Twice as many plants have gone extinct than birds, mammals, and amphibians combined

When scientists talk about recent extinctions, birds and mammals get most of the attention. But the first global analysis of its kind finds that twice as many plants have disappeared than birds, mammals, and amphibians combined.

Researchers reviewed published research, international databases, and museum specimens such as grasses from Madagascar (pictured), tallying up 571 plants species that have gone extinct in the past 250 years. One reason the total exceeds that of well-studied animals is that there are simply more kinds of plants. Looking at percentages, the situation is worse for mammals and birds; an estimated 5% of those species have gone extinct, compared with 0.2% of plants.

The losses include the Chile sandalwood tree in the South Pacific, exploited for its fragrant timber. It was last seen on Robinson Crusoe Island in 1908. (The extinction rates among plants have been highest for trees and shrubs on islands—which often have species that occur nowhere else—and in regions with rich diversity, especially the tropics and in Mediterranean climates.)

Just a few years later, the world lost the banded trinity (Thismia americana), a leafless plant that grew entirely underground except for its flowers. Most species of this kind of plant grow in rainforests, but T. americana was first described in 1912 in a sandy wetland in Chicago, Illinois, and was wiped out by development.

The total of 571 extinct plant species is four times higher than the official listing kept by the International Union for the Conservation of Nature in Gland, Switzerland, the team reports today in Nature Ecology & Evolution. Even so, it is probably still an underestimate, as less is known about the status of plants in Africa and South America than on other continents. Many of these species may vanish, too; a major review of the status of global biodiversity recently estimated than more than a million species (including 14% of plant and animal diversity) are threatened with extinction.