Anastasia Valiente sits out with her machete and her expert eye for the plants and herbs that grow wild in the local area. But however long she forages（搜寻粮草） among the dense（密集的） grassland（草原）, the plant she's here for is nowhere to be found. Anastasia is looking for stevia, a plant in growing demand due to its sweet tasting leaves. A long time ago stevia grew wild here but not anymore. I've never seen it myself but my mother told me where it used to grow. Along with other medicinal（药物的） herbs stevia used to grow wild on the other side of this fence.

  The plant was native here. Today this is pasture（草地） land used for grazing（放牧） livestock（牲畜）. The diversity of native flora（[罗神]花神） has deteriorated（(使)恶化） and others are profiting from indigenous（本土的） inhabitants' ancient knowledge. Anastasia Valiente is a member of the Paitavitera, an indigenous people in northeastern Paraguay. She's from Itavazu, a small reservation close to the Brazilian border. The people here live from their own small holdings（举办） or from jobs on large scale farms in the vicinity（邻近）.

  The pai maintain a traditional way of life that is under acute（敏锐的） threat. Anastasia Valiente gathers and sells medicinal plants. Her mother and grandmother taught her the properties and benefits of endemic herbs and roots. The Paitavitera have a wealth of knowledge about medicinal plants. It's the women who preserve this knowledge and pass it on to future generations. Luis Arce stops by for a cup of mate.

  He's the leader of the 500 strong reservation. Centuries ago the pai discovered the sweet taste of stevia leaves and began using the plant both as a food additive（附加的） and for rituals（典礼）. But Luis and Anastasia drink their mate tea unsweetened as wild stevia is now virtually extinct in Paraguay. The pai people and their traditional herb remedies（治疗） are being squeezed（压） out by the farming industry. Their knowledge of stevia's sweetening（使变甜） properties was appropriated. It was taken away from us to other countries without our consent（同意）.

  We respect stevia and are the guardians（[法] 监护人） of our plants. We want to preserve our stevia and hope we'll be able to start farming it again here. There are around 15,000 paitavitera and while they have little land or income to live off today, global enterprises（企业） have capitalized on stevia's sweet benefits. It's a classic case of biopiracy. Many brands of soft drinks candy and chocolate contain stevia or to be more precise the chemical compounds that give the plant its sweet taste stevial glycosides（[化]配醣）. The reason stevia is so special is that its leaf extracts are up to 300 times sweeter than table sugar and contain zero calories（卡路里（热量单位））.

  With the increasing prevalence（流行） of diabetes, the growing debate over a sugar tax and the negative aspects of artificial sweeteners, stevia has become a global business for the food industry. Worldwide the market for stevia-based sweeteners is worth around 500 million dollars. That's predicted to almost double by 2028 with an annual growth rate of almost nine percent. Wealth that the paitavitera are not party to. Others are making money from their traditional insights about this natural resource. The pie however are in urgent need of financial means to protect their land and local biodiversity（生物多样性）.

  The reservation is surrounded by an expanding array（数组） of cattle（牛） ranches（大农场） and soy and eucalyptus monocultures. And while the government supports the big commercial farms, the pie face intimidation and threats. The farm workers shoot at us which is why we no longer have access to the resources that used to belong to us. But Luis Arce and his community are fighting back. Together with activists（积极分子）, paitavitera people in Paraguay and Brazil are trying to claim at least a small share of the stevia market. What they want is compensation（补偿）, the restoration（恢复） of their land and the preservation（保存） of stevia in the few places it still grows wild.

  It's a trying and time-consuming undertaking（工作） not made easier by the individual communities living far apart from each other. But there's a crucial step on the horizon（地平线） for the pie. In Paraguay the stevia business seems to have lost relevance（ 相关性）. These days cultivation（培养） here is minimal（最低的）. Today's major producer nations such as China（瓷器） and the US have taken possession of the commodity（日用品） with corporations cashing in on its beneficial properties. They simply grow stevia themselves leaving the indigenous communities empty-handed.

  The government in Asuncion has an at best half-hearted commitment to the interests and concerns of the pie. Agronomist Miguel Lovera finds that unacceptable. He's been campaigning in support of the demands of indigenous people for years. This is a stevia plant he's growing in his garden. I can actually just take a leaf and eat it as candy. It's delicious.

  Miguel Lovera is all too familiar with how the story turns sour. It began when a Swiss botanist（植物学家） introduced the plant to Europe in the 19th century. Although it wasn't until the 1970s that Western researchers became interested in stevia's potential. They actually relied on the traditional knowledge of the Pinta Vittora people, the Guaraní living there, to show them where the plants were. They took it basically with no consent of the Pinta Vittora. That's the first thing, that's the first act of biopiracy.

  The fact that they didn't consult with them constituted（组成） biopiracy. Biopiracy refers to the appropriation of genetic resources and knowledge about them without asking for consent or offering anything in return. It might rarely be in the headlines in the Western world, but biopiracy is a widespread phenomenon. The areas most typically targeted by biopirates are those with a rich biodiversity, located primarily in the southern hemisphere（半球）. Many of them are in the Amazon region, India and the Cape（[地理] 海角） of South Africa. The genetic resources from such regions cover not just plants like stevia, but also animals and microorganisms, all of which have enormous potential for the food, pharmaceutical（制药（学）的） and cosmetic sectors.

  And it's precisely in these regions where biodiversity is frequently under threat and in particular need of protection. Miguel Rivera is on his way to the herb market in Asuncion. Using traditional insights about medicinal plants enables researchers and corporations to save a lot of time and money in their quest（寻求） for near active and profitable（有利可图的） ingredients. Miguel Rivera knows that the potential is far from exhausted. His native Paraguay is a treasure trove（被发现的东西） for big pharma. There is a lot of value still.

  They have many, many options in the Paraguayan pharmacopoeia, traditional pharmacopoeia, to treat many ailments.