Researchers have uncovered an intriguing correlation between cultural and biological richness: Nations with the highest numbers of endemic languages tend to also have the highest levels of biodiversity.

Conservationist David Harmon, author of In Light of our Differences: How Diversity in Nature and Culture Makes Us Human (Smithsonian Institution Press), studies this link. He has found that linguistic and biological diversity were concentrated in countries that possessed a variety of terrains, climates, and ecosystems, such as Mexico, Brazil, and India. Similarly, island territories cleaved by mountains and rivers (think Indonesia, Australia, and New Guinea) have been havens for both unique languages and locally adapted species.

"If you've got a society that has lived in the same place for hundreds or thousands of years, they'll be changing the species composition by selective hunting and use of plants," Harmon says. Because humans modify their environment as they adapt to it and then transmit their knowledge through language, ecosystems and languages co-evolve. In turn, Harmon adds, "when indigenous languages die out, there's a self-reinforcing downward cycle: The language is not spoken, and people are not as intimately involved with the local biodiversity. So they are not going to take care of it and value it the way they did, and it will be more vulnerable to development."

In an effort to better understand the links between biological, cultural, and linguistic diversity, Harmon cofounded Terralingua, an organization devoted to preserving what is now being referred to as "biocultural" diversity. To learn more, log on to www.terralingua.org.