城乡交错带的三维动态识别及空间演变机制——以厦门市为例

城乡交错带是人地系统矛盾最集中的区域之一,对其进行科学识别与动态监测对中国新时期城乡统筹和空间治理有重大意义。提出了一种综合城乡交错带三维特征指数、动态线性加权与空间自相关分析的空间识别方法,基于LULC数据提取了厦门市1990—2018年城乡交错带的空间范围,进一步通过GIS揭示其格局规模、土地利用、空间功能的演变特征和机制。结果表明：① 城乡交错带三维动态识别方法在长时序空间识别中效果良好。② 近30 a厦门城乡交错带规模持续扩大并向陆域腹地推移,包括“组团生成-连片外延-跳跃扩张-内部分异”四种模式,存在外圈扩张与内圈消减的双重过程。③ 土地利用动态和面积变化速率分别在2010年达到顶峰26.85%和22.70 km²/a后降低并趋稳,研究期内建设用地对耕地和其他生态空间不断侵蚀。④ 空间功能混合度持续增强,复合功能空间占比由63.80%提升至75.72%,其中生产、生态功能在城市化前期和中期存在较强权衡关系,生活功能最薄弱。⑤ 城乡交错带空间演进包括三个阶段,受经济、社会、政策、环境四方面因素共同驱动。研究对补充城市地域结构理论体系有一定价值,为城乡交错地区国土空间规划实践提供支撑。

Three-dimensional dynamic identification and spatial evolution mechanism of urban-rural fringe:A case study of Xiamen

Urban-rural fringe (URF) is a region with intense conflicts in the human-environment system. Scientific spatial identification and dynamic monitoring of URF are of great importance to China’s urban-rural integration and spatial governance in the new era. The previous methods show limitations in the URF identification of multi-center cities. Moreover, the evolution mechanism of URF is not clear at present due to inadequacy of long-term monitoring. In this research, a URF spatial identification approach integrating the three-dimensional characteristic index of URF, dynamic linear weights and spatial autocorrelation analysis (Getis-Ord Gi*) was put forward. Through this approach, the URF of Xiamen in 1990, 2000, 2010 and 2018 was identified based on LULC data. Furthermore, the characteristics and driving mechanism of URF evolution was analyzed with application of GIS platform from aspects of spatial pattern, land use and function. The results were as follows: (1) The approach of three-dimensional dynamic spatial identification of URF proved to be effective in long-time identification circumstances. (2) In the past 30 years, the URF of Xiamen kept expanding from 240.50 km² to 723.20 km² towards inland region. This process contains four stages, i.e., group forming, integrated expansion, leaping expansion, and internal differentiation. Additionally, it showed characteristic of simultaneous outward loop expansion and inward shrinking. (3) Dynamic degree and changing rate of land use in URF decreased and stabilized after peaking at 26.85% and 22.70 km²/a, respectively, in 2010. Besides, construction land continued occupying cultivated land and other ecological spaces, and the balance of land use structure relied on supplement of external ecological resources. (4) The proportion of spatial units with multifunction continued to increase from 63.80% to 75.72%. In addition, the trade-offs between functions of production and ecology were intense in the early and middle stages of urbanization. In the three spatial functions of URF, living function accounted for the smallest proportion. (5) There is a three-stage evolution path of URF, which is driven by factors of economy, society, policy and environment. This research can enrich theories related with urban spatial structure. In practice, it can also provide quantitative support for the decision-making of spatial planning in urban-rural areas.