Soon after peasant farmers first led plant explorers to wild stands of Zea diploperennis (perennial maize) in Mexico's Sierra de Manantlan in the late 1970s, plant breeders hailed the discovery as one of the botanical finds of the century. The rare perennial maize proved to be resistant to seven viral diseases that plague domesticated maize, and scientists predicted that Zea diploperennis could be worth as much as $4.4 billion to the commercial maize (corn) industry. Conservationists called for the establishment of a nature preserve to protect the rare maize in its natural habitat because they feared that poor farmers living nearby, in constant need of grazing land for their cattle, would soon wipe out the few remaining patches of wild maize by grazing cattle in the area. A nature preserve was eventually established, and peasant farmers no longer threatened the rare diploperennis. But within a few years, the forest began to invade the fields of wild maize. The plants were crowded out and began to disappear. Scientists soon realized that the local farmers had been intentionally conserving the wild maize by using a traditional practice of grazing their animals on dry fodder during the dormant season. Local farmers controlled the growth of the surrounding forest without harming the rare perennial maize plants. ...

... This story illustrates not only the tremendous value of rapidly disappearing crop genetic diversity, but also the fact that it is impossible to talk about the conservation of species and ecosystems separate from farm communities and indigenous peoples. The world's main food and livestock species have their centers of genetic diversity in the South. Generations of farmers in the tropics and sub-tropics have consciously selected and improved plants and animals that are uniquely adapted to thousands of micro-environments. Today, farming communities in Africa, Asia and Latin America are the primary custodians of most of the earth's remaining agricultural biodiversity. They are also carriers of unique knowledge about genetic resources and entire ecosystems.^[1]