Wetland biodiversity

 

1 Current situation and distribution of wetlands

2 The biodiversity of Chian¡¯s inland wetlands

3 Importance of China¡¯s wetlands in worldwide rare waterfowl protection

4 Chinese wetlands listed in the Inventory of Internationally Important Wetlands

5 Destruction of Chinese wetlands

6 Protection and restoration of Chinese wetlands

 

1 Current situation and distribution of wetlands

       (1) Current situation

       As defined in the ¡°Wetland Convention¡± a wetland is an ¡°Area of marsh, fen, peatland or water, whether natural of artificial, permanent or temporary, with water that is static, flowing, fresh, brackish or salt, including areas of marine water, the depth of which at low tide does not exceed six meters.¡± Therefore, wetlands include not only mires, bogs, and mudflats, but also rivers, lakes, reservoirs, paddy fields, and marine areas with a depth of less than 6m at low tide.

       China has a natural wetland area of 25 million ha, including mires (11 million ha), lakes (12 million ha), mudflats and salt marshes (2.1 million ha), as well as artificial wetlands and paddy fields (38 million ha), giving a total of 63 million ha. Still excluded, however, are rivers and streams, reservoirs, ponds, and marine areas with a low tide depth of less than 6m. In terms of types, China has not only every kind of wetland defined in the ¡°Wetland Convention¡±, but also a unique wetland on the Qingzang Plateau.

       (2) Distribution of inland wetlands in China

       Wetlands are distributed extensively in all regions of China, from the northernmost bank of the Heilongjiang River in the north to Hainan Island and the islands of the South China Sea in the south; from the coastline in the east to the arid Northwest Region. They even exist in the Pamirs. The great differences of such natural conditions in these different zones give China¡¯s wetlands distinctive characteristics.

       Bordering the Pacific in the east, the climate of eastern China is humid and warm, with high precipitation resulting in numerous lakes and a high density of aquatic systems, which contribute to the extensive distribution of large-scale wetlands. The total area of wetlands in eastern China comprises three-fifth of the country total. There are many types of wetlands, from north to south.

       In the cold temperate and temperate Daxing¡¯anling, Xiaoxing¡¯anling and Changbaishan Mountains with a humid climate, wetlands are diverse and widespread. Vast areas of sedge marshes are distributed in the Sanjiang Plain and reed marshes cover the Songnen Plain.

       In the humid/semihumid warm-temperate and subtropics of the North China Plain, Huaihe Plain and the Mid-Lower Yangtze River Plain, numerous lakes and dense river systems have created large areas of reed and Miscanthas saccharifolrus wetlands. There are various Potamogeton communities in shallow lakeside wetlands.

       In the humid, subtropical, the hilly region to the south of the Yangtze River, and Yungui Plateau, there are small, scattered, wetlands, because of the influence of the hilly landform. There are moss bogs in depressions in mountains, reed wetlands around the edge of lakes, and the endemic Ottelia yunanensis wetlands.

       In the humid, tropical, mountain valleys of southwestern Yunnan Province and in the coastal regions of Guangdong and Hainan Provinces, scattered reed swamps occur as small patches. Glyptostrobus pensilis forests grow on the delta, and mangrove forests line bays.

       The western part of China includes the Mongolia-Xinjiang and Qingzang Plateaus where the climate is either arid or semi-arid with low precipitation levels. Here, wetlands only exist in depressions, overflowing zones of piedmont groundwater, and in lake depressions. The various types of wetland are quite simple, e. g., reed wetlands, sedge marshes and inland saltmarshes.

       In elevated areas above 3,400 m in the Qingzang Plateau, there are many lakes and depressions, and many great rivers also originate here. The elevated cold climate results in a frozen earth. Modern glaciers provide abundant melt water. These favour the development of wetlands. For example, there are vast area of mires in the source areas of the Yangtze River, Yellow River, Yarlung Zangbo and Nujiang Rivers. In the Zoige Plateau of northern Sichuan, especially, mires occupy a vast area, being the most extensive such highland mires in the country. Nevertheless, mire types are very simple. Here, there are herbaceous marshes such as the endemic Carex mulensis marsh and Kobresia-Carex marsh with ridge-net shaped herb hillocks.

