The Character Of Ecological Environment And Biodiversity Protection Of North Branch Of Changjiang Estuary Wetland

This paper have mainly studied three aspects of content of north branch of Changjiang estuary wetland including the character of ecological environment,biodi- versity and nature reserve construction.The results are showed as follow:1.North branch of Changjiang estuary wetland is a complex system consisting of coastal tidal flat wetland ecosystem, estuary wetland ecosystem and artificial wetland ecosystem. It has rich ecosystem types, high heterogeneity and higher primary productivity. And it's the good habitat and foraging site of migrating birds. But its quality of ecosystem is common and easy to be interfered by humans.So it's desiderated to take scientific and effective and protective messures.2. The sandbank and tidal flat wetland vegetation of north branch of Changjiang estuary naturally have obvious zoned distributing character. From outer to inner turns is: bare flat- saline alga zone- Scripus mariqueler community zone-Scirpus triquerter community zone - Phragmites australis community zone -mesozoic vegetation zone,The basic mode of nature evolution is: bare flat→saline alga zone→Scripusmariqueler community→Scirpus triquerter community→Phrag- mitesaustralis community→mesozoic vegetation.This mode goes from low to high with the heighten of filling up and enlargement of sandbank (or tidal flat).3. North branch of Changjiang estuary has 57 species,157 genera and 212 famil -ies of seed plants.The floristic components have character as following: geographic -al elements of species is relatively simple;there are more species of world distributi -on and tropical genera,and there have world blazon predestined relationship and tropical predestined relationship.Composite,standing grain,legumina have absolutely predominance make of the backbone of floristic.Seed plants are mainly made up of herbage plants.Scripus mariqueler community, Scirpus triquerter community and Phragmites australis community are three main wetland flora types.Flora is at the stage of primary evolution and the structure is simple,biodiversity is lower,vegetation has the character of original nature disposition,species components is monotony,for instances it is made up of single specy flora community.4. North branch of Changjiang estuary has 216 species,41 families and 16 orders of birds. Most of species are migrating birds,passenger birds followed and resident birds only accounts for small proportion.Among the migrating birds,winter migrants give priority to summer migrants.Waders,geese and ducks,umbrette and gull are the main bird community types and there are more types of rare and endangered birds.Inter-families and inter-species diversities of birds are high, the distribution is uniform and have more non-single species. Bare flat and saline alga zone, inner-bank breed aquatics pond, Scripus mariqueler and Scirpus triquerter community zone, reed community zone are four typical habitat which are waterfowl- l's main habitat.Composition of birds community between Phragmites australis community zone and other three habitats has large difference.The diversity of bird community is the highest in inner-bank breed aquatics pond and the lowest in Phragmites australis community zone.5.Based on theory of island biogeography advanced by MacArthur and Wilson, and the major principles of designing nature reserve advanced by Diamond, combin- ed heterogeneity population theory ,ecology evolution theory and sustainable develo -pment theory with the situation of soil utilizing and social economy of Qidong city, the paper has made a planning of north branch of Changjiang estuary wetland nature reserve of Qidong and its zoning of function areas and presented a sustainable devel -opment mode of the nature reserve including ecological measures, industry devolop -ment measures and policy measures.