Data Zone
Justification of Red List category
This species is one of many shorebirds in the East Asian–Australasian Flyway that is in steep decline. It breeds only in Far Eastern Russia, before migrating south through East Asia to winter (mostly) in Australia. There are a large number of threats impacting this species across this flyway, especially on passage where land reclamation for urban development, and invasion by Spartina cordgrass, has considerably reduced the area of suitable habitat available to it. On its breeding grounds, climate change may also be having an effect, but the impact of this threat on Siberian Sandplover is poorly known. Data suggest that these threats have driven population declines of 50–62% over the past three generations (2010–2023). If threats are not ameliorated, and declines do not slow or cease, then this species is at a relatively high risk of becoming extinct in the near-future. Accordingly it is listed as Endangered.
Population justification
Hansen et al. (2022) estimated that in 2016 there were approximately 180,000-275,000 ‘Lesser Sand Plovers’ in the East Asian-Australasian Flyway, although this total includes populations of C. atrifrons, which are (substantially) more numerous. Rogers et al. (2021) estimated that in Australia (where the majority of this species winters), numbers of mature individuals of mongolus and stegmanni were, respectively, 8,000-13,000 (best estimate 9,000) and 10,000-17,000 (best estimate 12,000), thus suggesting a total population of 18,000-30,000 (best estimate 21,000). Direct count data in Australia (from which the estimates above were largely derived) found at least c.20,000 birds with an extrapolated estimate of c.40,000 but not all of these birds will have been mature individuals, thus the total population in Australia used here follows Rogers et al. (2021). While this is considered a majority of the global population, it is unclear how many birds winter in eastern Indonesia and New Guinea (D. Rogers in litt. 2023), thus the upper bound of any global population estimate is also highly uncertain. Accepting that the Australian population does represent a majority, the global population is suspected to number 18,000-50,000 mature individuals, although this is highly uncertain.
Trend justification
All available data (almost entirely from the species’ wintering grounds in Australia) indicate a sharp reduction in the number of birds over the past three generations. Many of threats facing this species are imprecisely known (at least in terms of scale and relative contribution) and few have been mitigated or ameliorated. These threats are therefore projected to continue into the future. Using the data available to them (cited in parentheses), Rogers et al. (2021) estimated a rate of reduction of 56% over the past three generations, averaging trend data from: ?62% (Clemens et al. 2016), ?55% (Studds et al. 2017), ?56% (Clemens et al. 2019; Waterbird meta-analysis) and ?50% (Clemens et al. 2019; Generalised Additive Model to three generations). The generation length used by those authors is nearly identical to that used here (4.30 years vs. 4.44 years) hence these values are applicable here. Although these data are several years out of date, there has been no apparent recovery in population (R. Fuller in litt. 2023) and, precautionarily, these rates of decline are thought to be applicable for the three generations to 2023. A rapid recovery/rebound is considered unlikely, hence these rates are also applied to a moving window of 2012-2025. The rate of decline for the next three generations (2023-2036) is considered highly uncertain, but its suspected to be slightly slower due to the ceasing of land reclamation, and planned conservation action on Spartina cord grass. It is therefore set in the range of 30-49%.
In the breeding season, the species is confined to Russia. It may also breed on Attu Island, Alaska, United States of America (eBird 2023) although this is unconfirmed and from here (and more widely along the Alaskan coastline, mostly through the Aleutian Island Chain) it is for now considered only a passage migrant. From its breeding grounds, birds undergo an epic trans-equatorial migration south, after which almost all birds winter in Australia, with inconsistent numbers wintering in New Zealand. It has been recorded, or is assumed to occur, in almost all nation states between. Its exact migration routes remain improperly understood, owing to confusion in non-breeding plumage with C. atrifrons, from which knowledge has only recently allowed separation. Using photographs available on eBird (2023), Bakewell (2022) elucidated that C. mongolus takes a principally eastern migration route having never, for example, been recorded in Thailand or Peninsular Malaysia. Birds move south, chiefly coastally, through Russia, Japan and the Korean Peninsula (Republic of Korea [South Korea] and Democratic People's Republic of Korea [North Korea]), China (including Taiwan), the Philippines, eastern Borneo (Malaysia and Indonesia, but no records from Brunei), the Indonesian Archipelago (east of Bali), Timor-Leste [East Timor] and Papua New Guinea. Birds frequently pass through many Pacific states, including Fiji, Guam, the Federated States of Micronesia, the Marshall Islands, Northern Mariana Islands, Palau, Vanuatu, Solomon Islands, Nauru and New Caledonia. On occasion, birds may winter in these areas, but for the most part they are only passage migrants, with birds wintering further south. The same states are visited on the return northbound migration.
