Desert oasis a lifeline for migratory birds
Protected Gansu wetlands a 'natural breeding ground' for black storks, other species
Mountain 'life source'
The water that makes this "airport" possible comes from much farther away.
Far upstream, snow, glaciers, permafrost and precipitation feed streams in the Qilian Mountains. Their runoff gathers into rivers and eventually flows into the Heihe River, sustaining ecosystems across the arid Hexi Corridor.
In an otherwise dry landscape, the Heihe River and its tributaries thread through a 41,200-hectare reserve in Zhangye, creating a mosaic of rivers, lakes, ponds, forests, grasslands and wetlands.
"The Qilian Mountains are the source of life for the Hexi Corridor and even Ejina," said Xu Erwen, director of the Gansu Qilian Mountain Water Conservation Forest Research Institute.
But the importance of the mountains goes beyond simply supplying water. "We have found that water has always been the key to understanding the Qilian Mountains," said Xu, who has studied the ecosystem for more than four decades.
The forests and grasslands of the mountains act as a giant "sponge", he said, and upstream water sustains the shallow waters, aquatic life and feeding grounds on which migratory birds depend.
The mountains' role also extends beyond water storage.
"The forests, grasslands and shrubs in the Qilian Mountains are not only the main components of water conservation, but also a 'pump' driving regional water-vapor circulation," Xu said.
But this system is not static. Xu's institute has maintained an ecological observation station in the Dayekou Basin of the Qilian Mountains for more than 30 years. Its observations show that temperatures there have risen by about 0.17 C every 10 years, Xu said.
Warming can accelerate glacier melting and permafrost thawing, but Xu cautioned against simply viewing this as beneficial to wetlands.
An ecosystem includes interconnected elements such as the cryosphere, water, forests and grasslands, he said. Changes in one section cannot simply be judged as good or bad for another.
What is clear, he said, is the importance of maintaining a stable water supply.
"There is no oasis without water. Without water, there is no life," Xu said, adding that ecological restoration and water conservation should be viewed over the long term rather than judged by one or two years of change.
