29 April 2011 Last updated at 20:05 ET

Ecuador's highland bugs key to biodiversity

By James Painter Antisana Glacier, Ecuador

Of all the things to worry about, it is not immediately obvious why anyone would choose some tiny bugs living in a stream some 4,500m (14,765ft) up in the Ecuadorean Andes.

But 36-year-old French river ecologist Olivier Dangles is passionate about them.

His hands shivering from the cold, he pokes at the writhing body of a tiny aquatic invertebrate he has just found in his sample. It will eventually become a fly.

"You could say some of these invertebrates are the polar bears of the high Andean streams," he says.

"There are at least five types here in danger of becoming extinct because of the disappearing glaciers which feed the streams where they are found."

Crowded out

It is hard to see how something you can only see properly under a microscope - and with complicated names such as Parochlus (Chironomidae, Diptera) - could rival the polar bear as a symbol of climate change.

But Professor Dangles and his fellow scientists at the French Development Research Institute and the Pontifical Catholic University of Ecuador are convinced that the rapidly retreating Andean glaciers offer an extra layer of stress not just to water supplies but also to the delicate mixture of fauna and flora in the region.

Since 2008, they have been collecting samples downstream from the majestic Antisana glacier, 40km (25 miles) south of the equator and an hour's drive from the capital, Quito.

Like many other glaciers in Ecuador, the part of the glacier feeding the streams has retreated around 200m since 1997.

Prof Dangles points to a nearby glacial stream which is milky white owing to small particles of silt carried down from the glacier.

The rain-fed streams are brown from organic matter, while spring-fed ones are clear.

"These five types of fly larvae can only live in this type of glacier-fed streams," he explains.

"'The streams have a particular combination of low levels of minerals, oxygen and organic matter."

Lots of other larvae thrive in the rain-fed and spring-fed streams which abound here.

But the five found only in the glacial-fed streams would get "crowded out" by competitors in the other streams, according to Prof Dangles.

They also have the capacity to "crouch down" behind rocks to cope with the constantly-changing flow of the water stream from the glacial melt. But once the glacier melts, they probably will not be able to survive.

Vulnerable species

Other scientific studies have shown that in general higher temperatures represent a considerable threat to the biodiversity found at high altitudes.

For example, several studies have documented the vulnerability of plant and animal species in the Alps to recent warming.

And in the Glacier National Park in Montana, a rare stonefly known as the Zapada glacier which lives in glacial-fed streams is considered especially vulnerable, as the water it lives in increases in temperature.

But why should anyone care if five types of fly disappear in Ecuador?

"What's new that we have discovered here is that there is more variety of species when there is a small amount of glacial-fed water in the streams than when there is none, but we still need to find out why," says Dean Jacobsen, a Danish river ecologist from the University of Copenhagen who started the project.

"So if we have no water from the glaciers in the future, we would get less variety of species or biodiversity in these places."

It is a complex piece of research, which Prof Dangles and Prof Jacobsen are publishing later this year.

But the essential message is that the threat from the disappearing glaciers is not just that certain species of wildlife could be lost from the glacial-fed streams, but that the surprising variety of species in all the streams could also be reduced.

Squeezed

The area where Prof Dangles and his colleagues are carrying out the research is in the Ecuadorean paramos, a vast area of highland grassland which stretches from southern Venezuela to northern Peru.

Marcos Villacis, a water expert from Quito's National Polytechnic School says the effect on the paramos of warmer temperatures, changing rain patterns and less water contribution coming from glacial melt needs to be studied carefully.

"The paramos act like an enormous sponge, absorbing then releasing water," he says.

"For example, over 90% of the supply of water to La Mica system which feeds nearly 30% of Quito's water consumption comes from the paramos."

This part of the Ecuadorean paramo currently supports a wide variety of wildlife, including waders such as the black-faced ibis and the Andean lapwing, which could be threatened by long-term changes to their habitat.

Prof Dangles says man-made climate change is just one of many threats to individual species and biodiversity in the paramos.

For example, the band of altitude where his team is working has unique conditions which are being squeezed from below, as well from above.

On the way to the research site, you drive past new areas of potato fields as the agricultural frontier expands upwards.

"There are multiple pressures on the paramos. But these changes are happening so quickly," says Prof Dangles, who has lived in Ecuador for the last five years.

"They are taking place within years, not decades."