The population of rare Black-necked Cranes wintering in west
China's Tibet Autonomous Region this year hit a record
high to 6,900, 3,000 more than that of 1992, according a recent
survey.
The January 2007 joint survey by the Tibet Plateau Institute of
Biology and the International Crane Foundation also found close to
32,000 Bar-headed Geese, more than double the population of 15
years ago, in Tibet.
At a time when most Asian water birds were declining, this
discovery was especially surprising, said the survey.
Unlike most of China's large wildlife, the Black-necked Cranes
live very close to people, descending from alpine meadows to winter
in farming areas of nearby valleys, according to the research
team.
"The farmlands in southern Tibet provide a perfect combination
of harvested grain fields for feeding and rivers for nighttime
roosting," said Professor Tsamchu Drolma from the Tibet Plateau
Institute of Biology and co-leader of the expedition.
The team of researchers covered more than 2,600 km over 11 days,
searching Lhasa, Yarlung, and Nyang River valleys and their
tributaries for the birds.
"We were delighted by how many the numbers have grown. The
creation of the Yarlung Zangbo River Middle Reaches Black-necked
Crane Nature Reserve along with better wildlife protection by the
Tibet Forestry Department and public awareness has made a big
difference for both of these species," said Dr. Mary Anne Bishop,
expedition leader from the International Crane Foundation.
Over 76 percent of the cranes and 48 percent of the geese were
found within boundaries of the new nature reserve, according to the
survey.
Another factor contributing to the recovery of the Black-necked
Crane may be warming conditions in Tibet, which lead to better
survival of the cranes, said experts.
But over the long-term, climate change could lead to reduced
water in Tibet and less wetland areas suitable for nesting cranes
and geese, they analyzed.
Temperatures have risen 0.42 Celsius degree each decade since
the 1980s, according to the Chinese Academy of Meteorological
Sciences.
The Black-necked Crane was the least known of the world's cranes
until recent decades. In 1993, its population was estimated at
about 5,600. The 2007 survey, combined with other recent studies,
indicated a world population of over 11,000.
The Black-necked Crane is the only one of the world's 15 crane
species that inhabits high altitude wetlands, with the species
mainly limited to the Qinghai-Tibetan Plateau and adjacent areas.
Smaller numbers also appear in Bhutan, India, and China's
Yunnan-Guizhou Plateau.
(Xinhua News Agency February 21, 2007)