Literature type: Scientific
Journal: Ecology and Evolution
Volume: 10 , Pages: 5281-5292.
Full reference: Pingyang, Z., Ye-ai, Z., Yonghong, X., Siqi, Z., Xinsheng, C., Feng, L., Zhengmiao, D., Hong, Z. & Wei, T. 2020. Hydrology-driven responses of herbivorous geese in relation to changes in food quantity and quality. Ecology and Evolution 10: 5281-5292. https://www.dx.doi.org/10.1002/ece3.6272
East Dongting Lake is a Ramsar site and a particularly important wintering ground for herbivorous geese along the East Asian‐Australasian Flyway. The operation of the Three Gorges Dam has changed the water regime and has a significant impact on wetland ecosystems downstream. We studied the responses of two sympatric herbivorous goose species, the Lesser white‐fronted goose Anser erythropus and Bean goose Anser fabalis, to habitat change by investigating their food conditions, habitat selection, and diet composition in the wintering periods of 2016/2017 and 2017/2018, which had early and late water recession, respectively. It was expected that the contrasting water regimes would result in different food conditions and geese responses. The results showed that the food quality and quantity differed significantly between winters. As responses to the high‐quantity/low‐quality food during 2016/2017, more geese switched to feeding on mudflat and exploited plants such as dicotyledons and moss. The tall swards of Carex spp. (dominant plants in the meadow) that developed during the first growing season decreased the food accessibility during the second growing season and hindered the exploitation of newly generated shoots by the geese, which was further confirmed by our clipping control experiment. Nearly all the geese chose to feed on meadow, and Carex spp. made up the majority of their diet in 2017/2018 when there was more low‐quantity/high‐quality food. Compared with the globally vulnerable Lesser white‐fronted geese, the larger‐sized Bean geese seemed to be less susceptible to winter food shortages and exhibited more stable responses. We concluded that the food quality–quantity condition was the external factor influencing the geese responses, while morphological and physiological traits could be the internal factors causing different responses between the two species. This study enhanced the understanding of the influence that habitat change exerts on herbivorous geese in their wintering site in the context of the Three Gorges Dam operation. We suggested that regulating hydrological regime was important in terms of wetland management and species conservation.
Literature type: Thesis
Language: Chinese (Mandarin) (In Chinese with English abstract and legends)Download:
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.
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.
Literature type: Scientific
Journal: Ecological Engineering
Volume: 88 , Pages: 90–98.
Full reference: Guan, L., Lei, J., Zuo, A., Zhang, H., Lei, G. & Wen, L. 2016. Optimizing the timing of water level recession for conservation of wintering geese in Dongting Lake, China. Ecological Engineering 88: 90–98. https://www.dx.doi.org/10.1016/j.ecoleng.2015.12.009
Habitat suitability and selection are key concepts in wildlife management, especially in protection of critical habitat and conservation of sensitive and endangered populations. In recent years, many approaches have been developed to link habitat suitability with animal occurrence and abundance. These approaches typically involve identifying existing habitats, defining habitat quality metrics, and estimating the association between animal occurrence/abundance and measured habitat metrics. In this study, we first tested whether we could measure habitat quality at Dongting Lake, China, one of the most important migratory waterbird wintering sites in the East Asian Flyway, for a group of Anatidae using metrics derived from the freely available multi-temporal MODIS vegetation index. The results showed that goose counts could be sufficiently modelled using mean winter season EVI (enhanced vegetation index) and habitat size computed from EVI time series and topographic wetness index (TWI). We then quantified the relationships between hydrological regimes and the habitat quality metrics. Our findings suggested that the timing of optimal water draw down should be early to mid October to ensure quality food sources for the wintering geese in Dongting Lake. The results have direct conservation implications as water recession timing is highly manageable through water flow regulation.
Literature type: Scientific
Journal: Journal of Ornithology
Volume: 155 , Pages: 707-712.
