|Scientific Name:||Anser cygnoides|
|Species Authority:||(Linnaeus, 1758)|
|Red List Category & Criteria:||Vulnerable A2bcd+3bcd+4cd ver 3.1|
|Reviewer/s:||Butchart, S. & Symes, A.|
|Contributor/s:||Barter, M., Cao, L., Fox, T., Goroshko, O., Lachmann, L., Mundkur, T. & Poyarkov, N.|
This species is listed as Vulnerable because it is suspected to be undergoing a rapid population decline owing to poor breeding success in recent years as a result of drought and considerable pressure from habitat loss, particularly owing to agricultural development, as well as unsustainable levels of hunting.
Anser cygnoides has its key breeding grounds in the border area between Russia, Mongolia and mainland China (BirdLife International 2001), with totals of 33,000 and 12,000 birds recorded in east Mongolia during surveys in 2003 (O. Goroshko in litt. 2003) and 2004 (Robson 2004) respectively. Other breeding sites include the lower reaches of the Amur river, north-western Sakhalin Island and Lake Khanka, Russia, western Mongolia and China. A poorly known population also appears to breed in eastern Kazakhstan, around Saisan-Lake and further east (L. Lachmann in litt. 2003), but its current status is unknown. In September 2005, six individuals were recorded in the Amu Darya River valley, c.125 km north-west of Turkmenabat in Turkmenistan, representing the first record of the species in this area (Marochkina and Rustamov 2008). Breeding is suspected in north-eastern North Korea. It winters in North Korea, South Korea, central China, and occasionally in Japan and Taiwan (China). Key wintering sites lie along the coast of Jiangsu and around the lakes of Poyang Hu and Dongting Hu in the Yangtze basin, China. Virtually the entire global population winters in the Yangtze floodplain (Zhang et al. 2011). Its population is estimated at 60,000-80,000 individuals, with significant declines in recent decades. However, a flock of 61,650 individuals was found at Shahu Lake (part of the Poyang Lake complex) in 2002 (Zhao Jing-Shen 2002), and in 2004/2005 totals, again numbering 61,000 individuals, were counted in the lower Yangtze Valley (Cao Lei et al. 2008). In January 2011, 87,544 were counted in a coordinated survey of all of the most important Yangtze River wetlands, with 25,502 at Neizhu and Waizhu Lakes, 21,000 at Hanchi Lake and 19,763 at Poyang Lake National Nature Reserve (Lei Jinyu per T. Fox and Cao Lei in litt. 2012). Declines appear to be continuing throughout Anhui province, for instance, with numbers wintering at Shengjin Lake declining from 10,000-20,000 birds in 2003-2006 to only c.1,000 by the winter of 2008/2009, probably owing to reductions in submerged vegetation (Zhang et al. 2011). The species's global wintering range has contracted dramatically in recent decades, and the species is now restricted to China, largely the Yangtze floodplain, where its range is perceived to be contracting rapidly (Cao Lei et al. 2010).