       The content of this section is limited to inland wetlands.

2 The biodiversity of Chian¡¯s inland wetlands

       The vast territory of China with complex natural conditions result in an extraordinary abundance of wetland ecosystems. China has nearly all 35 categories of wetlands listed in the Ramsar classification and inventory system, i. e., 12 coastal, 14 inland, and 9 man-made wetlands.

       Animals are extremely diverse in China¡¯s wetlands. There are 65 known species of wetland animals comprising 13% of the country¡¯s total. Wetland birds comprise 300 species (26%), reptiles 50 species (13%), amphibians 45 species (16%) and fish 1,040 species (37%) of the country¡¯s total, or more than 8% of the world total of freshwater fish.

       There are 1,548 species of higher plants in China¡¯s wetlands, including 1,332 species of angiosperms, 10 species of gymnosperms, 39 species of pteridophytes, and 167 species of bryophytes.

       There are many valuable, endangered, rare and endemic species, e. g., Lipotes vexillifer, Psephurus gladius and Myxocyprinus asiaticus are endangered and endemic to the Changjiang Basin. Ciconia nigra, Grus japonensis, Grus antigone, G. nigricollis and Alligator sinensis are all rare and endangered species. Of the 57 endangered species of birds in Asia, China has 31 species, i. e., 54%. China¡¯s wetlands have 9 species of cranes making up 23% of the world total of 15 species. There are about 100 species of endangered species of higher plants in Chinese wetlands. For example, Glyptostrofus pensilis now only occurs as scattered plants in Guangdong, Guangxi and Fujian Provinces. Mangroves are unique coastal wetland plants, and have been severely destroyed, so that only less than 20,000 ha survive today.

       At present, the genetic diversity of wetland species in China has been little studied. Some researches have focused only on wild rice and some endangered species.

3 Importance of China¡¯s wetlands in worldwide rare waterfowl protection

       Wetlands are the breeding grounds, winter habitats, and migration points of waterfowl. The special natural conditions and geographical location of China¡¯s wetlands have resulted in abundant species of waterfowl and play a special role in worldwide waterfowl protection.

       (1) Abundant waterfowl species

       According to preliminary statistics, there are 1,244 species of birds in China, 257 of which are waterfowl, that is, 20.6% of the total number of birds. These include 125 species, 50 genera and 15 families of natatorial birds, and 132 species, 54 genera and 14 families of wading birds. There are four endemic species, i. e., Grus nigriollis, Gorsachius magnificus, Mergus squamatus and Thalasseus zimmermanni. There are many rare and endangered species in Chinese wetlands. These include 11 species of national first-grade protected birds, such as Ciconia ciconia, and 22 species of national second-grade protected birds, such as Egretta eulophotes. Many waterfowl are under international protection. Of 227 species of protected birds listed in the ¡°Agreement to Protect Migratory Birds and their Habitats in China and Japan¡±, 147 are waterfowl comprising 24 wading species and 62 natatorial species. Of 81 species listed in the ¡°Agreement to Protect Migratory Birds and their Habitats in China and Australia¡±, 70 are waterfowl comprising 49 wading and 21 natatorial species. In addition, China¡¯s wetlands support many global rare and endangered species. For example, 9 of the 15 species of Gruidae in the world. These are Grus nigriollis, G. leurogeranus, G. vipio, G. monachas, G. japonensis, G. grus, G. antigone, G. canandensis and Anthropoides virgo. China¡¯s wetlands support 3 of the 5 species of swan in the world. They are Cygnus cygnus, C. columbianus and C. olor.

       (2) Important habitats for worldwide waterfowl

       a. The major wintering habitats of waterfowl in the Eastern Hemisphere

       A number of cranes, such as the Red-crowned crane (G. japonensis), Siberian crane (G. leurogeranus), White-napped crane (G. vipio), Hooded crane (G. monacha) and the Grey crane (G. grus), from Russia, Japan, Korea and Northern China, come to the Yancheng Wetland in Jiangsu Province every year to overwinter. Of these, the Red-crowned crane is the most numerous, totalling more than 600 individuals. This wetland is one of the major wintering habitats of the Red-crowned Crane in the world. Poyang Lake Wetland is another major wintering habitat for the Siberian crane in the world, between 2,000~3,000 individuals from various places come here to overwinter annually.

