The Nature Conservancy announced last week it will invest at least $1 billion to protect 200 high-priority natural areas in the United States and other international locations by 2003.

The organization's "Campaign for Conservation" so far has raised $435 million of its $1 billion goal.

The conservancy also is developing a "Blueprint for Saving the Last Great Places," which identifies sites and actions necessary to protect the current level of natural diversity in the U.S. and Canada. The blueprint will act as a guide as the conservancy takes action with local communities and other partners to protect these sites.

The campaign comes after the release of "Precious Heritage -- the Status of Biodiversity in the United States," written by scientists from The Nature Conservancy and the Association for Biodiversity Information.

The findings of the book and the $1 billion campaign were announced by Nature Conservancy President and CEO John Sawhill on March 16 at the Smithsonian Institution's National Zoological Park.

The book documents the presence in America of more than 200,000 native species, which is double the number previously estimated. It also highlights the U.S. -- home to 10 percent of all species found by scientists so far -- as the an important center of biological diversity.

"It's not enough to simply talk about the problem. We have to take action as well," Sawhill says.

The campaign also aims to use these protected sites as "on-the-ground classrooms" for testing new conservation strategies. These methods will reach out to local communities and partners while maintaining local livelihoods, to help protect entire ecosystems, watersheds and flyways, the Nature Conservancy reports.