Recently, more than 60,000 overwintering migratory birds were spotted in various parts of the Duchang water area of the Poyang Lake in east China's Jiangxi Province, jointly monitored by the Duchang Monitoring Station of the Poyang Lake Reserve and Duchang Migratory Bird Nature Reserve.
The Poyang Lake, the largest freshwater lake in China, is an important wintering ground for migratory birds on the East Asia-Australasia flyway. It is a seasonal lake, storing water in wet season and discharging water in dry season.
During the dry season, normally between October to March in the next year, a number of separate dish-shaped lakes form because of dropping water level. The marshes and mudflats of the lake area also gradually show up. Benthic animals, such as mussels and fish, and submerged plants in the dish-shaped lakes provide abundant food for the birds.
A dried dish-shaped lake in Duchang County, Jiangxi Province, September 23, 2022. (Photos: CFP)
Drought in Poyang Lake
Given the fact that, this year, the Poyang Lake suffers the most serious drought since 1961 due to the combined effects of high temperatures, reduced upstream water and less precipitation. The water level started to drop earlier in July. As of December 22, the water level at Xingzi Station, an iconic hydrological station at the Poyang Lake, dropped to 6.97 meters.
There should be 11 dish-shaped lakes in the Migratory Bird Nature Reserve in Duchang County, but eight of them dried up this year, according to a staff member from the reserve.
Migratory birds in the dish-shaped lake of Zhupao Mountain, Duchang County, Jiangxi Province, November 12, 2022.
Ecological water supply
Since September 19, Duchang County Migratory Bird Nature Reserve, under the guidance and support of provincial forestry departments, has implemented ecological water replenishment in the dish-shaped lake of Zhupao Mountain.
This lake is one of the most important dish-shaped lakes in Duchang water area of the Poyang Lake, said Li Yue, a staff member of the reserve. In previous years, it usually covers an area of nearly 67 hectares, but in September this year, the remaining water area is only 25 hectares. Compared with other dish-shaped lakes in the region, the lake of Zhupao Mountain is closer to the main channel of Kangshan River, which is convenient for the mechanical construction to transport water, Li said.
Currently, the area of the dish-shaped lake of Zhupao Mountain has gradually increased to about 57 hectares, and the water level is close to that in past years, Li added. Also, the grassland in the surrounding area has expanded and the population of benthic animals recovered. On December 8, more than 60,000 overwintering migratory birds were spotted in various parts of Duchang water area of the Poyang Lake.
However, is the number of migratory birds related to the ecological quality in the lake?
Migratory birds in the Poyang Lake, Hukou County, Jiangxi Province, December 15, 2022.
Other measures needed
Wang Wenjuan, an associate researcher on ornithology at Nanchang University, said that the ecology of Poyang Lake is not only about the number of birds, but also about the composition of bird species, namely species diversity and biological diversity, at the Poyang Lake Migratory Bird Research Conference in March this year.
Dai Nianhua, a researcher at the Jiangxi Academy of Science, has many years of experiences in animal and ecological protection in the province. "The Poyang Lake is the 'business card' of Jiangxi to the world, and it cannot be protected too much. However, other problems should not be ignored, such as how to sustainably protect the ecological environment of the Poyang Lake, how to coordinate ecological protection with the development of regional social economy, and how to solve the production and living problems of people in the lake area," he told China Daily in an interview.
To balance the relationship between water, grass, fish, birds, people and the lake, systematic coordination and scientific attention are required, none of which should be left out, he added.