基于MCR模型的城镇生态安全格局构建和建设用地开发模式

Construction of urban ecological security pattern and construction land development based on MCR Model

近年来,在中国城市土地开发的顶层设计中越发强调生态空间的重要性,充分识别城市生态安全格局并探讨建设用地空间扩展格局成为划定生态保护红线、确定城市开发边界和"三规合一"空间管制等政策实施的迫切需求。该文以唐山市为例,基于"生态过程—格局"理论和GIS的空间相关性分析、距离分析和叠加分析等方法,从综合水安全、地质灾害预警、生物生境保护、水土保持、游憩安全5个方面,整合构建了底线安全格局、缓冲安全格局和最优安全格局3种不同等级的综合生态安全格局。该文在MCR模型算法引入不同等级"源"的权重系数,以综合生态安全格局为阻力因子,并结合城镇中心的吸引力、主要道路的吸引力和政策调控(区域开发重点)等城镇用地扩展影响因素,得到在不同约束条件下的区域空间扩展阻力面,分别确定了唐山市在"生态安全约束型""经济增长主导型"和"生态与经济并重"3种模式下城镇空间可能的发展范围,经过多方案比较,"生态与经济并重"城镇建设用地空间发展模式是未来城镇健康有序发展的最优模式,这种发展模式既有利于减少大规模、高强度的城镇化和工业化过程所造成的城市发展和环境保护之间的用地冲突,也可为城市用地布局规划和生态红线划定提供科学依据。

In recent years, the importance of ecological space has been emphasized in the top-level design of urban land development in China. China is now in the stage of fast urbanization and the pace of industrial structure adjustment, the expansion of the construction land space is the most obvious sign of the transformation of the urban land landscape, and contradiction between cities and towns＇ competition and control of regional space is becoming more and more prominent. Identifying the urban ecological security pattern and discussing the spatial expansion pattern of construction land have become an urgent need for the implementation of the policy for delineating the red line of ecological protection, determining the boundaries of urban development and the ＂Three-planning united＂ spatial control. Using Tangshan City as a case, this paper was based on the theory of ＂Ecological process—Pattern＂ and the functions of spatial correlation, distance and superposition analysis of GIS. In this study, we integrated geostatistics analysis, spatial correlation analysis, distance analysis and overlay analysis. It obtained comprehensive ecological security pattern of Tangshan City by 5 single ecological security patterns： comprehensive hydrology security pattern, geological disaster pre-warning security pattern, biological habitat protection security pattern, soil and water conservation security pattern, and recreational security pattern. The integrated ecological security pattern under 3 different levels accounted for 15.31%, 50.08% and 12.70% of the total area respectively. In this paper, we built and improved MCR（minimal cumulative resistance） model, from which the weight coefficient of different levels of ＂source＂ was introduced. This paper took full account of the expansion capability of different extended sources. By using comprehensive ecological security pattern, attractiveness of the center of town and the main road and policy adjustment factor as resistance, and then the resistance surface of the regional space under different constraint conditions was obtained to determine the urban development scope under the condition of ＂Ecological security constraint pattern＂, ＂Economic dominance pattern＂ and ＂Ecology Economy win-win pattern of urban spatial expansion＂, respectively. The spatial expansion of urban land was restricted by many factors, not only to consider the regional ecological and environmental factors, but also to pay special attention to the regional social and economic conditions and policy oriented factors. Through multi-scheme comparison, we found that the spatial expansion pattern driven by the conditions of ＂Ecology Economy win-win pattern of urban spatial expansion＂ development model was the best model for the healthy and orderly development of cities and towns in the future, and was of great significance for optimizing the layout of land use and the protection of the ecological environment, moreover, which can effectively predict the scope of urban space development.On the basis of all above, considering the influence factors of urban development, the improved MCR was used to analyze the spatial expansion pattern of urban construction land use under different patterns, and to explore the appropriate ecological security pattern of urban development, which reduced the land conflict between urban development and environmental protection caused by large-scale and high-intensity urbanization and industrialization process, and put forward a scientific basis and reference for urban land layout planning and ecological red line delineation.