Dynamic Of Landscape Pattern Of Wetlands In Min River Esturay, Fuzhou, Fujian, China

In this paper, the theories and methods of landscape ecology, along with remotesensing and GIS technology, were applied to research the ecosystem structure, landscapepattern, dynamic and driving force of Wetlands of Min River Estuary, located in Fuzhoucity, the capital city of Fujian province. The evolution of the Wetlands in Min River Estuaryhas been discussed since 1986s. The sustainable control strategies of wetlands landscapeof Min River Estuary were put forward based on landscape ecological planning andrestoration. The results help reveal mechanism of the natural processes and humanactivities on the evolution of wetlands landscape, and provide new perspectives andtheoretical basis for protecting the wetland landscape, restoration of damaged wetlandecosystem and landscape ecological planning.The main findings are listed as follows:1. Systematical analysis of the wetlands ecosystem structure in Min River EstuaryThrough surveys and data analysis, the study of the structural composition of wetlandecosystem ranges from the communities, zoo benthos, to fish and birds. Min River Estuarywetland vegetation was mainly composed of Phragmites australis and Cyperus malaccensis,the important primary producers of Min River Estuary biomes, which were also most widelydistributed with the most types and biomasses. Birds of Palaearctic region in Min RiverEstuary can represent characteristics of birds there. While Shanyu Beach, Puxia Chau,Sixty Chau presented higher bio-diversity index in birds, Chang'an Chau, Bianfu Chau'sindex were lower. The inshore low-salt water, estuarial half-salt freshwater, freshwaterwere three main ecological types of invertebrates. Shanyu Beach covers the largest areaof wetlands of Min River Estuary, with the largest species of vascular plant and largestnumber of birds.2. Establishment of landscapes classification system of Min River EstuaryTaking wetland topography, hydrology, matrix and surface vegetation cover types etc.into consideration, wetland landscape was divided into 12 kinds of landscape typesaccording to the three-tier classification system, of which the third tier included eight kindsof wetlands, namely, sandy wetlands, mud swamp wetland, shrub wetlands, freshwaterwaters, tidal fiat reed wetlands, high salinity tidal fiat wetlands, salt waters, and estuariessandbank wetlands. GIS was utilized to set up spatial database and map landscape typefigures during three different periods.3. The landscape pattern, dynamic and driving force of Min River EstuaryNatural wetlands had the largest number and area patch, while water area had theleast number, but the greatest average patch area. The study of water area in wetlandsmainly concentrated on the matrix and corridor of the landscape. The patch fractaldimension of natural wetlands were relatively larger, with more complex shapes, and that of paddy fields, aquaculture ponds and other wetland were relectively smaller, with formalborder and better self-similarity. Shape Index of river wetlands was bigger than that ofcoastal wetlands, for wetlands in the river by a greater impact on human disturbance, ahigh degree of fragmentation pacth. The natural wetland landscape diversity index,evenness index was more than those of the artificial wetlands and non-artificial wetlands.The fragmentation of patch was serious in urban area than in coastal area, whereas thenumber, size and the average patch area of urban area was larger than those of coastalarea. The fragmentation of urban landscape was much more serious than that of coastalarea, with lower diversity index, and evenness, but higher advantage degree.The number of pacthes increased and average size of pacthes decreased in the study,and the trend of those changes are more obvious. The number of patches has beenincreased by 40.70% and average size of patches has been decreased by 9.29%, anddensity of patches has been increased 40.8% in the study area from 1986 to 2003. Thenumber of patches in natural wetlands has been increased by 20.57% and the area ofpatches has been decreased by 9.29% in the past nearly 20 years, which demonstratesthe fragmentation and shrinking of natural wetlands. The area of non-wetland hasincreased by 89.09% while the patches of non-wetland have increased by 71.67%. Therewas a slight increase in diversity index of the entire studied area. The diversity index ofwetland landscape has increased, reflecting differences in the proportion of area coveredby different kinds of landscapes were diminishing. Moreover, landscape structure tends tobecome more complex. Non-wetland landscape diversity declined because land use ofmain towns gradually expanded. The difference between area covered by town and byother non-wetland landscape was increasing year by year. The transition among differenttypes of landscapes was also studied in the area. Since 1996, the transition from riverwetland to artificial and non-artificial wetland has accelerated. In non-wetland landscape,the urban construction sites were mainly used to be shrub wetland, muddy wetlands, ricepaddies, sandy wetlands, etc., which accounted for about 46%, larger than the proportionbetween 1986 to 1996.The driving force analysis of wetland landscape pattern showed that the increase inpopulation and rapid urbanization were the root causes of landscape fragmentation, poorstability of the Min River Estuary wetland. Disorder of massive sand mining resulted in aserious deformation of the river bed, affecting the stability of river morphology. Theactivities of sand mining and blowing had direct impact on the Min River Estuary, changingthe shape and size of wetland. The engineering projects such as flood control banks andreclamation from sea directly reduced the area of wetlands, changed the sediment,hydrodynamic and main factors related to the size of wetlands, vegetation, bird habitats,proliferation and biodiversity.4. Sustainable ecological control strategies based on landscape ecological planningand restoration of wetland landscape of Min River EstuaryA set of ecological comprehensive evaluation system was established of Min RiverEstuary wetlands. A comprehensive analysis in light of ecological vulnerability wasconducted through three aspects, namely, the affecting factor, the performance factor and restrain factors, providing basis for ecological landscape planning in Min River Estuary.A comprehensive scheme of ecological landscape planning of Min River Estuary hasbeen constructed, with three wetland spatial districts, including nature reserves, ecologicalfunctional areas, ecological wetlands park. The corresponded control and conductmeasures were proposed in terms of protection of wetland and ecological construction.To solve the degradation of ecological functions of wetlands in some importantwetland, a series of ecological restoration programs were proposed, including therestoration of vegetation, waterfowl habitat protection and the restoration from river topaddy fields.