Portal to the Lesser White-fronted Goose

Literature type: Thesis

Language: Chinese (Mandarin) (In Chinese with English abstract and legends)

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Full reference: Ao, P. 2020. Migration strategies and conservation of two large-bodied Anatidae species in East Asia. , Master thesis, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. 105 pp.

Keywords: Satellite tracking, Migration strategy, Land use, Conservation status, China, Yangtze River, Dongting Lake, Poyang Lake, Shengjin Lake

Abstract:

The East Asian-Australasian Flyway (EAAF) is the most threatened flyway in the world. China is located in the center of the EAAF where more than one million Anatidae waterbirds winter every year. With the economic development in China, the loss of wetland has resulted in the declining waterfowl diversity and abundance. In order to conserve the waterfowl population and their habitats in China, it is urgent to define the distribution of key species, determine the distribution of key species and obtain the population estimates and historical changes, the location, land use and conservation status of key habitats. Based on satellite tracking, remote sensing data, field survey, ringing resightings, literature review and expert knowledge, we studied the Whooper Swan Cygnus cygnus, a common species, and the Lesser White-fronted Goose Anser erythropus, a global threatened species. The main results are: Satellite tracking, field survey, ringing resightings, literature review and expert knowledge found the East Asian populations of Whooper Swans summered from Yenisei River in the west to Anadyr River in the East, south to the border between China and Mongolia, and wintered in Xinjiang, Gansu, Qinghai, Beijing, middle and lower reaches of Yellow River in China, South Korea and Japan. The Whooper Swans that summered in central and western Mongolia, wintered in China; swans that summered in eastern Mongolia, wintered in China and South Korea; and swans that summered in Far East Russia, wintered in Japan. The East Asian population of Whooper Swans was estimated as 57,700, which increased compared to that in 2011 (42,000-47,000 individuals). Eight key wintering sites were found in Xinjiang, Qinghai, Henan and Shandong in China, six in the coastal and inland wetlands in South Korea and 14 in Hokkaido, Miyagi, and Iwate counties in Japan. Satellite tracking, ringing resightings and remote sensing data identified five wintering areas of Whooper Swans that summered in western Mongolia, namely, Xinjiang (12%), Gansu-Qinghai (16%), Henan-Shanxi-Shaanxi (51%), Beijing (2%), Shandong (19%), from west to east. The population growth may be related to the artificial food of two largest wintering areas (Henan-Shanxi-Shaanxi and Shandong). Tracked swans mainly used water in autumn, winter and summer (82% in autumn, 74% in winter and 62% in summer), and cultivated land (64%) in spring. 47% of the GPS fixes were in protected areas in summer, higher than those in winter (35%), spring (0%) and autumn (26%). The mean migration duration in spring was 21 days (range March 1 - April 15), and in autumn it was 14 days (range October 3 - November 13). At the same time, it is found that the conservation proportion in spring was 0. Therefore, it is suggested to strengthen the conservation of important stopover sites of the Whooper Swan in the bend of the Yellow River. The migration speed in spring was slower than that in autumn, due to more stopover sites and longer stopover duration in spring, which does not support the classic migration theory which claims that spring migration should be faster than autumn migration. Satellite tracking, field survey, literature review and expert knowledge found that the East Asian Lesser White-fronted Geese that summered from the Anabas River in the west to the Anadyr River in the east, and to the Far East Taiga in the south, wintered in the middle and lower Yangtze River in China, South Korea and Japan. The East Asian population of Lesser White-fronted Geese was estimated as 4,200, which declined compared to that in 2015 (16,000 individuals). East Dongting Lake in Hunan Province is the most important wintering site for Lesser White-fronted Geese, followed by Poyang Lake in Jiangxi Province and Caizi Lake in Anhui Province, and one key wintering site in Miyagi County in Japan. Satellite tracking and remote sensing data found that the major wintering sites of the tracked Lesser White-fronted Geese were Dongting Lake (50%), Poyang Lake (24%) and Shengjin Lake (18%) in China, and they summered in the Arctic tundra of Russia and Far East Taiga. The tracked geese mainly used cultivated land (52% in spring and 45% in autumn), tundra in summer (63%) and wetland (66%) in winter. 87% of the GPS fixes were in protected areas in winter, higher than that in spring (37%), autumn (28%) and summer (7%). The breeding area were located in the less populated Arctic tundra, although the proportion in protected area in summer was low. The Lesser White-fronted Goose was more concentrated in nature reserves during the wintering period, thus the conservation proportion in wintering area is high. Dongting Lake is the largest wintering site. However, its hydrological changes resulted in the decrease of food, degradation of habitats, and might have led to the decrease of population. Therefore, it is suggested to restore and maintain of the natural hydrological process of the wintering habitat of geese. At the same time, the conservation proportion in spring and autumn was relatively low, so it is suggested to strengthen the conserve of Northeast Plain in China, the main stopover sites in spring and autumn. The migration speed of Lesser White-fronted Geese in spring was slower than that in autumn, mainly due to the longer stopover duration in spring, which does not support the classic migration theory. Both the Whooper Swan and the Lesser White-fronted Goose are large-bodied Anatidae waterbirds in EAAF. The overall conservation proportion of the Lesser White-fronted Goose is higher than Whooper Swan, but the number decreased, which may be related to its unique requirement of food and habitat. The Lesser White-fronted Goose was affected by the decrease of food resources caused by the hydrological change of the Yangtze River, while the swan was affected by local conservation measures. Therefore, we suggest conservation strategies for these two species that faced different conservation challenge: the key point for the conservation of the Lesser White-fronted Geese is the restoration and maintenance of the natural hydrological process in the wintering area, and that of the Whooper Swan is to conserve and restore the key natural habitat and reduce the dependence of the swan on artificial food.