西南生态安全屏障区由重庆、四川、贵州、云南、广西，及西藏部分地区和青海的部分地区组成，包括青藏高原、横断山区、云贵高原等地形地貌地区。该区域生态系统复杂多样，生物多样性、水资源、矿产资源等自然资源丰富，是长江、珠江、西南诸河的上游源头，对于维系中国东部和东南亚地区的生态和社会安全具有重要作用，是中国重要的生态安全屏障区。然而，该区域生态环境敏感脆弱，也是我国西部大开发建设的重点扶持区域。区域的城镇化发展会强烈干扰生态系统结构与功能，且可能会削弱区域的生态屏障作用。因此，针对西南生态安全屏障区城镇化及伴随而来的对区域生态系统的影响，并围绕区域生态环境持续发展和区域社会经济可持续发展的需求，该研究探讨以下四点关键问题：（1）屏障区城镇扩张的演变规律；（2）屏障区城镇化对区域植被变化的影响；（3）屏障区城镇化对区域景观格局变化的影响；（4）屏障区城镇化与生态系统服务的耦合关系。主要结果和结论如下： （1） 1990至2015年，屏障区的城镇人工建筑集中在区域东南部，主要分布在成渝城市群、黔中城市群、滇中城市群和北部湾城市群。屏障区整体的城镇扩张中心落在黔中城市群西部，并且逐渐北移。复合人工表面覆盖率指数的分析结果表明，屏障区约90%县区的城镇化以低人工表面密度区（人工表面覆盖率低于50%）的扩张为主，且大部分县区的城区和郊区虽然面积增长但人工表面覆盖率却降低。根据区域近25年的城镇空间扩张规律推测，屏障区的城镇化将会持续以低人工表面密度区的扩张为主。 （2） 不同时间尺度上，屏障区大部分地区的夜间灯光指数和归一化植被指数（NDVI）均表现出增长趋势，且二者的年均变化量在2000年后逐渐加快。然而，灯光覆盖区域（DN>0）的植被表现出明显的退化趋势。地理加权回归结果表明，灯光覆盖区灯光亮度的变化对NDVI变化的贡献率约为15%。而且，随着城镇化水平的提高，灯光亮度变化对NDVI变化的解释率逐渐增大。城市梯度上，城市外围的灯光亮度增加倾向于对NDVI产生正效应，然而城市中心的灯光亮度增加，倾向于对NDVI产生负效应，且越靠近城市中心，负效应越强。 （3） 1990至2015年，屏障区整体的景观格局变化较平缓。其中，2000至2010时段为全域水平上，景观变化最为剧烈的时段，该时段内区域的年均变化面积约为1%。各地类中以人工表面地类的变化最为活跃，而且其增长趋向于占用耕地。县域水平上，不同典型县区的景观格局变化差异明显，但各县区景观的格局具有相似性。典型县区的城市梯度上，城区和非开发区的斑块通常面积较大且呈聚集分布，而郊区和边缘区的斑块则面积偏小、类型丰富且形状复杂。此外，大部分典型县区的平均斑块面积均偏小（<0.50 km²），斑块分布较为破碎。 （4） 2000至2010年，屏障区约99%的区域的生态系统服务发生变化，屏障区总生态系统服务价值增长了约850.35亿元。自组织神经网络分析结果表明，城镇化进程中约95%县区的生态系统服务簇类型未发生变化，即大部分地区的生态系统服务之间的权衡和协同关系稳定。然而屏障区约80%县区的城镇化与生态系统服务仍处于低水平的耦合协调阶段。典型城镇的PANDORA模型评估表明，城市景观空间组分变化对生态系统服务的影响强于景观空间结构变化的影响，聚集且形状复杂的人工建筑斑块结构有助于减缓城镇建筑用地扩张对生态系统服务的负效应。 综上，目前屏障区城镇化对区域生态安全的影响更多的表现为负面影响。屏障区的城镇化以低人工表面密度区扩张为主导，伴随着局部的植被退化以及与生态系统服务耦合程度偏低等削弱区域生态屏障功能的问题。在应对策略方面，推荐以保障生态用地为主，合理规划城镇空间格局为辅助。

The Ecological Security Barrier Region of Southwest China (ESBR) consists of cities of Chongqing, Sichuan, Guizhou, Yunnan, Guangxi, and parts of Tibet and Qinghai Province. Geographically, ESBR includes the Qinghai-Tibet Plateau, Hengduan Mountains, and Guizhou Plateau, etc. Ecosystems of the ESBR are in high spatial heterogeneity, for instance, the biodiversity, water resources, mineral resources, and other natural resources of the region are very rich. Importantly, ESBR is also the headstream of Yangtze River, Pearl River, and many southwestern rivers. ESBR plays an important role in maintaining ecological and social securities for both eastern China and Southeast Asia. However, ESBR is sensitive and fragile in ecological environments, and it is also the fundamental area of China's Go-West Campaign. Over recent decades, the regional urbanization leads to significant changes in ecosystem structures of ESBR, consequently, weakens its ecosystem functions. Therefore, in view of the urbanization and its potential impact on ecosystems in ESBR, this study focuses on the following essential issues: (1) Evolutions of urban expansions in ESBR; (2) Effects of the urbanization on vegetations in ESBR; (3) Effects of the urbanization on ecosystem structures of ESBR; (4) Compounding effects of the urbanization on both ESBR and its ecosystem services. The main results and conclusions are summarized as follows. (1) From 1990 to 2015, the artificial surface of the ESBR was concentrated in the southeastern area, including Chengdu-Chongqing urban agglomeration, the Central Guizhou urban agglomeration and the Nanning-Beihai-Qinzhou-Fangchenggang urban agglomeration. The entire urban expansion center of ESBR fallen into the west of Central Guizhou, and gradually moved northward. The compounded artificial surface cover showed that the urbanization of about 90% of counties in ESBR was dominated by the low artificial surface density covering area (artificial surface cover is