Study On The Ecological System In Yancheng Coastal Wetlands

The thesis made an research into marsh types, the distribution principles of marsh and vegetations,the succession of marsh and vegetations, the composition of main marsh waterfowl system, raw marsh, inning marsh soil physical and chemical properties and marsh protection etc in Yancheng. The conclusion can be drawn as follows.1.Yancheng marsh can be divided into systems of crude marsh, half-artificial marsh and artificial marsh, offing, types of coastal marsh, fluvial marsh, lake marsh and river marsh, basic types of shallow sea water area, tide silt beach, bayou water area, permanent rivers, seasonal or intermittent rivers, permanent fresh water rivers, seasonal fresh water rivers, wetland of the reservoir and pool etc. The total area amounts to 79,000 hectares.2.Yancheng marsh is distributed by 190 kinds of phytoplankton, 5 phylum,57categories,84 kinds of fixity alga, 480 kinds of seed plants. Among the plants, sedge family and grass family are superior in number. Vegetations types were divided into salty growth,swampy growth,meadow and aquatic vegetation, and so on .3.The succession of marsh displays the process of foliage community succession, i.e., the growth of marsh, especially the change of soil moisture and nutrition, results in the change of foliage categories and communities. Marsh foliage communities'succession is caused by the natural factors such as climate, hydrology, physiognomy and soil, objectively reflecting the process of the formation, growth and succession of marsh.4.Yancheng marsh is mainly distributed by 241 kinds of birds with the subjection of 17 items and 42 sections. Among the 17 items, the birds from ciconiformes and anseriformes dominates. Besides, there lie 11 kinds of anseriformes, 11 kinds of linnaeus, 13 kinds of galliformes. Of the 241 categories, 60 belong to treasure birds under national protection. Resident birds and summer migratory bird runs up to 166 categories. The rest remains winter migratory birds.5. Marsh soil physical and chemical properties differ prominently. The properties of swamp coast, sea band shelter belt, phagmites communis trin pond, spartina angelica swamp etc. are superior to those of tide beach of the contrast. Moreover, the amount of all-nitrogen, all-phosphor, efficient phosphor, organic substance content of soil decreases with the depth of soil while the bulk density, pH and salt increase. There is a close and complicated relation between different soil physical and chemical properties.