SCIENCE

Biologists estimate that about 99 percent of microbes in nature have never been cultivated or studied in detail.

"Our study is part of the continuing quest to . . . answer the big question, 'What new microbes are out there and what are they doing?' " Brenchley said in a written description of the project.

-- David Brown

Panda Population Decline Halts

In a result that cheered conservationists, experts have counted 1,600 giant pandas living in the forests of east central China, nearly 50 percent more than previously known to exist, the World Wildlife Fund reported last week.

Karen Baragona, head of the fund's panda program, said the census, compiled over four years beginning in 2000, suggested that a decades-long decline in the endangered panda's population appeared to have been halted, if not reversed.

"We believe the numbers did not increase that significantly, and that it is more likely that the last survey [in the 1980s] was an underestimate," Baragona said in a telephone interview. "But we have significantly more pandas surviving today, and a phenomenal opportunity to protect their habitat."

Baragona credited the Chinese government's 1998 ban on logging the temperate upland forests around the headwaters of the Yangtze River as the critical event in arresting the pandas' decline.

Pandas, native only to China, live in a patchwork of forested mountains in the Chinese provinces of Sichuan, Shaanxi and Gansu. While conservationists work to reconnect these areas through reforestation, Baragona said the most important immediate task in these would-be transit "corridors" is to ensure that pandas have enough bamboo to eat during their journeys through them.

"Pandas don't need pristine forest except for mating and denning," Baragona explained. "But they do need a lot of bamboo, because they don't eat anything else and they don't digest it very well. Bamboo is the limiting factor."

-- Guy Gugliotta