General Information

    1.1 Biogeographical Province of Dongzhaigang Nature Reserve

    The Dongzhaigang National Nature Reserve is located in Dongzhaigang Bay bordering the administrative regions of Qiongshan City and Wenchang City, in north eastern Hainan Province. The area trans-bounds the tropical and sub-tropical zones of southern China and has a correspondingly diverse transitional fauna and flora with the southern sub-tropical species dominant. The transitional climatic and hydrological conditions, specific topographic features (estuarine ecosystems) and its rich biodiversity ensure its global significance as a wetland of international importance. Its relatively large area of mangrove forest and wide inter-tidal sand- and mudflats provide migratory water birds and fish with rich feeding grounds and breeding habitats.

    1.2 Climatic and Geographic Conditions

    1.2.1 Climate

    The Dongzhaigang National Nature Reserve has a tropical monsoon marine climate with an average annual rainfall of 1676.4 mm and a mean annual temperature of 23.3-23.8^oC. The mean temperature in July is 28.4^oC and in January 17.1^oC. The rainy season starts in early May and ends in late October. The region is usually affected by typhoons during the summer months.

    1.2.2 Hydrology

   Four rivers enter into the Dongzhaigang Bay, these are Yanzhou River,Sanjiang River, Yanfeng River and Xi River, with a total water discharge of 700 million cubic meters. During the rainy season, the four rivers carry large amount of silts which are largely deposited within the bay to create the extensive inter-tidal mudflats. It is the mudflats that provide a suitable environment for mangrove growth in this area.

    The seawater temperature is high due to the low latitude and warm winter currents that affect the area. Within the Dongzhaigang estuary, the annual mean temperature of the sea water is 25.4^oC, while the highest mean water temperature from the May to July is 31.5^oC and the lowest in January is 17.7^oC.

    Salinity within the estuary ranges from 9.31‰ to 34.4‰ in different parts of the estuary and at different states of the tide. The salinities in the dry season are higher than those in the rainy season. Mangroves are known to tolerate a wide range of water salinities and can grow in coastal areas and along rivers with salinities between 2.17-34.5‰.

   The Dongzhaigang Estuary has irregular semi-diurnal tides with an average high tide elevation of 2.09 meters and low tide elevation of 1.19 meters. The maximum tidal range is 1.8 meters while the average tidal range is 0.89 meters.

    1.2.3 Geology

    The bed rock of the Dongzhaigang Estuary has formed over a long geological period and is therefore quite rigid. The estuary has a dense network of tidal canals and a deep soil layer.

    1.2.4 Topography

   The Dongzhaigang Estuary has an irregular rectangle shape with a south-north orientation. It is the largest bay in Hainan Province with a total area of nearly 100 square kilometers. The estuary is thought to have formed due to subsidence of the coastal zone in northeast Hainan during the Qiongzhou Earthquake of 1605. The estuary forms a nearly closed lagoon having only two narrow channels connected it to the South China Sea in the north. Beigang Island, situated at the mouth between the two channels, is large enough to block the effects of strong storms from the South China Sea. The eastern side of the estuary consists of an alluvial plain and the western side is bordered by low hills.

    1.2.5 Soils

    The base rocks in this area are mainly basalt and olive basalt and these are the origin of overlying soils. Typical acid red soils have been developed under the sub-tropical and tropical climate. The soil layer is generally between 1 and 1.5 meter thick and the acidity is pH 5-6.The soils under the mangroves are mainly saline marsh soils.

    1.3 Biological resources

    1.3.1 Flora

    The major vegetation community in this area is mangrove and its associated salt-tolerant species termed mangrove associates. Historically Dongzhaigang Estuary was more forested than it is today, in the early 1950s 3,414 ha of mangrove forest was recorded, this was reduced to 1,773 ha by the 1960s and 1970s due to intensive agricultural reclamation and mangrove forestry operations.

    Through annual replanting programmes and the cessation of logging operations the area of mangrove forest today stands at 2,006 ha.

    Dongzhaigang mangrove forest has 26 "true" mangrove species belonging to 12 families, and 40 semi-mangrove and mangrove-associated species belonging to 22 families. The rarer species include Nipa fruticans, Lumnitzera littorea, Sonneratia hainanensis, S. ovata, S. paracaseolaris, Xylocarpus granatum, Rhizophora apiculata and Acrostichum speciosum, of which S. hainanensis is believed to be an endemic species restricted to Hainan Island. In addition, N. fruticans, L. littorea, S. hainanensis, S. paracaseolaris and X. granatum have been listed in the China Plant Red Book (For a comprehensive plant list refer to Appendix 2).