Behaviour This species is fully migratory, with two definable populations: mongolus and stegmanni both breed in Far Eastern Russia, migrating through the Korean Peninsula, Japan, China, the Greater Sundas and Lesser Sundas, mostly August-October, with birds then mostly wintering in Australia (and to an unknown extent in New Guinea and Wallacea).
Habitat Breeding In Siberia and the Commander (Komandorskiye) Islands the species breeds on mountains but also at sea-level, here inhabiting sand dunes and shingle along the coast (del Hoyo et al. 1996). Non-breeding The species is almost strictly coastal during the non-breeding season, preferring sandy beaches, mudflats of coastal bays and estuaries, sand-flats and dunes near the coast (del Hoyo et al. 1996), occasionally frequenting mangrove mudflats and feeding on exposed coral reefs (Solomon Islands, Pacific) (Cramp and Simmons 1983).
Diet Breeding The breeding diet of this species includes many beetles, weevils, fly larvae, stalk worms and crabs (del Hoyo et al. 1996). Non-breeding During the non-breeding season this species takes insects, crustaceans (such as crabs and amphipods), molluscs (particularly bivalves) and polycheate worms (del Hoyo et al. 1996).
Breeding site The nest of this species is a shallow scrape in bare sand or shingle (nesting pairs may often utilise cattle footprints), sometimes beside bushes and big stones, often amongst lichens and Drias (del Hoyo et al. 1996).
As for many shorebird species in the East Asian Australasian Flyway (EAAF), there is mounting direct and indirect evidence that this species is exposed to a myriad of threats at all stages of its migration cycle. On the breeding grounds, breeding productivity is thought to be reducing for this and other shorebird species due to climate change (Meltofte et al. 2007, Eikelenboom 2016), in particular due to interrupted trophic relationships and an increase in nest predation (Kubelka et al. 2018).
Perhaps the greatest concentration of threats occurs on passage. Since the early 2000s, land reclamation in China was considered a significant threat to this species (and all East Asian-Australasian Flyway shorebirds); astonishingly, the extent of reclaimed land along the Yellow Sea coastline now exceeds the extent of remaining intertidal mudflat (IUCN 2023), suggesting that this may have contributed greatly to declines in this species. The rate of habitat lost to land reclamation has slowed since a peak in c. 2013, in particular in recent years due to the promised near-ceasing of land reclamation in China in early 2018 (Melville 2018); however, recent satellite data suggests that the extent of intertidal mudflat has continue to decrease, in large part due to continued reclamations in the Korean Peninsula (IUCN 2023). Mudflats have also continued to degrade in suitability for this species and other shorebirds because of the invasive alien Spartina alterniflora cordgrass, which appears to be spreading; in recent (post 2020) years, this threat has probably driven greater declines than planned land reclamation. In addition to land reclamation, coastal development and a rapid increase in the human population along the coastline of the Yellow Sea has led to widespread degradation of mudflats and coastal habitats used by this species; IUCN (2023) (and references therein) cite the follows as additional drivers of mudflat loss and degradation: 'processes such as changes in sediment supply, loss of coastal vegetation associated with development...erosion, redistribution of sediments due to storms, and compaction and subsidence (sinking) caused by subsurface resource and groundwater extraction are also likely to be factors'. Offshore windfarms may have a so far unquantified impact on birds due to collisions (unlikely) and displacement and disturbance of feeding birds (more likely). Disturbance on mudflats by fishermen and others using the mudflats may also be reasonably considered a threat. Hunting is also possibly a significant threat impacting this species on its Russian breeding grounds (see, e.g., Klokov et al. 2023) and on passage (Gallo-Cajiao et al. 2020). In Australia, where most birds winter, Rogers et al. (2021) considered there to be 'no major threats with most birds [wintering] along sparsely populated coasts'.
