Hey, we’re richer than we thought!

The latest inventory of life in the United States has turned up an extra 100,000 species. The nation has at least 200,000 animals, plants, and fungi, according to Precious Heritage (2000, Stein et al., Oxford University Press). That impressive total doesn’t include any of the national wealth of algae and other protists, bacteria, or viruses.

The ringed map turtle lives only in the Pearl River system of Louisiana and Mississippi. G. Sievert/Precious Heritage

Relentless burrowing for data in recent surveys and studies doubled previous estimates, explains coeditor Bruce A. Stein of The Nature Conservancy in Arlington, Va. “We looked at peanut worms; we looked at tunicates, at spoon worms . . . ,” he recalls.

Still, the bulk of species falls into more familiar categories: at least 96,406 insects, centipedes, and millipedes; 37,800 fungi; 15,320 flowering plants; 9,557 spiders and their arachnid relatives; 7,500 mollusks; 6,000 flatworms; and 4,900 vertebrates.

What doesn’t look so familiar are the country’s international rankings. “Who thinks of the United States as the crayfish capital of the world?” marvels botanist Stein. Yet the 322 U.S. species represent 61 percent of the world’s crayfish species. Of the U.S. share, 96 percent live in no other country.

The United States also ranks first in the world in abundance of freshwater mussels (292 species, or 29 percent of known species) and freshwater snails (661, or 17 percent). And Hawaii alone hosts the greatest known proliferation of kinds of fruit flies, about 1,000 species.

At least a third of the nation’s species should arouse conservation concern, according to a preliminary estimate by The Nature Conservancy and the Association for Biodiversity Information in Arlington, Va.

“The good news is, Americans enjoy an incredibly rich natural heritage,” Stein says. “The bad news is that Americans risk losing much of this natural wealth.”

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.