Full reference: Wang, X, Fox, A.D., Zhuang, X., Cao, L., Meng, F. & Cong, P. 2014. Shifting to an energy-poor diet for nitrogen? Not the case for wintering herbivorous Lesser White-fronted Geese in China Journal of Ornithology 155: 707-712. https://www.dx.doi.org/10.1007/s10336-014-1056-6
Geese often forage on mid-winter foods that fail to satisfy daily energy needs, but they may do so to acquire other nutrients, such as nitrogen. We tested thishypothesis by evaluating nitrogen budgets, namely thebalance of nitrogen income against expenditure, of winteringLesser White-fronted Geese Anser erythropus feedingat two sites within East Dongting Lake, China, where they could and could not balance daily energy budgets.Geese could balance nitrogen budgets in energy-rich habitats but were less able to do so in habitats where they failed to balance energy budgets. This study presents the first full nitrogen budget for a wintering goose species, and suggests that, rather than acting as a source of nitrogen, use of energy-poor but undisturbed habitats may represent a refuge from human disturbance at other habitats.
Literature type: Scientific
Volume: 155 , Pages: 576–592.
Full reference: Wang, W., Fox, A.D., Cong, P. & Cao, L. 2013. Food constraints explain the restricted distribution of wintering Lesser White-fronted Geese Anser erythropus in China. Ibis 155: 576–592. https://www.dx.doi.org/10.1111/ibi.12039
More than 90% of the Lesser White-fronted Geese Anser erythropus in the Eastern Palearctic flyway population winter at East Dongting Lake, China. To explain this restricted distribution and to understand better the winter feeding ecology and habitat requirements of this poorly known species, we assessed their food availability, diet and energy budgets at this site through two winters. Lesser White-fronted Geese maintained a positive energy budget when feeding on above-ground green production of Eleocharis and Alopecurus in recessional grasslands in autumn and spring to accumulate fat stores. Such food was severely depleted by late November and showed no growth in mid-winter. Geese fed on more extensive old-growth Carex sedge meadows in mid-winter where they were in energy deficit and depleted endogenous fat stores. Geese failed to accumulate autumn fat stores in one year when high water levels prevented the Geese from using recessional grassland feeding areas. Fat stores remained lower throughout that winter and Geese left for breeding areas later in spring than in the previous year, perhaps reflecting the need to gain threshold fat stores for migration. Sedge meadows are widespread at other Yangtze River floodplain wetlands, but recessional grasslands are rare and perhaps restricted to parts of East Dongting Lake, which would explain the highly localized distribution of Lesser White-fronted Geese in China and their heavy use of these habitats at this site. Sympathetic management of water tables is essential to maintain the recessional grasslands in the best condition for Geese. Regular depletion of fat stores whilst grazing sedge meadows in mid-winter also underlines the need to protect the species from unnecessary anthropogenic disturbances that enhance energy expenditure. The specialized diet of the Lesser White-fronted Goose may explain its highly restricted winter distribution and global rarity.
Literature type: Scientific
Volume: 100 , Pages: 5-11.
Full reference: Cong, P., Wang, W., Cao, L. & Fox, A.D 2012. Within-winter shifts in Lesser White-fronted Goose Anser erythropus distribution at East Dongting Lake, China Ardea 100: 5-11. https://www.dx.doi.org/10.5253/078.100.0103
Literature type: Scientific
Volume: 58 , Pages: 3-19.
Full reference: Fox, A.D., Lei, C., BArter, M., Rees, E.C., Hearn, R.D., Hao, C.P., Xin, W., Yong, Z., Tao, D.S. & Fang, S.X. 2008. The functional use of East Dongting Lake, China, by wintering geese. Wildfowl 58: 3-19.
Literature type: General
Journal: Bulletin of the Sendai Science Museum
Volume: no.7 1997 , Pages: 103-105.
Full reference: Iwabuchi, S., Gang, L., Young, J. & Yue, S.P. 1997. The short report on survey of Lesser White-fronted Geese at Dongting Lakes in China. Bulletin of the Sendai Science Museum: no.7 1997, 103-105.
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