Migratory Bird Sanctuaries along the Coast of Yellow Sea-Bohai Gulf of China

A threat in the region, albeit decreasing in severity, continues to be the loss to land reclamation of natural tidal flat areas that are important staging and feeding grounds of migratory waterbirds including some rare and endangered ones (Li et al., 2015). The area of tidal flats in the Yellow Sea has been drastically reduced since the 1950s, first due to conversion for aquaculture ponds and residential land and then due to creation of seawalls to create new arable lands and prevent shoreline retreat through erosion and defend human coastal activities and property from storms and natural hazards (Studds et al., 2017; Choi et al., 2018; Yim et al., 2018; Morres et al., 2019; IUCN, 2019). China has lost an estimated 70.2% of its tidal mudflats in the Yellow Sea since the 1950s (Murray et al., 2014). Since 2012, the rate of coastal land reclamation has slowed, but some reclamation continues. The total area of land claims from 2010-2020 is 64% less than the previous decade, however, there is now more reclaimed land than remaining intertidal habitat within this ecosystem (IUCN, 2023). The Chinese government announced a strict ban on commercial land reclamation in 2018 (Zhao, 2018). With the implementation of the national policy on coast wetland conservation (2018), and the national law on wetlands protection (2021), national authorities (Ministry of Natural Resources, Ministry of Environment Protection, and State Forestry and Grassland Administrations) are implementing strict monitoring and evaluation programs, with local governments responsible for any net loss of natural wetlands (IUCN Consultation, 2025).

Upper tidal flats are disproportionately important for the conservation of migratory shorebirds and thus their loss and degradation is having disproportionately severe impacts on many of the birds for which the property is inscribed (Mu & Wilcove, 2020, Cai et al 2024), especially the Critically Endangered Spoon-billed Sandpiper (Chang et al 2021, Sun et al 2025). Creation of supratidal high tide roost sites is not keeping pace with the requirements of the birds, for example at Tiaozini. Indeed of some concern is the fact that some of the Phase II sites don’t have any high tide roost site/area incorporated in the property (IUCN Consultation, 2025). Nevertheless, important work is being done to rectify this, for example, in Yalujiang, there is a restoration project, which is providing habitat for geese and ducks and high tide roosting sites for shore birds (IUCN Consultation, 2025).

Pollution from human waste, farming practices and industry is a threat to wildlife and human health in this coastal-marine ecosystem (IUCN, 2023). Mariculture, tourism, transportation, oil production, mining, salt harvesting, sea fishing and port construction and reclamation have developed intensively in recent years (Zhou et al., 2018) and each of these developments and activities brings with it a consequential threat of pollution and habitat loss for shorebirds.

Massive algal blooms, discharge of heavy metals and pesticides and the spread of alien invasive species have been observed in the past (Studds et al., 2017; Meng et al., 2019; IUCN, 2023). Heavy metals in sediments might cause serious and widespread environmental problems due to their toxicity, persistence and non-biodegradable nature (Meng et al., 2019). For example, Mercury residues are high in some coastal areas – possibly linked with chlor-alkali processes, and impacting migratory birds’ survival (Ma et al., 2024). This pollution significantly reduces prey availability and foraging opportunities for migratory birds (Studds et al., 2017). Microplastics are considered to be emerging pollutants of global concern in coastal and marine environments (Zhou et al., 2018). Monitoring of the macrozoobenthic food for shorebirds along the yellow sea from 2011 to 2016 showed declines of over 99% in the densities of the bivalve Potamocorbula laevis in Yalujiang, the major food here for birds such as Bar-tailed Godwits and Great Knots. This decline has largely been attributed to change in hydrological conditions and sediment composition due to port construction, run-off of agrochemicals from the extensive shoreline sea cucumber farms, and parasitic infection. The region is also subject to significant threats from oil spills, particularly in the Bohai Gulf (IUCN, 2023). There are some indications of further pollutants like DDT and triazophos posing a threat to the site's OUV, however the current status of their current loads is unknown (IUCN Consultation, 2025).

Ports in the region are large and continuing to expand. Eight Chinese ports are scheduled to handle the world’s largest vessels including in Qingdao, Tianjin, Caofeidian and Lianyungang, with more port developments south of Chongming Island (Hengsha Island). The Bohai Gulf is now considered the most concentrated area of port development worldwide. Although not within the inscribed World Heritage components, these port developments present a range of impacts including loss of natural habitat (direct and indirect – changes in hydrology and sediment movement), increased shipping disturbance, increased oil leaks and bilge discharge and risk of collisions (IUCN 2023). Jiangsu is one of the largest port Provinces along the east coast in China (Yu et al., 2019). The area is characterized by heavy marine traffic from and to major ports, creating some of the busiest sea routes in the world (IUCN, 2019).

A range of invasive alien species impact the site including alien fish species, some competing with native biota and/or impacting genetic integrity. The pathogen Lymphocystis virus has been introduced into this ecosystem and impacts flatfish. Reported occurrences of high pathogenicity avian influenza in migratory birds along the East Asian–Australasian Flyway (e.g. Meng et al. 2019; Takekawa et al. 2023) is also of some concern, although the extent of spread and occurrence within the component parts is not known. Mammals such as Rattus norvegicus predate the eggs of Streaked Shearwater, and infestations of Achyranthes japonica, a prickly plant, blocks the nesting burrows of Swinhoe’s Storm-petrels, and traps adults and young (IUCN 2023). However, the most concerning invasive species problem is Smooth Cord Grass (Spartina alterniflora), native to the Atlantic coast of North America. Vast areas were dominated by this invasive alien plant directly threatening the component areas despite eradication efforts (IUCN, 2024), however recent clearing efforts have shown some positive results, although regrowth is likely. Spread of Spartina has increased since the 2020 IUCN World Heritage Outlook assessment (IUCN Consultation, 2025). Where it occurs, Spartina alterniflora has changed the pattern of macrobenthos community distribution; accelerated the process of land cover formation; and can form a two-meter tall “green barrier” between the waterbirds and their food (IUCN, 2023). Various methods of Spartina alterniflora control have been tried but the species remains an issue. In 2022, the Chinese government issued the "Special Action Plan for the Prevention and Control of Spartina alterniflora (2022–2025)", aiming for nationwide eradication by 2025 (IUCN Consultation, 2025).

