by Eric Powell
The threat of vanishing biodiversity isn't limited to rain forests. According to statistics just released by the United Nations' Food and Agriculture Organization, two breeds of farm animal go extinct each week and one third of all domesticated breeds may disappear in the next 20 years. Some 18 percent of North America's domesticated animals are now gone; globally, 740 livestock breeds have been lost during the past century.
The world's growing dependence on a few popular breeds means the loss of unusual and desirable genetic variety. "We can't rely only on a handful of animals, because animal breeds are adapted to their special environments," says Beate Scherf, an animal genetic resources expert in the Food and Agriculture Organization's Rome office. The problem is particularly acute in the third world, where imported breeds are rapidly supplanting indigenous ones even though the new animals often do not bring the promised benefits. "When you transfer improved breeds from developed to developing countries, they probably won't produce as in their country of origin," Scherf says.
Native livestock is generally better adapted to regional climate and ecology and is less susceptible to endemic diseases. The Philippines's Banaba chickens, of which there are fewer than a thousand, fly into treetops to escape predators. Croatia's Turopolje pigs, which number around 50, are excellent swimmers and have thick, curly hair that helps them weather harsh winters. To prevent such unusual traits from being lost, the United Nations is encouraging conservation efforts like those under way in Poland, Malaysia, and Vietnam. Even so, 1,335 unique farm animals now face oblivion. "Biotechnology can improve existing breeds but can't replace them once they're lost," says Scherf.