Yang Chunbing, director of the wetland management center of the county's forestry and grassland bureau, said many rare bird species have begun to choose Eryuan county as their wintering destination thanks to consistent work over time in its wetlands.

"Last year, national first- and second-class protected birds — the Oriental White Stork, Black Stork, Glossy Ibis and Greylag Goose were found wintering in Eryuan county for the first time," he said, noting that a total of seven Oriental white storks, known as the giant panda of birds, appeared in the county.

Yang said the county has a total wetland area of 4,590 hectares, including 2013 hectares of natural wetlands and more than 2,400 hectares of artificial wetlands.

"Ecological buffer zones totaling 926 hectares have been established along the banks of major rivers leading to Erhai Lake and around major lakes in the county. They not only purify the water but also restore and expand habitats for rare species," he said.

Another rare aquatic plant endemic to Southwest China, Ottelia acuminata, has also made a remarkable recovery in the county because of the improved aquatic environment.

Duan Conggui, an environmental protection engineer, said the plant requires extremely strict growth conditions. "It cannot survive in water that is even slightly polluted — either not clean enough or contains dissolved fertilizer," he said.