   The major mangrove communities are outlined below:

   (1) Bruquiera gymnorrhiza community

    It appears dark green with a regular crown canopy. The trees are 4-8 meter tall with a diameter at breast height (dbh) of 8-15cm. Mainly distributed in the upper reaches of Sanjiangxi and lower reaches of Yanfengdonghe.

    (2) Bruquiera sexangula community

    It appears emerald green with a regular crown canopy. The trees are 8-15 meter tall with a dbh of 20-32cm. Mainly distributed in front of Yanfenghe Harbor Village, Longwei Village and Qukouyunlu Village.

    (3) Ceriops tagal community

    It appears yellow green with a lot of branches. Forms almost a pure single-species forest. The trees are 1-3 meter tall with base diameters of 8-15cm. Large areas of this community are situated to the south of the core area at Tashi and at the river mouth of Yanfengdonghe.

    (4) Avicennia marina community

    The community appears silver-grey green with trees of between 2-4 meter tall. The base diameter is 10-15cm. A. marina is the main pioneer species found predominantly along the accreting front edge of the mangrove and beside tidal channels. It is a highly adaptable species and the crown can be partly or totally submerged during high tides.

    (5) Kandelia candel community

     K. candel is a pioneer species which grows along the front edge of the forest in the accretion zone. The community appears yellow green and the trees are 3-4 meter tall with a dbh of 5-10 cm.

    (6) Rhizophora stylosa community

    R. stylosa is a pioneer species and usually grows along the accreting front edge of the mangroves at the interface with the mudflats. The community appears dark green forming a dense and regular forest. The trees are 2-5 meter tall. It is distributed in the mudflats from the core area Tashi to Dalin.

    (7) Nipa fruticans community
It normally grows in the high tidal zones near the mainland. This community is easily identified as it consists of dwarf green palm forest. The palms are 3-4 meter high. It is naturally distributed in the experimental zone near Lonshuyuan Village and Shangyuan Village.

    (8) Acrostichum aureum community

    A. aureum is a fern that normally grows in the drier landward margins of the mangrove forest. The community appears brown green and is 0.4-1 meter high. It is found at Hegang, Sanjianghe and in the upper reaches of Yanfengdonghe.

    (9) Aegiceras corniculatum community

     A. corniculatum is another pioneer mangrove species. It sprouts easily and usually grows along the banks of the estuary and on the seaward edge of the mangrove forest, especially in previously cleared mangrove areas. The community appears yellow-green. The shrubs are around 1 meter tall with a regular crown and usually grow in dense clusters.

    (10) Lumnitzera racemosa community

    This grows only in areas reached by the spring tides. The community appears pale green and the plants are 1-3 meter high with a base diameter of 5-12 centimeters.

    (11) Rhizophora stylosa+Ceriops tagal community

     This community grows in the mid- to high tidal mudflat. R. stylosa trees are 1.5-3 meter tall with C. tagal forming dense stands of 1-2.5 meter tall.

    (12) Ceriops tagal+Aegiceras corniculatum community

    This community is restricted to the solid sand clay areas and appears yellow green. The average height of the plants is 1 meter. C. tagal grows densely with a lot of seedlings whilst A. corniculatum is relatively dispersed. This community is distributed in Shatushi and Gongxi.

    (13) Sonneratia caseolaris+Kandelia candel community

     S. caseolaris has been planted at Dongzhaigang in the low tidal flat areas. After three years the trees are 8-10 meter high with a dbh of 8-20cm. It has dense breathing roots enabling the seeds of K. candel to establish naturally.
The mangrove-associated communities include:

    (1) Pandanus tectorius community

    This distinctive palm-like plant grows in relatively high areas reached only by the Spring tides. The plants are 3-6 meter high with a dbh of 10-15 cm.

    (2) Pogamia pinnata community

    P. pinnata forms a deciduous broadleaf forest and grows along the inside edge of the mangrove forest neighboring the mainland. The trees are 2-6 meter high with a base diameter of 10-25 cm.

    1.3.2 Fauna

    (1) Mammals (for a provisional list of mammals refer to appendix 7)
8 species of mammal have been recorded. Of these, the common otter Lutra lutra hainana is listed as a Grade 2 Nationally Protected Animal in China.

    (2) Birds (for a complete list of birds refer to appendix 3)

    A total of 194 bird species have been recorded at Dongzhaigang National Nature Reserve. These include the following Grade 2 Nationally Protected Animals for China, Chinese egret Egretta eulophotes, black-faced spoonbill Platalea minor, spoonbill Platalea leucorodia, Saunders' gull Larus saundersi and little bitten Ixobrychus minutus. It is possible that the white-eared night heron Gorsachius magnificus might occur.

