Research On Land Use/Land Cover Change And Driving Forces Mechanism In Coastal Zone Of Shanghai

Coastal land use/cover change (LUCC) is the focus of global change and land science in research area. The coastal zone of Shanghai is located in the eastern part of the Yangtze River Delta. Since1990s Shanghai has entered into the critical period of transition and thus the coastal land-use coverage has also been changed dramatically, which occurs concomitant with the rapid and sustained economy development, industrial restructuring, urbanization and the implementation of major national strategies and projects including the open-up of the Pudong new District, the construction of the Pudong International Airport, the development of new coastal towns as well as the establishment of industrial zones of Jinshan and Fengxian. Using the coastal Shanghai as research area, this paper builds up a theoretical and methodological system for coastal LUCC and explores the process and the driving mechanism of LUCC for coastal Shanghai in1990-2009by applying theories and methods of land science, landscape ecology and GIS&RS. Based on land-use classification and wetland classification, the paper makes a study on the LUCC pattern, process and changing mechanism inside and outside of the levee. Furthermore, this paper makes estimation on coastal wetland salt marsh vegetation aboveground biomass, which later provides a basis for the assessment of wetland ecosystem carbon storage. Therefore, this study is necessary both theoretically and methodologically. On the one hand, this study provides a new angle of view for LUCC research and enriches the theories and methods of land science. On the other hand, the findings reveal land use/cover characteristics and rules of the pattern change in the economic transformation of Shanghai coastal area and provide data to support the comprehensive utilization and management which is significant to promote the economic development of Shanghai or even the Yangtze River Delta region. In this study, the following conclusions have been drawn:(1) Shanghai coastal zone land use has changed significantly in1990-2009, wich can be mainly reflected in the phenomenon of'one addition and one reduction'.'One addition'refers to the soaring construction land, while'one reduction'means the sharp loss of arable land. The reclaimed land reached511.71km2within the19years marking the peak value since1950.(2) The LUCC of Shanghai coastal area in1990-2009can be divided into5type: the new enclosure land changed into other land-use, other land use changed into construction land, the new enclosure land changed into arable land, aquaculture land changed into other land use, arable land changed into construction land. Among them, the other land-use is the main source of construction land increase, accounting for29.8%. This is followed by arable land, accounting for22.37%of the transferred area. Land for construction is the biggest beneficiary for the arable land coverage change, accounting for25.6%of total arable area. The next is other land uses, accounting for11%. The new enclosure land has mostly been transferred into other land use, accounting half of the new enclosure land, followed by arable land, accounting21%for the new enclosure of land.(3) Landscape pattern changes during1990-2009can mainly expressed as the gradual decrease of landscape heterogeneity and fragmentation in coastal center and northern areas of gradually decreased. In the southwestern part of the studies area, however, the heterogeneity of coastal zone is increased, and fragmentation is also gradually increased. In the view of types and levels of spots, Shanghai coastal landscape has been gradually shifted from the landscape pattern of arable land and other land being the matrix and the water&aquaculture being the mosaic into a new pattern of multi-spot balance composed of cultivation land, construction land, other land, forest and grassland.(4) Shanghai coastal wetland area has been reduced gradually by483.8km2in1990-2009. In such a decrease, the offshore and coastal wetland area was reduced from2938.74km2in1990to2368.51km2in2005. The inland wetland is increased slightly.(5) Using high resolution RS data of SPOT5satellite and data obtained from field observation and laboratory measure, this paper makes a calculation on the net primary productivity on the typical vegetation of eastern coast of Chongming, i.e. Phragmites australis, Spartina Alterniflora, Scirpus mariqueter. The result showed that the wetland salt marsh vegetation aboveground biomass of Chongming Dongtan: Spartina Alterniflora>Phragmites australis>Scirpus mariqueter.(6) Using qualitative and quantitative methods, this paper makes an analysis on the driving mechanism of coastal zone LUCC during1990-2009. The enclosure of land and large projects of construction are the main human factors for offshore and coastal wetlands reduction. Principal component analysis and gray relational method are applied to analyze driving factors of coastal land use types. The result shows that the important driving factors affecting various land use type distribution are agriculture, economy and enclosure land. Using typical correlation analysis model quantitatively this paper analyzes the relationship between driving factors and land use change. The result shows that demography and economy are the main factors that have effects on coastal LUCC.(7) Using GM (1,1) model and the linear interpolation method, this study makes a prediction on the changing trends of coastal land use types. The prediction shows that construction land will still maintain a high growth while arable land might decrease gradually during1990-2009. Finally, combined with the research results of this study, the paper puts forward8pieces of suggestions and countermeasures for the sustainable development of land use.