基于自然生态单元的中国城乡建设用地空间格局特征分析

基于经济和社会视角的国家尺度城市空间格局研究取得重要进展,而全国城市空间格局的自然生态关联性呈现新的研究需求。由此通过自然生态单元等级划分并与城乡建设用地叠加,揭示了全国城乡建设用地在自然生态单元的空间格局特征及其主要问题:在一级生态功能区中,生态调节区面积最广,主要分布在我国西北、西南和东北等生态脆弱地区,但其内部城乡建设用地占比最小仅为0.69%,产品提供区城乡建设用地的占比为2.74%,人居保障区面积最小且集中分布在我国东部沿海地区,但其城乡建设用地占比最大,高达11.20%;城乡建设用地在自然生态单元的分布差异总体由自然地貌与大河流域特征决定,城镇群区、农产品提供区和土壤保持区占据79.54%的城乡建设用地,位于平原水网、丘陵、喀斯特和丹霞等地貌特征为主的胡焕庸线东南部;城乡建设用地分布格局也表现为东多西少,与我国三大阶梯的地势格局分布较为一致;上述格局关联性体现了人和环境之间的相互依存关系,但近些年来在开发需求膨胀和工程技术进步等人为因素驱动下,城乡建设用地呈现向较高海拔地区的扩张趋势。这为新型城镇化背景下城乡可持续发展和生态安全格局构建提供基础信息,也为辨识中国城市空间组织和演化机理提供技术支撑。

ANALYSIS ON SPATIAL PATTERN OF URBAN-RURAL CONSTRUCTION LAND IN NATURAL ECOLOGICAL REGIONALIZATION IN CHINA

Researches on urban spatial pattern at national scale from the viewpoint of social-economic development have made very valuable progresses,but the spatial relationship between urban spatial pattern and natural ecological pattern at national scale has not been greatly paid attention.Natural ecological safety is constitutive of the current era of urbanization and must be linked to urban spatial development.A better understanding of the sustainability of urban development must rely strongly upon available information about the causes,chronology,and effects of urbanization.Therefore,this paper analyzed the spatial pattern of urban-rural construction land in natural ecological regionalization.By the overlay analysis of natural ecological units and urban-rural construction land,the paper revealed that,in the ecological function areas (The First Level),the areas of ecological regulation function are distributed most widely in China's northwest,southwest,and northeast ecological fragile areas,with a minimum ratio of only 0.69％ in total area of urban-rural construction land.The urban-rural construction land area with ecological supply function accounted for 2.74％ in total area of urbanrural construction land.The urban-rural construction land with habitat security function smallest area is concentrated in the eastern coastal areas of China,but accounted for the largest,up to 11.20％ in total area of urban-rural construction land.The spatial differences of urban-rural construction land in the natural ecological units are linked to the natural characteristics of natural geometry and river basins.The function areas including cities groups habitat,agricultural products supply and soil conservation regulation occupy 79.54％ of the total urban-rural land which is located in the plain,river networks,Karst hills,and Danxia geomorphology area mainly in southeastern Hu line.The areas of habitat security function are mostly distributed in the Circum-Bohai Sea Economic Zone,Yangtze River Delta and Pearl River Delta.There are several city groups and many developed towns in the surrounding area.The three areas with the function of habitat security have the greatest area of urbanrural construction land which has been very rapidly expanded around the large cities and taken up a large number of cultivated land and natural landscape.The urban-rural construction land distribution pattern is also consistent with the distribution pattern of China's three major geomorphologic regions.The above results are expected to reflect the spatial interdependent relationship between human and environment systems,but in recent years,the expansion of urban-rural construction has been driven by the development demand expansion and the progress of engineering technology.The paper provides the basic information for the sustainable development of urban-rural areas and the construction of ecological security pattern in the context of the new urbanization,and also provides technical support for the identification of urban spatial organization and evolution mechanism in china.