Conservation Actions Underway
The main conservation actions currently being implemented to the benefit this species are on its migration routes, China is investing hundreds of millions of dollars to clear tidal mudflats of Spartina cordgrass, with the aim of eliminating 90% of it by 2025; locally, this has already been successful, for example at Chongming Dongtan National Nature Reserve (Stokstad 2023). The governments of China and South Korea have halted new projects that require or depend upon land reclamation, and across the Korean Peninsula the number of coastal wetlands has increased; moreover in China and South Korea, key areas for migratory shorebirds (including C. mongolus) have been identified and prioritised by government and two World Heritage nominations have been made on these grounds (IUCN 2023). Although data on scale or impact are sparse, IUCN (2023) consider that "support for coastal wetland conservation and wise-use appears to have increased over the last decade. There has been a substantial increase in the number of volunteer groups and NGOs helping to monitor the migrations of shorebirds and other waterbirds, as well as increased media coverage and special events, demonstrating enhanced awareness among coastal communities (see also EAAFP 2016). North Korea became a Party to the Ramsar Convention and joined the EAAF Partnership in 2018, demonstrating their commitment to the conservation of coastal wetlands.
In 2021, the 'Regional Flyway Initiative' (RFI) was set up by the Asian Development Bank, with technical support from BirdLife International, with the aim of protecting and restoring priority wetland ecosystems and the associated ecosystem services they provide in the East-Asian Australasian Flyway (EAAF), the most threatened flyway globally. The Initiative is slated for implementation in 10 East, South and Southeast Asian countries: Mongolia, China*, Bangladesh, Viet Nam*, Cambodia, Lao PDR, Philippines*, Thailand, Malaysia* and Indonesia*, many of which (those marked by *) are used by C. mongolus on northbound and southbound migrations between breeding and wintering areas. The RFI will mobilise large-scale financing to support the protection, sustainable management and restoration of at least 50 priority wetlands across ten Asian countries, with an initial financing commitment of $3 billion from the ADB (BirdLife International 2022). Over time, the RFI aims to enhance and expand the existing efforts in conserving and managing priority wetlands identified on the basis of supporting globally significant congregations of migratory waterbirds, and leverage on collaborative opportunities with stakeholders including national governments, civil society organizations, communities, regional organisations like the East Asian-Australasian Flyway Partnership.
Conservation Actions Proposed
The main action needed for this species and other EAAF shorebirds is the amelioration of threats on its migration, which are currently thought to be the principal cause of its decline. While progress has been over the past decade, all land reclamations need to be halted in all range states and remaining mudflats protected. China needs to implement its plan to eliminate 90+% of Spartina cordgrass. The discharge of toxic pollutants into coastal wetlands (especially where there are large shorebird congregations) needs to be controlled. Further degradation of mudflats needs to be stopped, including monitoring and preventing detrimental release of riverine sediments and responsible planning of offshore windfarms. In order to evaluate the success of the conservation actions listed above, robust monitoring is needed, preferably at all stages of its migration cycle, but especially in Australia where baseline data are readily available. Perhaps the greatest research gap is on the species' breeding grounds. It is unclear what threats are faced by the species while breeding (particularly whether breeding productivity is decreasing in the face of climate change and increased predation etc.). Continue to develop identification criteria to better inform the wintering distribution of this species, in particular determining how many birds winter in Wallacea and New Guinea.
Text account compilers
Berryman, A.
Contributors
Fuller, R. & Rogers, D.
Recommended citation
BirdLife International (2024) Species factsheet: Siberian Sandplover Charadrius mongolus. Downloaded from
https://datazone.birdlife.org/species/factsheet/siberian-sandplover-charadrius-mongolus on 26/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 26/12/2024.