杏吧原创

WHAT links a warming drink once sold on the streets of London, Turkey鈥檚 traditional ice cream and a wobbly brown cake that鈥檚 fast becoming Zambia鈥檚 favourite snack? Orchids. The main ingredient of all three is made by pulverising the tubers of some of the world鈥檚 most exotic plants.

In England, tea and coffee ousted their orchid-based rival centuries ago. In Turkey and Zambia, though, demand for tubers is soaring, fuelled by an increasingly prosperous urban middle class with a taste for authentic foods. But there鈥檚 a dark side to this growing appetite for traditional dishes: the tubers they are made from are taken illegally from the wild. 鈥淐ollection is ruthless,鈥� says botanist Hugo de Boer of Uppsala University in Sweden. 鈥淚t has reached a point where entire populations have gone and others are on the point of collapse.鈥�

For centuries, people in Turkey and its former empire have enjoyed a drink, sweets and a slow-melting, stretchy ice cream made from salep, a flour produced by grinding the tubers of bee and butterfly orchids and their kin. At the height of the Ottoman Empire, the warm, creamy drink made from salep became popular as far away as England and Germany. Street vendors still sell it in Greek cities in winter, but it is Turkey鈥檚 consumption of the drink and dondurma 鈥� the revered traditional ice cream 鈥� that poses the greatest threat to the region鈥檚 orchids. 鈥淐onsumption has really taken off in the past decade,鈥� says de Boer.

In parts of East Africa, people ate orchid tubers during hard times rather than as a delicacy. The Bemba people of north-east Zambia, however, turned this famine food into a more regular part of their diet in the shape of chikanda, a soft, savoury cake made by boiling orchid flour, peanut flour and ash, then baking the mixture until just set. Once a cheap and tasty substitute for meat, today chikanda is seen as part of Zambia鈥檚 culinary heritage. 鈥淲e thought consumption would fall as people grew more prosperous, but the opposite has happened,鈥� says de Boer. Chikanda is now available in towns and cities across the country, sold by the slice in markets and as a 鈥渢aste of Africa鈥� in big-city restaurants. It鈥檚 even available from supermarkets.

The surge in demand for these products has seen the small-scale collection of tubers transformed into a flourishing commercial trade, with organised networks of middlemen offering cash for tubers. The results have been catastrophic for orchids. 鈥淐ollectors dig up orchids with a spade or a hoe, take the fresh tuber and throw away the plant,鈥� says botanist Abdolbaset Ghorbani at Uppsala University.

The scale of the harvest is staggering. It can take between 1000 and 4000 tubers to produce a kilo of salep. In Turkey, an estimated 30 tonnes of tubers from 38 species are harvested each year. With many orchids becoming rare or locally extinct, traders have been forced to look to neighbouring Iran for supplies. Ghorbani estimated that between were collected in northern Iran in 2013, the majority exported to Turkey. In Greece, a revival of interest coupled with the economic crisis has also prompted . 鈥淎cross the whole region, collection is increasing, and it will continue to increase unless something is done to stop it or all the tubers are gone,鈥� says Ghorbani.

The picture is much the same in Zambia, where collectors target as many as 80 different orchids, mostly species of Disa, Habenaria and Satyrium, which have large, starch-packed tubers. 鈥淟andowners report that orchid-rich grasslands are now almost bare,鈥� says Ruth Bone, a conservationist at the Royal Botanic Gardens at Kew, London. Increasing demand has led to trade from Angola, the Democratic Republic of the Congo, Mozambique and Malawi. But the greatest traffic in tubers is from Tanzania; an estimated 3.5 million of them were brought illegally across the border in 2014. Harvesting from Tanzania鈥檚 Southern Highlands threatens as many as 85 species, some found nowhere else. Collection is rife even inside Kitulo National Park, which was set up specifically to protect orchids.

How then to prevent these plants being eaten to extinction? There are already laws protecting orchids, and under the Convention on International Trade in Endangered Species (CITES), exports and imports of any orchid or orchid product is illegal without a permit. But with limited resources, enforcement is tough. And attempts to clamp down on illegal trade are hampered by difficulties in identification.

