Hidden treasure

In a remote region of Ecuador, a botanist has found his personal El Dorado – a hoard of orchid species unique to the area. Fred Pearce investigates

High in the Andean mountains of Ecuador are cloud-covered mountains that no satellite has ever observed and no cartographer has ever mapped. Up there somewhere, the Incas are said to have hidden their treasure when the Spanish came calling half a millennium ago. Bounty hunters have so far failed to find the hoard. But Lou Jost, a US scientist and botanical adventurer, claims to have discovered the mountains' ecological El Dorado – its vast collection of endemic orchids. His findings are changing our understanding of how and why plant species unique to particular localities survive.

Jost has spent six years living in the Ecuadorian Andes, collecting dozens of new orchid species in the remote cloud forests and valleys. He operates alone, without the help of any academic body. His tiny greenhouse, on the roof of his apartment in Baños, harbours a collection of plants found nowhere else on the planet.

Most of his collection comes from the watershed of the river Pastaza, which carves through the Andes and down into the Amazon rainforest. The valley has more endemic orchids than anywhere else in the world. The Pastaza valley is the deepest and straightest in the eastern Andes. Every afternoon a hot wind blows in from the Amazon, bringing huge volumes of moisture that evaporates to form near-permanent clouds over the mountain ridges that flank the valley. In these wet, sunless environments, dozens of species of orchid have evolved, often with flowers so fragile that they would collapse in minutes anywhere else. "Each species seems to specialise in a particular combination of rain, mist, wind and temperature," says Jost. Some grow by the thousand on a single ridge, but disappear just a few metres below the top.

Ecuador is a hot spot for plants. Peter Jorgensen of the Missouri Botanical Gardens reported in the journal Science last November that current records show more than 4,000 species native to a country the size of Nevada, with four out of five threatened with extinction. The Pastaza valley is the heartland of that diversity.

Jost has identified 90 endemic orchids around the valley over six years' study. On one red-letter day recently, he found four new species of Teagueia orchids in a single patch of moss on Mount Mayordomo. That single find raised the number of known Teagueia species from six to 10. And since that day, he has found another 16 long, creeping Teagueia orchids on the mountain.

Meanwhile, he and other botanists have found 197 unique plant species in the Pastaza valley – more than the 180 found on Ecuador's other biological treasure house, the Galapagos Islands. "The Galapagos is fully studied, but up here are huge areas that have never been explored." The rarest orchids are no shrinking violets in their own habitat. "High in the clouds, you can come across whole areas of forest smothered in a single species of orchid that probably exists nowhere else on earth. It is amazing."

Jost believes his findings conflict with conventional thinking about the evolution of endemic plants. "The usual view is that endemism is cause by geographical isolation: the plants could grow elsewhere, but they cannot escape the confines of their single habitat. That's not true for these orchids," he says. "They have tiny, dust-like seeds that can spread easily. But the colonisations fail because they literally cannot grow anywhere else."

This might be good news for the survival of biodiversity if, as expected, the planet warms in the coming decades. Endangered plants may be better at seeking new territory than previously thought. But the question remains: if they are so picky about climate, will they find anywhere suitable to go?

A widely respected and published botanical Indiana Jones, Jost is never happier than when clambering through the bone-chillingly cold, damp Andean valleys. As he says, "The only way to discover the botanical secrets up there is to walk every ridge and valley." Some parts are guarded by tenacious Shuar Indians, descendants of the Inca gold-hoarders. But most are empty, except for the occasional mountain tapir and bear. "There are mountain ridges here that no scientist has ever visited," Jost says. But whether braving bears, frostbite or belligerent locals, he rejoices in following in the footsteps of his hero, the 19th-century English botanist Richard Spruce, who trekked through the Pastaza valley in the 1850s. "He discovered ferns and liverworts that nobody has seen since."

I met Jost in mid-December, just after he returned from his latest expedition. He apartment was strewn with plant samples, and in his rooftop greenhouse he was ready to show off intricate orchid flowers from past expeditions, many of which had opened their petals under his tender care.

"You have to know what you are looking for when you go orchid hunting," he says. "The flowers are only a few millimetres across and usually hide under the leaves. Often the plants are not in flower. If I spot what I think is a new species, I can often only be sure when I bring it back here to wait for the flower to appear."

The survival of these plants away from the cloud forests is precarious. Jost keeps the greenhouse air cool with an electric fan, which is dependent on the town's fitful power supply, and a passive air conditioner that draws in air over permanently wet tiles. He maintains humidity with an ingenious paperweight balance. When a packet of plant stalks on the balance becomes too dry, it loses weight and the balance shifts, switching on a humidifier in the bathroom below. "It's not perfect. But it means I can go away on plant-collecting expeditions and be fairly sure my specimens will still be alive when I return," he says.

But can Jost's orchid El Dorado survive? The Pastaza valley is ever more vulnerable to development. Tourists flock to Baños, and a new asphalt road will soon pass through the valley. Farmers are clearing the hillsides for pastures and to grow crops. The valley is a growth corridor between two national parks, the Sangay and Llanganates to its north and south. "Ironically, there are probably more unique species in the valley than in the protected parks," says Jost.

Last December, following biological surveys by Fundación Natura, a national environment group, the mayor of Banos declared the valley an ecological corridor with a new development strategy aimed at preserving habitat such as cloud forests. And the WWF awarded the initiative its accolade, the Gift to Earth award. One aim, says Xavier Viteri of Fundación Natura, is to encourage more ecological and scientific tourism. "Local business is getting wise to the idea that these kinds of tourists bring money and fill hotels – but to keep them, you have to keep nature as well."

Jost agrees. After all, he came to Baños as a scientific tourist, and stayed to put the valley on the ecological map.