Study On Land-use Change And Its Driving Forces In Urban-rural Fringe

The urban-rural fringe is the most prominent area in the process of urbanization, which embodies not only the transformation of landscape, but also the transition of ecological function in the study area. The transformation of landscape always refers to the transformation of rural landscape into urban landscape, exploitation of land with low density to highly intensified one and expansion of urban space, meanwhile the transition of ecological function means the occurrence of obvious difference in the process of substance circulation and energy flowing. The urbanization of urban-rural fringe could be depicted by landscape structure and its change which refers to spatial and temporal difference of different landscape factors configuration in the study area. The understanding of the characteristics of landscape structure, landscape change and its driving force is significantly meaningful to the research next step for ecological process in the study area.The author regionalized the urban-rural fringe into sub-regions which are interior fringe area, central fringe area and exterior fringe area respectively; selected the three typical regions of Chaoyang District (interior fringe area), Shunyi District (central fringe area) and Miyun County (exterior fringe area) in Beijing metropolis as the study area; applied the three TM imageries with the same temporal phase of 1996, 2000 and 2005 and used 3S technologies, landscape ecological methodologies and statistical models to analyze land use in the study area from land use dynamic change and landscape structure change point of view; studied land use change driving force with the combination of qualitative and quantitative methods.The study result was as follows: construction land dominates land use types followed by arable land in the Chaoyang District, meanwhile arable land and construction land takes predominant and secondary positions respectively in the Shunyi District and forestland, grassland and construction land prioritize the land use of Miyun County in a descending order. During the time period of 1996-2005, the acreage of construction land of the study area has been increasing, while the acreage of forestland, arable land, grassland and water body have gradually been declining. And the change of arable land and construction land is very obvious. The fact that construction land was mainly transformed from arable land was acquirable, which tends to be same during the two time intervals of 1996-2000 and 2000-2005. By using the index of comprehensive land use dynamic degree, huge difference existed in the land use change among Chaoyang District, Shunyi District and Miyun County, which means that the change of land use in the Chaoyang District is very fast, but it is very slow in the Miyun County.From landscape ecological point of view, forestland, arable land and construction land predominates landscape types in a descending order with the embedment of grassland and water body. The regularity that diversity index is maximum in the Shunyi District and it is minimum in the Chaoyang District could be found by using different landscape heterogeneity index of three years 1996, 2000 and 2005 in the whole study area and sub-regions to comparatively analyze. Analysis from the change of landscape heterogeneity index for the two time period of 1996-2000 and 2000-2005 point of view indicated that the diversity index decreased and dominance increased in the Chaoyang District; that diversity declined and dominance, fragmentation degree and fractional dimension all went up in the Shunyi District; that diversity index went down, and dominance, fragmentation degree and fractional dimension increased in the Miyun County. By analyzing land use change driving force in the qualitative and quantitative ways, economic development, population growth, industrialization, urbanization and policy were identified to be the affecting factors for land use change.Targeting at the existing problems of urban-rural fringe in the Beijing metropolis, the author put forward several reasonable suggestions for land use with the integration of the affecting policies and statues of urban-rural fringe from establishment of the People's Republic of China to present: emphasizing ecology and reasonable layout; perfection of the general land use planning; strict controlling of land market and perfection of land transaction system; improvement of intensive management level of agricultural land; restructuring land use and optimizing land use circle layout model; improvement of awareness of land protection and consolidation; automating land use administration. These suggestions could provide the theoretical basis for sustainable development of land use in the urban-rural fringe of Beijing metropolis.