Small And Medium-sized Urban Land Expansion Of Urban Ecological Security

The urbanization process of China is steadily accelerating. With the rapid development of economy, some big cities in China are bearing the enormous pressure of environment deterioration. Some of them have been perplexed by serious urban problems such as crowded space, environmental pollution and low percentage of vegetation, etc. Since small and medium-sized cities are in the rapid expansion of process, it is important to avoid the foreseeable consequences that have already been observed in big cities, not mentioned the goal of promoting these cities'sustainable development. As one of many prospering small and medium-sized cities in China enjoying rapid economic development, Zhangqiu's dilemma of urbanization and ecological security requires serious attention. By summarizing relevant domestic and international research on eco-security, the thesis analyzes effects of urban land-use growth on ecological security. In the thesis study, Zhangqiu is taken as the typical instance of small and medium-sized cities, and according to the current framework of eco-security assessment, it studies the level of ecological security in the process of land-use growth in Zhangqiu. This work is important to harmonize the relationship among economy, society and ecology, to optimize the urban function region, and to improve the urban competitiveness.(1) The thesis summarizes relevant theories of eco-security and eco-security assessment. It uses the conceptual model of PSR, in combination with the consideration of Zhangqiu's real conditions, to construct the indices system of corresponding urban eco-security assessment. The evaluating indices are divided into four levels, including target, norm, factor and index, and then twenty-six indexes were chosen to reflect the essence of urban eco-security in small and medium-sized cities. Through the approach, the study shapes a method for complete assessment of urban eco-security.(2) This research analyzes the main characteristics of urban land-use mode in small and medium-sized cities. Zhangqiu's urban land-use growth experienced four stages successively:spontaneous stage (before 1979), stable initial stage (from 1979 to 1995), stable growth stage (from 1995 to 2003), and rapid expansion stage (from 2003 to present). As a result, the urban construction area in Zhangqiu has expanded to 46.2 km2, which is nearly 7 times compared with 1980. Characteristics of such space structure development were also analyzed in this research.(3) Through analyzing current situation of Zhangqiu's environment, the study reveals the ecological and environmental conditions in the process of land-use growth. It points out that in the process of hasty industrialization and urbanization, the economy's rapid growth could threaten the urban eco-security. The problems of current urban land-use and ecological protection are actually issues about the relationship between economic development and ecological environment. Ecological problems caused by urban land-use growth bring a series of environment, resources and social effect.(4) According to the proposed small and medium-sized cities'evaluating indices system of urban eco-security, with the help of analytic hierarchy approach, it evaluates the levels of eco-security from 2002 to 2008. The results indicate an upgrade in the spell of seven years. However, there is a mismatch within every single index, moreover, a great difference in comparing the speed of increase among all indexes of subsystems. By analyzing all the indexes, it can be seen that Zhangqiu' urban eco-system is gradually better, but the capability of protecting resources and environment is enduring an overwhelming pressure in Zhangqiu. Factors leading to this pressure include fast-growing of the modern city, such as high population density, high urban unemployment rate, large radix of agro-population and the weak eco-consciousness etc. All these directly affect urban eco-system. On the other hand, those evaluated facts such as the state of social structure is well-established, the current investing environment is prosperous, the economic development is stable as well as the effects of environmental management is outstanding, are beneficial to Zhangqiu's eco-security.(5) The research provide a scientific background for planning the urban development of Zhangqiu by analyzing its urban eco-security level, and some measures for improving Zhangqiu's urban eco-security condition are also proposed in the thesis study.