More Wild Pandas Than Thought, Dung Study Reveals
for National Geographic News
|June 22, 2006|
Wild giant pandas may be much more common than previously thought, scientists announced this week.
New population estimates for the endangered, bamboo-eating creatures indicate there could be almost twice as many of them living in the wild than past estimates have suggested.
The new study, based on DNA analysis of panda dung, indicates that up to 3,000 wild pandas now prowl the remote mountain forests of central China (map of China).
Results of the last national panda census, published in 2004, put the population at around 1,600.
The international team behind the study says their latest population estimate suggests the threat of extinction is now receding for the giant panda.
Michael Bruford of the School of Biosciences at Cardiff University in Wales and Fuwen Wei of the Institute of Zoology at the Chinese Academy of Sciences in Beijing led the research.
"Our results found that previous surveys underestimated the [panda] population," Bruford said.
"These findings indicate that the species has a much better chance of long-term viability, although we must not become complacent, since the population size is still perilously low."
The study focused on the Wanglang Nature Reserve, which was established in 1963 in Sichuan Province to protect giant pandas and other threatened wildlife.
Despite their size and distinctive markings, pandas are notoriously hard to survey because of their solitary nature and the rugged, bamboo-covered terrain they inhabit (kids feature: panda fun facts).
Researchers therefore employed a newly developed panda surveying technique using DNA recovered from the mammals' dung.
Previous population estimates had also relied on panda dung, but those analyses had looked for different-size bite marks on partially digested bamboo stems.
"Even the ecologists working in the field all the time rarely see pandas, which is why they have used poop [in surveys] as well," he said.
"Pandas defecate up to 40 times a day."
Bruford says the DNA fingerprinting technique provides a more accurate picture than an analysis of the dung's content.
"You get a standard genetic profile, just as you would use to try to catch criminals," he said.
The DNA tests indicated that some 66 pandas now live in Wanglangmore than twice the figure estimated by a 1998 survey.
The researchers say that population growth cannot explain such a big difference in numbers and that the previous survey likely underestimated the size of the Wanglang population.
Writing in this week's issue of the journal Current Biology, the team says similar disparities may well exist for other key giant panda reserves. This means there could be many more pandas throughout China than previously estimated.
"There may be as many as 2,500 to 3,000 giant pandas in the wild," the team concluded.
As well as allowing researchers to identify individual pandas, the unique DNA profiles provided other information, such as an animal's gender and the size of its territory.
The study also showed that the Wanglang pandas have plenty of genetic diversity, despite concerns among conservationists that habitat loss has isolated some wild panda populations, leaving them vulnerable to inbreeding.
"We didn't find any evidence for that in our study," Bruford said.
He notes that wider DNA profiling of wild pandas should give a better indication of the extent to which panda conservation efforts in China are helping to boost numbers.
"If we really want to see whether or not the population is genuinely increasing throughout its range, then we clearly need to do this in other reserves," he said.
WWF, the international conservation organization that has the popular black-and-white mammal as its symbol, welcomed the new study.
Mark Wright, conservation science advisor at WWF U.K., described the team's findings as "potentially exciting and promising news."
But, he says, wild panda numbers still remain at "perilously low" levels.
WWF highlights habitat loss as the major long-term threat to the survival of giant pandas in the wild.
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