Giant pandas are highly endangered, particularly in the Xiaoxiangling Mountains on the Tibetan plateau's eastern edge. When researchers led by ecologist Wei Fuwen of the Chinese Academy of Science's Institute of Zoology in Beijing screened DNA from 142 droppings collected from the area, they traced the scat to just 32 individuals.

Genetic analysis showed that the pandas' numbers had plummeted about 250 years ago, a time when Qing dynasty policies were encouraging farmers to settle the mountains. The booming human population's need for land and firewood whittled away the pandas' forest habitat by about 90% to two patches, split by a nationalhighway, totaling 800 square km.

Unlike larger panda populations in other protected habitats,the Xiaoxiangling pandas don't have the numbers or the geneticdiversity to survive long term without new blood, Wei's teamargues in a paper published online this month in Conservation Biology. In response to preliminary results, the governmentmoved one female panda to the area's Liziping reserve in April 2009.

"It's urgent to pay special attention to these kinds of isolated,small populations," says Wang Hao, a conservation biologist at Peking University, who was not involved in the work. But connecting and expanding the patches is also crucial, he says.Only then will "the increasing panda population have living space."

(http://www.sciencemag.org/content/vol328/issue5978/r-samples.dtl)