       Coastal wetlands are key habitats for wintering swans. For example, the Rongcheng Wetlands in Shandong Province support about 5,000 swans, while Chongming Island in Shanghai supports between 3,000~5,000. Red-beak gulls (Larus ridibundus) and Silvery gulls (L. argentatus) come annually from Russia to Yunnan Province to overwinter.

       Hongze Lake in Jiangsu Province is the most concentrated wintering area of bustards (Otis tarda) in the world. Every year, between 5,000~7,000 of them come in October from Russia, Mongolia, Korea and Northern China.

       b. Major breeding grounds for worldwide waterfowl

       Sanjiang Plain and Songnen Plain in the northeast are breeding areas of the Red-crowned crane with Panjin as the southern extremity of the area.

       Bayinbuluke Wetland, between 2,300~2,800 m above sea level in Tianshan Mountains in Xingjiang Autonomous Region, attracts between 5,000~8,000 swans every summer from various places to breed. It is one of the largest swan breeding habitats in the world and supports all three species of swan that occur in China.

       The Red-beaked diving duck (Netta rufina) and other species of duck from India breed along the reaches of the Tarim River in summer.

       c. ¡°Transfer stations¡± along the migration paths of migratory birds between the Southern and Northern Hemispheres

       Coastal wetlands and islands are habitats and resting sites for waders (Charadriformes) and gulls (Lariformes) migrating from the western Pacific Ocean, Australia and New Zealand, to the north. Some waterfowl rest in China¡¯s coastal wetlands before they fly to their Siberian breeding grounds. In autumn, they return from the north heading for Australia and New Zealand. Chongming Island supports 39 species of waterfowl listed in the ¡°Agreement to Protect Migratory Birds in China and Australia¡± and individual numbers in summer reach the hundreds of thousands. The mangrove forest in Futian, Shenzhen, supports more than ten species of waterfowl, such as Charadris asiaticus, which migrates in spring from Australia to Siberia, and back in autumn from Siberia to Australia.

4 Chinese wetlands listed in the Inventory of Internationally Important Wetlands

       Six of the numerous Chinese wetlands have been listed in the Inventory of Internationally Important Wetlands:

       Poyang Lake Wetlands. This is situated in the subtropical zone with an area of 224,000 ha and supports abundant waterfowl comprising 150 species and several hundred thousand individuals in winter. For example, in 1981, there were more than 0.8 million birds present, including 2,890 Siberian cranes, the largest population of this species in the world, and 3,940 swans (C. columbianus).

       The Eastern Dongting Lakes Wetlands. This covers 0.19 million ha and supports 153 species of birds concluding 103 waterfowl. Of these, 39 species are internationally protected and 32 are under national protection. With 10 million winter visitors, it is one of the largest bird habitats in Asia. In addition, some national protected species such as Lipotes vexllifer, Black finless porpoise and Neofelis nebulosa live in such lakes.

       Zhalong Wetland. This lies in the northern part of the Songnen Plain in the temperate zone and covers 210,000 ha. The extensive reed wetland supports more than 230 species of birds including more than 120 waterfowl dominated by 6 species of cranes, i. e., Red-crowned crane, Siberian crane, White-napped crane, Hooded crane, Grey crane and Anthropoides virgo.

       Xianghai Wetland. This lies in the southern part of the Songnen Plain and covers more than 100,000 ha. The extensive reed wetland supports more than 260 species of birds, including 112 waterfowl. There are 6 species of crane and representatives of the Ardeidae, Anseriformes and Lariformes.

       The Qinghai Bird Island Wetland. This lies at 3,185 m above sea level in the northeastern part of the Qingzang Plateau and covers some 54,000 ha. It supports 162 species of birds, dominated by the Anseriformes. There are 4 species of macro-waterfowl, i. e., Larus brunnicephalus, L. ichthyaetus, Anser indicus and Phalacrocorax carbo. A survey in 1991 showed that the populations of these were 18,500,9,000,7,000 and 5,500, respectively. There are also thousands of Tadorna ferruginea and Athya sp..

