Heather Pringle writes: In a spacious, art-filled apartment in Brasília, 75-year-old Sydney Possuelo takes a seat near a large portrait of his younger self. On the canvas, Possuelo stares with calm assurance from the stern of an Amazon riverboat, every bit the famous sertanista, or Amazon frontiersman, that he once was. But on this late February morning, that confidence is nowhere to be seen. Possuelo, now sporting a beard neatly trimmed for city life, seethes with anger over the dangers now threatening the Amazon’s isolated tribespeople. “These are the last few groups of humans who are really free,” he says. “But we will kill them.”

For decades, Possuelo worked for Brazil’s National Indian Foundation (FUNAI), the federal agency responsible for the country’s indigenous peoples. In the 1970s and 1980s, he and other sertanistas made contact with isolated tribespeople so they could be moved off their land and into settlements. But Possuelo and others grew alarmed by the human toll. The newly contacted had no immunity to diseases carried by outsiders, and the flu virus, he recalls, “was like a suicide bomber,” stealing into a village unnoticed. Among some groups, 50% to 90% died (see sidebar, p. 1084). In 1987, Possuelo and fellow sertanistas met to try to stop this devastation.

In Brasília, a futuristic city whose central urban footprint evokes the shape of an airplane, the frontiersmen agreed that contact was inherently damaging to isolated tribespeople. They drew up a new action plan for FUNAI, based solidly on the principle of no contact unless groups faced extinction. They recommended mapping and legally recognizing the territories of isolated groups, and keeping out loggers, miners, and settlers. If contact proved unavoidable, protecting tribespeople’s health should be top priority.

The recommendations became FUNAI policy, and a model for other countries where isolated populations are emerging, such as neighboring Peru (see companion story, p. 1072). In remote regions, FUNAI has designated a dozen “protection fronts” — official front lines in the battle to defend isolated groups, each dotted with one or more frontier bases to track tribes and sound the alarm when outsiders invade. In an interview in February, FUNAI’s interim president, Flávio Chiarelli, told Science that his agency is “doing great” at protecting the country’s isolated tribes.

But some experts say that as the pace of economic activity in the Amazon accelerates, the protection system that was once the envy of South America is falling apart. [Continue reading…]