Zoo, where endangered species from Vietnam are bred, said his work in Mekong made him think of the father of natural science.

"This region is like what I read about as a child in the stories of Charles Darwin," he said.

"It is a great feeling being in an unexplored area and to document its biodiversity for the first time … both enigmatic and beautiful."

As the discoveries increased, the true significance of Greater Mekong became apparent to people like Dr Ziegler. The Mekong itself is now regarded as the richest waterway on the planet for biodiversity, and so extraordinarily high is the plant diversity that experts believe that the complex merging of floras in the highlands of the area has no parallel in any other part of the world.

Certain species found in and around the Mekong stand out. The Laotian rock rat, for instance, was thought to be extinct until the nocturnal rodent was found alive and well in remote forests in Laos. Researchers say it is the sole survivor of an ancient group of rodents understood to have died out 11 million years ago.

The region has provided scientists with among the last uncharted territories in the world. After 50 years in which only one new large mammal species had emerged worldwide, three new hoofed mammals were identified in the same region of Vietnam within four years.

Amongst these was the discovery of the saola, a bovine dwelling in the evergreen forests of the Annamite Mountains of Laos and Vietnam, which received widespread international interest and triggered a series of scientifically explosive expeditions into the jungles of the area.

For Stuart Chapman, director of the WWF's Great Mekong Programme, such finds have widened the boundaries of science.

He said: "It doesn't get any better than this. We thought discoveries of this scale were confined to the history books. This reaffirms the Greater Mekong's place on the world map of conservation priorities."

Yet for all the joy involved in encountering new species, researchers are increasingly concerned about their long-term survival in the Greater Mekong.

The region is ranked as one of the top five most threatened biodiversity hotspots in the world by Conservation International (CI), and the threats to the flora and fauna are numerous.

Now that peace and political stability have arrived, the Mekong countries are gradually shifting from subsistence farming to more diversified economies, and to more open, market-based systems, making the region a new frontier of Asian economic growth.

Nicole Frisina, communications officer for the WWF's Greater Mekong Programme, explained: "Population growth and economic development are putting considerable pressure on forest and marine habitats, species survival and the availability of freshwater. Widespread poverty is also driving the illegal trade in timber, wildlife and marine fish."

As well as all that, there about 150 large hydroelectric dams planned for the area, including several by the Chinese government.

It is feared the dams will affect the transport of sediment and the river's flooding cycle, and will drastically alter ecosystems.

Mr Chapman said that while the region must progress economically, that drive could not be allowed to destroy the astonishing array of species.

The WWF advocate a series of measures to stem the threat, the most important of which are sustainable development guidelines and legislation to stop the illegal wildlife and timber trade.

He said: "To help protect the biological diversity of the region while also providing for livelihoods and alleviating poverty, economic development and environmental protection must go hand-in-hand.

"What is urgently needed is a formal, cross-border agreement by the governments of Greater Mekong."

It is an ambitious target, but if the region is to yield further amazing species, it is one biologists hope will be met.

THE Annamite striped rabbit was discovered in rather alarming circumstances by British scientists.

Dr Rob Timmins, working with the Wildlife Conservation Society, found three carcases in a meat market in the rural town of Ban Lank in Laos in 1999. It is one of only two striped rabbits in existence and can be found in Laos and Vietnam.

THE woolly bat, kerivoula kachinensis, was identified in 2004 from Burma, but has since been revealed to inhabit a range of countries, including Cambodia, Laos, Thailand and Vietnam. Small in size, they inhabit tall forests. Their ears are rounded and barely extend above the top of the fur on their domed skull. The orange-brown fur is thick, long and fluffy and covers much of the face.

DR PETER Jger discovered the Heteropoda maxima in caves in Laos's Khammouan province seven years ago. It was to prove a significant find. With a colossal legspan of up to 30cm – the diameter of a dinner plate – the species is the world's largest huntsman spider. These spiders are not deadly to humans. They will bite if provoked, but the victim will suffer only minor swelling.

WITH its shocking pink colour and spiny body, desmoxytes purpurosea is unlike any other millipede. It was discovered last year in the Lansak area of Thailand, when several were found on limestone rocks and on the leaves of Arenga pinnata palms. Scientists suggest its bright colour is to alert predators of the animal's toxicity – its glands produce cyanide as a defensive mechanism.

THELODERMA licin, a smooth-skinned wart frog, was found in Thailand.

This genus of frog is characterised by its relatively small size, rough tubercles across the skin, angular snout, large eyes, distinct tymphaum and soft whistles as calls. The frogs spend most of their lives up trees, but do come down near the ground, especially after heavy rains.

A NEW species of rhacophorid frog, Chiromantis samkosensis, was identified in 2007 from Phnom Samkos in the north-western section of the Cardamom mountains in Cambodia.

It is distinguished from other species of Asian Chiromantis by having green blood and turquoise bones, among other unique characteristics.