less than 50%). Urban lands and suburbans of most counties were increased with the corresponding artificial surface cover rate decreasing in ESBR. According to the urban expansion trend of the area for the past 25 years, the urbanization of the ESBR would continue to be dominated by the expansion of the low artificial surface density covering area. (2) The nighttime light and normalized difference vegetation index (NDVI) in ESBR showed growth trends at multiple time-scales, and average annual changes of them were gradually accelerated after 2000. However, the vegetation in the light-covered area showed a significant degradation trend. The results of geographically weighted regression revealed that changes of light brightness in the light-covered area contributed about 15% in the change of NDVI. And with the upgrading of the urbanization level and size, the contribution of the light brightness changes on NDVI has also increased accordingly. On the urban gradient, the increase of light brightness in the periphery of the city tended to have a positive effect on NDVI, and as close to the city center, the increase of light brightness tended to have a stronger negative effect on NDVI. (3) The landscape pattern in the ESBR changed slightly from 1990 to 2015. The annual change of the ESBR (rate of ~1%) in periods between 2000 and 2010 was most apparent in the integral of 25 years. The artificial surface was the most active land use types, and its growth tended to occupy farmland. At the county scale, changes of landscape patterns in each typical county were distinct, while landscape patterns of counties showed less different. On the urban gradient, patches of the urban area and non-development areas were usually large and clustered, while patches in suburban and marginal areas were always small, diverse and with a complex shape. It is noteworthy that the average patch area in most typical counties was quite small (<0.50 km2) and the distribution of patches is relatively fragmented. (4) From 2000 to 2010, ecosystem services of about 99% region of ESB had changed, and the value of total ecosystem services in ESBR increased by about ￥85.035 billion. However, the results of self-organizing neural network analysis showed that types of ecosystem service clusters in about 95% of counties were still constant. This also represented trade-offs and synergies between ecosystem services of ESBR were with minor changes. However, the coupling degree between urbanization and ecosystem services in 80% of counties were in low-level. PANDORA model indicated that the effect of landscape spatial component changes on ecosystem services was stronger than that of landscape spatial structure. Moreover, urban expansion pattern with aggregated artificial surface patches and complex shapes could help to slow down the negative effects of urban expansion on ecosystem services. In conclusion, the urbanization of ESBR owned a negative impact on the regional ecosystem. The urbanization of ESB was mainly guided by the expansion of the low artificial surface density covering area, which was accompanied by the vegetation degradation, the fragmentation of the habitat landscape, and low-level coupling relationship between urbanization and ecosystem services. All of the above phenomena might accelerate the weakening of the ecological security barrier function of ESBR. Therefore, we recommended to conserve the ecological land in ESBR and make rational plans for the city spatial pattern in the region.