Aerial photo taken on Aug. 20, 2020 shows the scenery of a wetland in Sanhuanpao National Nature Reserve in Fujin, northeast China's Heilongjiang Province. (Xinhua/Zhang Tao)

Aerial photo taken on Aug. 20, 2020 shows the scenery of a wetland in Sanhuanpao National Nature Reserve in Fujin, northeast China's Heilongjiang Province. (Xinhua/Zhang Tao)

Aerial photo taken on Aug. 20, 2020 shows the scenery of a wetland in Sanhuanpao National Nature Reserve in Fujin, northeast China's Heilongjiang Province. (Xinhua/Zhang Tao)

Aerial photo taken on Aug. 20, 2020 shows the scenery of the Fujin National Wetland Park in Fujin, northeast China's Heilongjiang Province. (Xinhua/Zhang Tao)

Aerial photo taken on Aug. 20, 2020 shows the scenery of the Fujin National Wetland Park in Fujin, northeast China's Heilongjiang Province. (Xinhua/Zhang Tao)

Aerial photo taken on Aug. 20, 2020 shows the scenery of the Fujin National Wetland Park in Fujin, northeast China's Heilongjiang Province. (Xinhua/Zhang Tao)

Aerial photo taken on Aug. 20, 2020 shows the scenery of a wetland in Sanhuanpao National Nature Reserve in Fujin, northeast China's Heilongjiang Province. (Xinhua/Zhang Tao)