   Of the 227 species listed in the China-Japan Migratory Bird Agreement (CJMBA), Dongzhaigang supports 75 species and of the 81 species in the China-Australia Migratory Bird Agreement (CAMBA), 35 species have been found in the Reserve. Many of these are wintering water birds which form large concentrations in Dongzhaigang Bay, especially around Wugoukou in the core area and Zhamen mudflats in the experimental zone.

   (3) Amphibians and Reptiles (for a provisional list of amphibians and reptiles refer to appendix 8)

   The major amphibians are frogs and major reptiles are snakes.

   (4) Insects (for a provisional list of insects refer to appendix 6)

    27 species of butterflies belonging to 6 families have been recorded throughout the Reserve.

   (5) Fish (for a provisional list of fish refer to appendix 4)

   A total of 103 fish species have been recorded in the Reserve. Most of these are estuarine species and some are of high economic value.

   (6) Benthic invertebrates (for a provisional list of fish refer to appendix 5)

    Dongzhaigang is rich in benthic invertebrates, with different species adapted to life in the inter-tidal sand- and mudflats, within the mangroves themselves and even in the freshwater influences parts of the estuary. Many benthos species have high economic value and fishing pressure for these species is intensively high throughout the Reserve. A total of 92 benthic invertebrates have been recorded at the Reserve.

   1.4 Conservation status

   1.4.1 Geographic location

    Dongzhaigang National Nature Reserve is situated in the northeastern part of Hainan Province, at coordinates of 110。32。-110。37。E and 19。51。-20。01。N. The estuary is adjacent to Luodou State Farm of Wenchang Municipality, Sanjiang State Farm of Qiongshan, Sanjiang Town, Yanfeng Town and Yanhai Town. The coastline of the reserve extends for 84 km and the estuary has a total area of 5,400 ha.

   The areas surrounding Dongzhaigang National Nature Reserve are mostly farmlands, salt pans, aquaculture ponds and forestry plantations. Dongzhaigang National Nature Reserve has good transportation infrastructure and communication facilities. The location of the reserve administration office is only 30 km from the provincial capital city of Haikou and 10 km from the Haikou Meilan International Airport currently under construction.

    1.4.2 Land tenure

    Official documents show that the Dongzhaigang Nature Reserve has a total area of 3337.6 ha under the administration of the Qiongshan County Government. The Reserve land is state owned and as such the Reserve administration (Hainan Forestry Bureau) has clear land tenure and rights to manage and utilize the land.

    1.4.3 Land use status

    Land use within the reserve area is very intensive. In most parts of the protected area the inter-tidal sand- and mudflats are intensively used by local communities for the collection of shellfish, fish and other marine and estuary resources. In many places the communities have demarcated large areas for oyster production (using wooden stakes driven into the sediment as settling substrates for the oyster spat) and these areas have clear community or family "ownership" or rights that exclude others. In other parts of the estuary, permanent fishing traps and nets are intensively laid out. Throughout areas which are not fished in this way or used for oyster culture, large numbers of local people gather on the falling tides to exploit the sand- and mudflats as they emerge above the receding waters.

   Exploitation of the mangroves trees themselves (i.e., wood cutting, fodder gathering) is strictly forbidden and is largely adhered to by the local communities. There is very little illegal cutting or gathering.
The mangrove channels are however fished and crabs and some shellfish widely collected throughout the mangrove forest.

   In peripheral areas there has been historical encroachment into mangrove areas to create salt pans (many of which have been recently converted to fish and shrimp ponds). Small-scale encroachment may still occur in some areas around the estuary.

    1.4.4 Conservation management

    Mangrove conservation throughout the area was significantly enhanced when the Dongzhaigang Nature Reserve was established in 1980. In subsequent years (1980, 1983, 1984 and 1996) the Qiongshan County Government issued notices underlining the need for conservation and sound management within the Dongzhaigang National Nature Reserve. This was followed by the enactment of the "Hainan Mangrove Conservation Regulation, 1998" by the Provincial People’s Council in September 1998. With subsequent support from government agencies of different levels, the Dongzhaigang National Nature Reserve conducted the following activities:-

   a) The municipal government established a Joint Conservation and Management Committee including representatives from relevant towns and villages to enhance the management of nature reserve.

   b) Two management stations-Sanjiang and Tashi, were established with full time wardens.

   c) A police station were established to investigate and deal with illegal activities.

   d) Permanent display boards have been erected to raise local public awareness.