Tubers have few distinguishing features 鈥� fewer still once dried and sliced. So what are the chances of proving a sack of flour or a slice of chikanda contains orchids, let alone what species? The answer is that , de Boer and his colleagues at Uppsala are finding. 鈥淲e are able to isolate orchid DNA from powdered tubers and we鈥檝e even got it from samples of ice cream, hot drinks and chikanda,鈥� says Ghorbani. Using a technique known as , the team can sequence all the DNA fragments in a sample and compare them against the DNA of known orchids until they find a match. 鈥淏arcoding can show which species are most commonly collected, and help track those species in trade,鈥� says Ghorbani. 鈥淒NA sequencing also makes it possible to pick out small genetic differences that help to identify the region they came from, which can help to identify the places where we need to focus conservation efforts.鈥�

鈥淚n Turkey, some 30 tonnes of tubers from 38 species are harvested each year鈥�

Alternative ingredients

Another strategy is to reduce demand. Some of the qualities attributed to orchids can be replicated with other ingredients. Glucomannan, the polysaccharide responsible for dondurma鈥檚 stretchiness and high melting point, and chikanda鈥檚 spongy texture, can be replaced by synthetic glucomannan or guar gum. Where orchid flour is used as a thickening agent, rice flour, cornstarch and flours made from other roots serve just as well. And although the distinctive earthy flavour of orchid tubers is harder to recreate, other flavours usually overwhelm it. Hot drinks made from salep are highly spiced with cinnamon and cardamom, while chikanda tastes more of peanuts and is generally served with chilli sauce.

In Turkey, ice cream manufacturers already use more of these substitutes than genuine salep. But the cachet attached to products made from the 鈥渞eal thing鈥� continues to drive demand for wild tubers. In Zambia, enthusiasm for real chikanda may be even more deep-rooted. 鈥淲e don鈥檛 know much about its cultural significance,鈥� says Bone. 鈥淭here might be more to its popularity than its texture and flavour.鈥�

Commercial production would also ease the pressure on wild orchids. But it鈥檚 not easy. There have been some attempts to cultivate salep orchids by tissue culture, although none has yet reached the market. In Zambia, a different approach is needed. In and around the country鈥檚 orchid grasslands, as many as 80 per cent of households supplement their income by collecting tubers, a job done mostly by women and children. Shrinking orchid populations mean they must travel farther and take greater risks, crossing national borders and trespassing into reserves. 鈥淭hese are some of the world鈥檚 poorest people and we need to protect their livelihoods if we are to protect the orchids,鈥� says Bone.

Last summer, Bone and a team from Zambia, Uppsala, South Africa and the UK began a pioneering project to conserve chikanda orchids. They are tracking the tuber trade with the help of DNA barcoding, alerting consumers to the origins of their favourite snack and the damage done by the harvest, and developing conservation programmes with local people. But the project鈥檚 ultimate goal is to turn gatherers into gardeners. 鈥淏y growing their own orchid crop, women would have a more reliable source of income without risking their safety or taking their children out of school,鈥� says Bone.

Raising orchids is not as simple as growing potatoes, however. Commercial growers mass-produce plantlets from tissue cultures spiked with the nutrients they need to grow. To culture chikanda orchids, you first have to find out what they need (see 鈥�Fungal partners鈥�). To make the task more difficult, every species has its own requirements.

Kew鈥檚 Jonathan Kendon and colleagues at Copperbelt University in Kitwe, Zambia, are working on what it takes to persuade seeds from wild orchids to grow in culture and how to turn lab-raised seedlings into tough, healthy plants. If some species prove better suited to village gardens than others 鈥� because they are easy to grow or are quick to produce a crop 鈥� the university nurseries will grow them in bulk for distribution. Eventually, though, local communities will need to be self-sufficient, collecting their own seeds, propagating them in low-tech nurseries and rearing tubers in a wide range of much tougher conditions. 鈥淚t鈥檚 a big leap from university nursery to village garden,鈥� says Kendon. But the potential pay-off is huge.

The newly acquired expertise will be invaluable not just in Zambia but wherever orchids are being harvested from the wild. If local people grow local orchids, everyone wins: consumers get the real thing, and rural families can make extra money from the flowers as well as the tubers. The biggest winners, though, will be the orchids.

This article appeared in print under the headline 鈥淓aten to extinction鈥