       The Hainan Dongzhai Port Wetland. This is situated in the east of Hainan Province, and covers 5,400 ha. There are 29 species, in 15 families, of mangroves, such as Rhizophora stylosa, Rhizophora gymnorrhiza and Bruguiera sexangula. Other plants, such as Pandanus fectorinus and Calaphyllum inophyllum are less common. There are also many waterfowl, e.g., Ardea cinerea, Egretta alba, Egretta intermedia, Fulica atra and Tringa lotanus.

5 Destruction of Chinese wetlands

       Wetlands are resources of land, life, water, minerals and tourism. Long-term human activity has seen wetlands reclaimed, polluted, silted-up and decreasing in terms of area and species, i. e., all wetlands have been destroyed to different extents.

       Agricultural reclamation and urbanization are key factors in wetland declines. The wetlands of the Pearl River delta and the middle and lower reaches of the Yangtze River have been reclaimed for paddy fields since ancient times. The Sanjiang Plain in northeast China is now under reclamation. As much as 1 million ha of coastal mudflats have been reclaimed during the last 40 years, and equals 50% of the total area of coastal wetlands. The engineering practice of dyking mudflats to make land has reduced the area of coastal wetlands at a rate of more than 20,000 ha per year. Another estimate is that in the 30 years between 1950 and 1980, the number of China¡¯s natural lakes decreased from 2,800 to 2,350 with an area loss of 11%. Some lakes adjacent to cities have practically lost their ecological functions owing to serious pollution and eutrophication.

       Loss of water and erosion have caused the deposition of silt in riverbeds and lakes and reduced wetland area. At the beginning of the century, Dong Ting Lake was once 4,350 km2 in area, and was the largest freshwater lake of China. Due to the deposit of 120 millions m3 silt every year, this lake has been reduced to 2,500 km2.

       The utilization of water resources in wetlands are not rational in some regions, for example, the wetland area in Bositeng Lake was decreased by 300 km2 from 1958 to 1988. Industrial development and pollution has contributed to the extinction of some species, for example, the Round sundew Drosera rotundifolia cannot be found in the bogs of the Xiao Hinggan Ling Mountains now.

       Excessive utilization and unreasonable exploitation of wetland¡¯s biological resources have seriously destroyed the ecosystem balance and biodiversity of the wetland, so that biomass has also decreased.

       China is a developing country. From the beginning of the open-door policy, its economy has developed rapidly. Such fast production requires many resources and raw materials. Wetlands have inevitably suffered losses and threats. This is particularly serious in eastern coastal areas, rivermouths, banks of major rivers, floodplains and around large lakes. These places possess key elements for developing economies and have the superiority of territory, communication, and water and biological resources. Many of them abound in oil, natural gas and various minerals. Such circumstances make them hotspots for China¡¯s development. China also has a great number of people. The multiplication in population is accompanied by an increase in consumption of resources and damage to wetlands.

6 Protection and restoration of Chinese wetlands

       The Chinese government pays great attention to the protection, utilization and research of wetlands. Since the 1950s, some research institutes and higher education institutions have been studying these problems. A series of articles are available on wetland protection. Each province and city has stipulated some local laws and regulations, including a ban on hunting and fishing in some areas. These measures have played an important role in the protection of wetland resources. In order to enlarge China¡¯s function and global influence in the sphere of nature protection, more information and experience in the protection and utilization of waterfowl and wetlands abroad is needed, further steps to participate in international actions for the protection of wetland should be taken and raise the level of China in this field. According to the decision of the State Council, China officially joined the ¡°Convention on Wetlands¡± on 31 July 1992.

       The Ministry of Forestry predecessor of SFA organizes and co-ordinates the implementation of the Convention. Subsequently, many actions have been undertaken, such as establishment of some organizations and departments for protection and management of wetlands, propaganda and educational works, personnel training, the delimitation of wilderness areas, engineering projects in wetlands, scientific research, and co-operation with other countries. China has achieved considerable success in this field. Owing to the joint efforts of the departments and organizations concerned, a small number of damaged wetlands have been restored and reconstructed in recent years.