Native peoples' survival crucial for environment.

Human cultures, like plant and animal species, are becoming extinct at unprecedented rates. Moreover, the fates of cultural and biological diversity are closely linked. Of the world's 6,000 languages--representing approximately the same number of cultures--half likely will disappear within a century as their speakers are driven off their territories and assimilated into dominant societies, according to a Worldwatch Institute report, Guardians of the Land: Indigenous Peoples and the Health of the Earth.

"Far from a vestige of the colonial past, the extinction of cultures has accelerated in this century as the modern economy has scoured the globe for resources and markets," says the report's author, Alan Thein Durning, a senior researcher at Worldwatch. As indigenous cultures vanish, so do vast numbers of animal and plant species unknown to Western science--as well as intimate knowledge of their use. Native peoples' homelands encompass many of the planet's last tracts of wilderness--ecosystems that shelter millions of endangered species, buffer the global climate, and regulate hydrological cycles.

"Even without considering questions of human rights and the intrinsic value of cultures, indigenous survival is a matter of crucial importance. We in the world's dominant cultures simply can not sustain the Earth's ecological health without the help of the world's endangered cultures."

Indigenous peoples encompass 4-5,000 cultures and total between 200,000,000 and 600,000,000 people, depending on how "indigenous" is defined. Descended from the original inhabitantsof an area taken over by more powerful outsiders, they remain distinct from their country's dominant group in language, culture, or religion. Their social relations often are tribal, and they commonly maintain strong ties to a subsistence economy. They are, or are descendants of, hunter-gatherers, fishers, nomadic herders, slash-and-burn farmers, or subsistence cultivators. Most consider themselves custodians and caretakers--not owners--of their land.

Whereas indigenous peoples exercised control over most of the Earth's ecosystems as recently as two centuries ago, the territory they now occupy has shrunk to an estimated 12-19% of the globe's land surface. Whole peoples...