In 2024 the Chinese government began a spartina eradication programme along the entire China-coastline. The first round of clearing has been completed at least in Jiangsu Province. 2025 and 2026 will be a maintenance period. However, physical eradication has not been shown to be effective over the long-term due to the regeneration of the invasive species in some locations, and therefore the future threat is likely to remain relatively high (IUCN Consultation, 2025).

Upstream dams have changed the course of the rivers that drain into the yellow sea. The diminished volume of sediments reaching the coast, land reclamation (and erosion), ports and infrastructure for development projects, and artificial wetlands and channels found in the buffer zone are all indications of the large modification of the natural processes (IUCN, 2019; IUCN 2023; IUCN 2024). Sediment outflows from the two major rivers flowing into the Yellow Sea, the Yellow River and the Yangtze, have declined by more than 90% and 70% respectively over the last 100 years (Syvitski et al., 2009)
Coastal shallows also represent major foraging areas for the Critically Endangered Chinese sturgeon (Acipenser sinensis) in the Yangtze Estuary and upstream development has significantly impacted the survival of juvenile Chinese sturgeon residing in the estuary (Wang et al., 2018).

The national greening program (forest and grassland recovery program, desertification control program) has been successful in reducing soil erosion and there are indications of a decline in silt recharge to the sea (IUCN Consultation, 2025).

Poorly sited and designed wind farms will continue to lead to a decline in the quality of bird habitats, and the operation of wind turbines will cause direct mortality through collision to migratory birds, especially large flocks and larger birds (IUCN 2023). In addition the excessive duplication of tall pylons and power cables (because each company uses separate lines to channel its electricity into the grid) is a hazard to flying birds. The scale and numbers of such wind turbines is now much greater than in the 2020 IUCN World Heritage Outlook assessment and the southwest coast of the Yellow Sea, crucial for migratory birds, hosts the world’s largest concentration of operational offshore wind farms. The surge in installations is due, in part, to China's programme of subsidies. Research has shown that these wind farms are causing migratory birds to deviate from their normal and established migratory routes (IUCN Consultation, 2025; Lai, YC. et al, 2024). Zheng et al. (2024) analysed the spatial and temporal changes of the human-made characteristic areas that caused the change of the migration route of birds in the Yellow Sea from 2015 to 2022. The results show that the areas of impact zones in the study area on water of the Yellow Sea, during the last 8 years, increased 14 times, from 35.7 km2 to 506.3 km2. The areas of impact zones in the study area on land, during the last 8 years, increased almost two times, from 303.4 km2 to 544.2 km2, which also has a serious impact on the number of migratory birds.

Solar farm development is also occurring and expanding along the China coast in recent years (Wu, 2025). Mostly at the landward side of the coast (e.g. in aquaculture ponds), however there are plans to build farms on intertidal mudflats. Although these aquaculture ponds are not directly part of the WH site (mudflat) they provide high tide roosting and supplementary feeding opportunity for waterbirds. Plans to develop solar farms near and directly on tidal flats in the Yellow Sea e.g. on Dongling Mudflats in Rudong, Jiangsu is concerning. Dongling Mudflats is only second to Tiaozini in terms of its importance for Spoon-billed Sandpiper and Nordmann’s Greenshank. Installation of solar and wind farms on recently claimed tidal flats will also restrict the potential for those area to be restored as foraging or roosting sites. Yang et al. (2024) found that water-surface photovoltaic systems in teh Yangtze River decreased water temperature, dissolved oxygen saturation and uncovered area of the water surface, which caused a reduction in plankton species and individual density, altering the community composition. Water-surface photovoltaic systems also caused an overall decrease in bird diversity and changed bird community compositions. These findings suggested that water-surface photovoltaic systems have impacts on the water environment and ecology.

However it is promising that China recently issued a policy restricting (level of regulation/enforcement yet unknown) solar panel installation on tidal flats, and wind turbines should be put at least 30km off shore or in waters 30m deep (IUCN Consultation, 2025). Furthermore, monitoring of impacts of renewable energy infrastructure should be integral to permissions for development

Whilst climate change remains of utmost concern as a potentially existential threat to the site, there is already evidence that impacts are occurring. Reports at site level indicate evident climate change and rising sea level and shoreline erosion that is already impacting the inscribed components (IUCN Consultation, 2024). The wetlands are also at great risk from extreme weather events. Climate change is also impacting migratory habitats, patterns and seasonality across the wider East Asia-Australasia Flyway (EAAF) (EAAFP, 2018), within which the World Heritage property site acts a pivotal hub.

There is evidence of coastal erosion in northern part of Yanchen Wetlands. However, the key inter tidal wetlands (e.g., Tiaozini) have been growing both in space and in elevation due to marine currents transporting sediments from eroded coastal lines. Intertidal area in Yangtze river estuary, Yalu River Estuary and Yellow River Estuary have also been reported as growing by site management. Other components are not currently affected by sea level rise (Nan Dagang, and Snake Island) (IUCN Consultation, 2025).