Location and General Description
The delta region that comprises the Yellow Sea saline meadows is situated along the east coast of China between the Changjiang (Yangtze) River and the rocky Shandong Peninsula. It is composed of recent alluvium, with deposits derived from both freshwater (river and lake) and marine environments. Mud flats are being deposited rapidly, due to silt deposition from the two large rivers – the Chanjiang and Huai He – that flow into the Yellow Sea in this part of China.
In prehistoric times, salt beds—shallow, intertidal meadow habitat—covered the coastal lowlands of the Huai River Delta and stretched to the marshlands at the mouth of the Yangtze River. For millennia, this region has been celebrated as "the land of fish and rice" because it has the capacity to supply protein and carbohydrates to a high-density human population. Indeed, Jiangsu Province is the most crowded in China with 619 people per km2 in 1987. For this reason, the area’s natural habitat has been largely converted for human use, although areas of salt marsh do remain today.
The region between the Huai He and Changjiang Rivers, is also the dividing point between the temperate and subtropical climatic zones. The region experiences humid to semi-humid monsoon climates, with an average annual precipitation between 800-1,200 millimeters. Typhoons often hit this region at the end of summer and in early fall. The average temperature in January is 2º- 4ºC and 26º - 29ºC in July.
Saline meadows are dominated by goosefoot (Suaeda salsa), and grasslands further inland (now separated by a seawall) are dominated by the grass, Imperata cylindrica. Grass and sedge marshes are an important component of the freshwater lakeside ecosystem further inland, but these have been almost completely extirpated by rice agriculture and fish aquaculture, as have the reed beds of Phragmites australis.
Grass and sedge marshes support "thatch grasses" such as Scirpus planiculmis, S. triqueter, Carex scabrifolia, Cortaderia celloana, and Panicum psilopodium. Saline marshes are dominated by goosefoot (Suaeda salsa) while freshwater wetlands support nearly single-species beds of the reed (Phragmites australis). Other important plant species in the freshwater habitats include pondweed (Potamogeton crispus), water milfoil (Myriophyllum spicatum), tape-grass (Ottelia alismoides), and buckbean (Nymphoides peltata.
Rare water birds over-winter in these coastal flats. They include Dalmatian pelican (Pelecanus crispus), black-faced spoonbill (Platalea minor), and little gull (Larus minor). Intertidal mudflats further offshore are an important breeding area for Saunders’ gull (Larus saundersi) which is seriously threatened and listed as vulnerable by BirdLife International (2000). The world’s largest breeding colony of Saunders’ gull is located here.
Many other migratory shorebirds visit these coastal marshes and mudflats en route to wintering grounds in tropical East Asia. Mudflats up to 5 km wide offer these birds a measure of protection from human disturbance.
Pere David’s deer (Elaphurus davidianus) and Chinese water deer (Hydropotes inermis) are rare mammals that are found in this ecoregion. Da Feng Nature Reserve includes some intact coastal grassland that provides critical habitat for Pere David’s deer. This is a captive breeding reserve, however, because this reddish colored, wide-hooved deer, the only species in its genus, no longer survives in the wild. The Chinese water deer has suffered sharp declines throughout China in recent years, due to hunting and habitat destruction.
Other species that occur within the Yellow Sea saline meadows include Chinese parrotbill (Paradoxornis heudei).
Yancheng Nature Reserve is an important wetland site located in this ecoregion. This 467 km2 coastal strip includes saline grassland and intertidal mudflats and provides breeding habitat for an estimated 40 percent of the remaining world population of red-crowned crane (Grus japonensis). Yencheng is a UNESCO MAB Reserve that covers 2,800 km2, of which about 20 percent consists of core area and buffer zone with relatively intact habitat. The remaining 80 percent is "transition area."
This region has some of the highest human densities in China, and large portions of the habitat have been altered for agriculture.
Types and Severity of Threats
Marine aquaculture is practiced in the coastal regions of this area. Commercial activities include rearing of shrimp (Porphyra spp.) and clams (Laminaria spp.). The coastal zone includes some habitat that is intact, albeit heavily exploited. Areas further inland have lost all traces of their natural vegetation. Salt production is also an important economic activity in this area.
Yancheng Reserve is currently threatened by shrimp farming and salt reclamation and is likely to be further threatened in the future by reclamation for industrial and recreational development.
Due to heavy silt loads in the Changjiang and Huai He Rivers, the delta is encroaching into the sea in some areas at a rate of 1 km every 60 years. Thus, there is some potential to protect new habitat in this area and to safeguard the processes of ecological succession. As coastal areas are converted to agriculture and industry, such efforts will be important to maintain the variety of habitats necessary to sustain the region’s biological diversity.
Justification of Ecoregion Delineation
This ecoregion consists of the Huai He Delta and the coast of Hangzhou Bay. The boundary is derived from saline meadow (67) on the CVMCC (1979) Vegetation Map of China.
BirdLife International. 2000. Threatened birds of the world. Lynx Editions and BirdLife International. Barcelona and Cambridge, UK.
Chinese Vegetation Map Compilation Committee (CVMCC). 1979. Vegetation map of China. Map (1:10,000,000). Science Press, Beijing.
MacKinnon, J. and K. Phillipps. 2000. A Field Guide to the Birds of China. Oxford University Press, New York.
MacKinnon, J., M. Sha, C. Cheung, G. Carey, Z. Xiang, and D. Melville. 1996. A biodiversity review of China. Worldwide Fund for Nature (WWF) International, Hong Kong.
Ramsar Convention on Wetlands. Retrieved (2000) from: www.ramsar.org
United Nations Educational, Scientific, and Cultural Organization. Retrieved (2000) from: http://www.unesco.org
Prepared by: Chris Carpenter
Reviewed by: In process