A Merganser duck, marked as endangered on the Red List of the International Union for Conservation of Nature, survives winter near a fast-flowing river in Wuyuan, Jiangxi province. [Photo by Tong Yu/China News Service/Provided to China Daily]

Ximaoli Lake is composed of 99 gully streams, including Maoli Lake and West Lake, one of the largest stream lakes and the second largest natural freshwater lake in Hunan. As a major node on the Yangtze River ecosystem, it is also an important transit station for north-south migratory birds.

He recalls that the local people followed a fishing operation rule which stipulated that fishing nets should only be employed during fishing season, and they stuck to the principle of "catching the big and releasing the small", adjusting the size of the apertures of the nets accordingly.

This sustainable fishing method gave the fish in Ximaoli Lake a chance to replenish itself and keep its ecological balance. Even in times of food shortage, the fishery resources remained sufficient.

But in 2008, when he returned from Switzerland where he had worked at Ramsar Convention Secretariat for five years, Lei was heartbroken and lamented on the declining environmental standards near his hometown－the indiscriminate discharge of pollutants from local agriculture that had caused the water in Ximaoli Lake to be downgraded from direct drinkable water to the current 'Class V"－"sticky and green" eutrophic water with a surplus of nitrogen, phosphorus and other elements.

"Air pollution is more visible and tangible to everyone, but drinking water safety caused by wetland pollution may be more serious," Lei said."Wetlands are the 'green infrastructural' response to climate change and a series of environmental problems."

Lei drew from his experience in ecological management and proposed to cut off the sources of pollution on the shore first. A joint defense mechanism was then established to regulate the aquaculture method through the Water Source Protection Law. When the pollution sources on the shore and in the water had been removed, wetland protection work was carried out to restore aquatic plants that would enhance the ability of the lake's own ecosystems to purify, fix and remove pollutants.