Native:China; Japan; Kazakhstan; Korea, Democratic People's Republic of; Korea, Republic of; Mongolia; Russian Federation
Vagrant:Lao People's Democratic Republic; Russian Federation; Taiwan, Province of China; Thailand; Turkmenistan; Uzbekistan
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The global population has been estimated at c.60,000-90,000 individuals (Liu Binsheng et al. 2002, Zhao Jisheng 2002, Lei Jinyu per T. Fox and Cao Lei in litt. 2012). Barter et al. (2004) and Barter (in prep.) counted 60,886 individuals in the Lower Yangtze Valley in 2004 and 61,178 individuals in 2005 (see also Barter in litt. 2007). In addition, the population in Korea has been estimated at c.50-1,000 individuals on migration and c.50-1,000 wintering individuals. The most recent coordinated survey of the Yangtze River wetlands in January 2011 found a total of 87,544 individuals (Lei Jinyu per T. Fox and Cao Lei in litt. 2012), suggesting an upwards revision of the upper boundary for the estimate of mature individuals to 90,000. However, this apparent increase is more likely the result of better count coverage than a genuine increase in population size (T. Fox and Cao Lei in litt. 2012).|
|Habitat and Ecology:||It breeds in wetlands in the steppe and forest-steppe zones, including river deltas, river valleys with meadows, the margins of brackish and freshwater lakes, and in mountainous areas along narrow, fast-flowing rivers. In winter, it occurs in lowland lakeside marshes, rice-fields, estuaries and tidal flats. Birds wintering at Shengjin Lake, China, have been observed feeding on below-ground tubers of Vallisneria asiatica and above-ground vegetation of sedges Carex spp. and canary grass Phalaris arundinacea (Fox et al. 2008). Recent research involving the satellite tagging of individuals has revealed that birds migrate in stages, stopping at a number of sites en route between breeding an wintering grounds (T. Mundkur in litt. 2006). Birds gather in large flocks to moult in late July prior to migration (O. Goroshko in litt. 2003).|
|Systems:||Terrestrial; Freshwater; Marine|
In Russia, the main threats are uncontrolled hunting, and the drainage and ploughing of breeding and moulting habitats, but disturbance by people and cattle also cause high levels of chick mortality (Goroshko 2004). In China, agricultural development at breeding grounds has resulted in wetland destruction and increased disturbance. Egg collection on Sanjiang plain (China), coupled with habitat loss to agricultural development, has probably resulted in a decline in the numbers of breeding Anatidae there of 90% in the last 30 years. Recent droughts on the breeding grounds have resulted in a number of years of poor recruitment (P. Nikolay in litt. 2007). The species is absent from many suitable areas probably as a result of disturbance caused by the use of motor-boats and other high-speed vessels as well as illegal hunting activity (Poyarkov 2005). Hunting of waterfowl remains a serious problem in many parts of China, and is reported to be increasingly so in Mongolia in recent years, where the traditional attitudes that inhibited wildfowl hunting are apparently being deliberately replaced with the notion that wildfowl are a useful food source (Poyarkov 2005). Its wetland wintering grounds are under increasing pressure from development and pollution. The availability of submerged vegetation at Shengjin Lake is being reduced by the expansion of intensive aquaculture, leading to a decline in feeding opportunities (Zhang et al. 2011). The Three Gorges Dam is also likely to have impacted the productivity of submerged vegetation at Shengjin Lake through changes in the hydrology, with other lakes in the Yangtze River basin likely to have been affected (Fox et al. 2008, Zhang et al. 2011). The species is becoming more concentrated at fewer key wintering localities, especially centred on Poyang Lake, which itself is subject to large between-year changes in hydrological conditions (resulting in inundated areas varying four-fold between years since c.2002) and has been proposed for damming (T. Fox and Cao Lei in litt. 2012). The concentration of birds at fewer sites in winter renders the population more susceptible to the impacts of pollution, disease, hunting, and the loss and degradation of habitat (T. Fox and Cao Lei in litt. 2012).
Conservation Actions Underway
CMS Appendix II. It is legally protected in Russia, Mongolia and South Korea and some provinces in China. Several important sites are protected in Russia, Mongolia and China. In 2006, breeding birds in eastern Mongolia were fitted with satellite transmitters to research winter movements as a component of avian influenza research (T. Mundkur in litt. 2006). The marking of birds with neck collars may produce further information on the species's migration strategies (e.g. Xu Wen-Bin 2008).
Conservation Actions Proposed
Survey the shores of Alexandra, Nikolay, Ul'banski and Tugurski bays (Russia). Study its decline and establish more protected areas in its breeding grounds. Protect breeding and moulting habitats in Russia. Protect the area around Chertovo lake and link it to the Orlik Wildlife Refuge (Russia). Expand the Khanka Lake Nature Reserve (Russia). Establish a protected area at the Han river estuary (South Korea). Regulate the hunting of all species of Anatidae in China. Reduce hunting at passage and wintering sites in Russia. Ensure legal protection in range states. Carry out research into the demographic consequences of forced diet changes in wintering populations of this species (Zhang et al. 2011). Study the impact of spreading aquaculture and changes in hydrology on the availability and productivity of submerged vegetation and formulate mitigation strategies (Zhang et al. 2011).
|Citation:||BirdLife International 2012. Anser cygnoides. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 May 2013.|
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