    1.5 Institutional framework

    a) Jurisdiction and funding sources

    The Dongzhaigang National Nature Reserve is under the direct jurisdiction of Hainan Provincial Forestry Bureau. The Hainan Wildlife Conservation Station provides technical supervision to the reserve. The former Ministry of Forestry provided a lump-sum fund of RMB 750,000 at the beginning of the establishment of the nature reserve. The running costs and other investments are provided by Hainan Provincial Forestry Bureau and the Financial Bureau of Qiongshan City. A total of RMB 4.25 million has been invested to the reserve since its establishment.

   b) Institutional structure

   Several divisions have been set up within the Dongzhaigang Nature Reserve Administration, including a general office, scientific research group, tourism service, resource protection group, Tashi management station, Sanjiang management station and a police station. The reserve has a total of 32 staff.

   c) Infrastructure

   The reserve administration has one research and office building with a total area of 464 m2, one dining-room of 353 m2 and staff living apartments of 2010 m2. The reserve also own one tourism jetty, one patrol boat, one car and three motorcycles.

   1.6 Scientific research

   Under the previously formulated management guidelines of "Conservation, restoration and development", a number of scientific research projects have been implemented in Dongzhaigang National Nature Reserve. These include baseline biodiversity and resource surveys, determination of benthic biomass and inter-tidal productivity, mangrove fruiting and flowering phenology, mangrove afforestation trials, calculation of energy flows and pathways within mangrove ecosystems. The results of these studies have been published in several journals and internal documents. A summary outline of scientific research is given below:-

   a) mangrove resources survey

   Wide-scale surveys on mangrove resources at Dongzhaigang have been conducted on two occasions, in July-August 1980 and from July 1982 to June 1983. These surveys showed that the Reserve supported a total of 18 natural mangrove species belonging to 12 families and covered an area of 1773 ha. An island-wide mangrove survey for the whole of Hainan from July 1982 to June 1983 showed that Hainan supports a total of 27 mangrove species belonging to 16 families with a total area of 4836 ha. At that time the Dongzhaigang estuary supported nearly 40% of the mangroves in Hainan.

   b) Introduction of exotic species: Sonneratia caseolaris

    A four year research project entitled "The maintenance, reproduction and classification of Sonneratia caseolaris trees in China" was implemented in 1986 in cooperation with the South China Institute of Botany. As a part of this research, two recently described Sonneratia species from southern Hainan, S. hainanensis and S. paracaseolaris were also planted and bred at Dongzhaigang.

   c) Biomass and productivity of Bruquiera gymnorrhiza forest

   This project was carried out from January 1985 to 1990 in cooperation with the Department of Biology, Xiamen University.

   d) Afforestation trials for important mangrove species

   As part of the Eighth Five Year Plan a major research initiative entitled "Afforestation trials for important mangrove species" was conducted in cooperation with South China Institute of Botany between 1990-1995. A follow-up project entitled "Comparative trials of mangrove seed germination" was included in the Ninth Five Year Plan and was initiated in 1996.

   e) mangrove afforestation trials in different inter-tidal zones

   Afforestation trials have been carried out each year since 1981. During these trials a total of 285 ha of naturally-occurring mangrove species have been planted and 251 ha of them have been preserved. Appropriate techniques for mangrove afforestation have been developed and the most appropriate species for artificial plantation have been identified.

   f) Establishment of a mangrove tree arboretum

   A mangrove tree arboretum has been established within the Reserve. The arboretum contains mangrove species found locally, species that have been introduced from other parts of Hainan (from Wenchang, Lingshui and Sanya) and exotic species introduced from Bangladesh.

   1.7 Economic status of local communities

   The Nature Reserve is adjacent to 12 villages belonging to Yanfeng Township, Yanhai Township, Sanjiang Township and the Sanjiang State Farm. The total population size of these municipalities is 21,774 from 4,122 households. Local communities are supported both through agricultural and fisheries activities and the average annual income is about RMB 2,240 per capita. Each village has good transportation and electrical power supply.

   1.8 Public education and tourism

   Public education activities have focused on improving local awareness of conservation issues with a particular emphasis on mangroves and water bird conservation. In addition, limited activities to increase public awareness amongst tourists and local students have been undertaken.

   The mangroves at Dongzhaigang have become a popular tourist spot and the Reserve management authority and local entrepreneurs have established tourism facilities to cater for their needs. A small area of 136 ha near Changning Village was set aside for promotion of ecotourism as part of the Reserve management. Other facilities include a number of hotels and seafood restaurants, a boat tour service and a short mangrove trail with look out posts and picnic areas. As a result tourist numbers have increased dramatically and in 1997 there were 60,000 registered visitors.

    1.9 International cooperation and exchange

    The Dongzhaigang National Nature Reserve has drawn national and international attention since its establishment. Over 300 specialists and experts from Australia, Finland, Hong Kong, Japan, Malaysia, Thailand, The Netherlands, UK and USA, and have visited the Reserve since 1980.