环京津城市群生态系统服务的时空演变与驱动因素

城市群已成为全球经济竞争的新空间单元，在促进城镇化建设，实现资源优质配置和发挥辐射带动作用等方面发挥着重要的功能。但剧烈的社会经济活动必然会对城市群生态系统服务造成破坏，因此开展城市群生态系统服务的时空演变研究，进而探索不同驱动因子对其的作用机制具有重要意义。目前，在已有的研究中缺少对城市群尺度和长时间跨度下的生态系统服务水平演变与驱动因素探究。为此，选取京津及环京津地区为研究区域，通过总结区域生态问题，构建起研究区域生态系统服务评价体系，并对2000-2018年生态系统服务进行计算，分析时空演变特征。然后，通过最小二乘法模型（Ordinary Least Squares，OLS）筛选出潜在的驱动因子，并导入地理加权回归模型（Geographically Weighted Regression，GWR）进行地理加权回归计算。最后，通过对结果分析，探讨自然和社会因子对生态系统服务的作用机制。研究结果表明：1）2000-2018年，研究区域生态系统服务呈现出先上升后下降，在2015年达到最高值的发展特征。2）在空间上，研究区域生态系统服务内总体上呈现燕山山脉及太行山山脉北部区域为生态系统服务的高值区域，坝上区域为低值区的空间分异特征。同时，生态系统服务演变在空间上呈现以燕山和太行山为界，燕山和太行山区域呈现先减弱后提升的趋势，西北区域整体呈现减弱趋势，东南区域从2015年起逐渐降低的空间演化特征。3）在驱动因素方面，自然环境和社会经济因素对生态系统服务的驱动作用从强到弱排列依次是：降雨量 > 土壤含沙 > 人口密度 > 温度 > 基础设施密度。4）其中，人口密度、土壤含沙量、基础设施呈较为明显的负相关驱动特征，降雨量呈较为明显的正相关驱动特征，温度则呈南部负相关，北部正相关，由东南向西北影响增强的趋势。本研究通过评估环京津城市群生态系统服务，分析区域生态系统服务的分析演变特征，并探索区域自然、社会因子对生态系统服务的驱动作用，为环京津城市群未来的生态环境保护和规划策略制定提供了科学指导和决策依据。

Spatial and temporal evolution and drivers of ecosystem services in Beijing, Tianjin and the Beijing-Tianjin Ring urban agglomeration

Urban agglomerations have become a new spatial unit for global economic competition and had important functions in promoting urbanization, achieving high-quality allocation of resources and driving economic development. Intense socio-economic activities, however, are bound to cause damage to the ecosystem services of urban agglomerations. It is important to conduct studies on the spatio-temporal evolution of the ecosystem services of urban agglomerations and explore its driving factors. In this study, Beijing, Tianjin and the Beijing-Tianjin Ring were selected as the study area. The experiments constructed an ecosystem service evaluation system for the study area by summarizing regional issues, calculated ecosystem services from 2000-2018, and also analyzed their spatial and temporal evolution characteristics. Then, the potential drivers were screened out by the ordinary least squares model of the experimental data and imported into the geographically weighted regression model for regression. Finally, the driving role of natural and social factors on ecosystem services is explored, through an analysis of geographically weighted regression results. Firstly, the ecosystem services of the Beijing-Tianjin-Hebei urban agglomeration showed an upward and then downward trend from 2000 to 2018, reaching the highest value in 2015. Secondly, Spatially, the ecosystem services in the study area generally show the spatial differentiation characteristics of high value areas in the northern regions of Yanshan Mountains and Taihang Mountains, and low value areas in the dam area. At the same time, the evolution of ecosystem services spatially shows the boundary between Yanshan and Taihang Mountains, with the Yanshan and Taihang Mountains regions showing a trend of first weakening and then improving, while the northwest region shows an overall weakening trend and the southeast region gradually decreases from 2015 onward. Thirdly, Natural environment and socio-economic factors drive ecosystem services in descending order of strength:rainfall > soil sand content > population density > temperature > infrastructure density. Fourth, the population density, soil sediment concentration and infrastructure showed significantly negative correlation driving characteristics, while the rainfall showed significantly positive correlation driving characteristics, while the temperature showed negative correlation in the south and positive correlation in the north, with an increasing trend from southeast to northwest. Overall, by assessing the ecosystem services of the Beijing-Tianjin urban agglomeration, analyzing the analytical evolution characteristics of regional ecosystem services, and exploring the driving roles of regional natural and social factors on ecosystem services, this study provides scientific guidance and decision basis for the future ecological environmental protection and planning strategy formulation of the Beijing-Tianjin urban agglomeration.