摘要:为探究城镇用地空间扩展对景观生态风险的影响，以南昌市为例，运用遥感、GIS及数理统计的方法，借助城镇扩展强度指数研究了南昌市2000-2017年城镇空间扩展的时空变化特征，构建了景观生态风险指数，以3 km×3 km的单元网格进行系统采样，探究城镇扩展下南昌市景观格局的动态变化和景观生态风险，最后基于地理加权回归（GWR）模型，定量分析2000-2017年南昌市城镇空间扩展与景观生态风险之间的耦合关系。结果表明：（1）2000-2017年，南昌市城镇用地增加了247.56 km²，年均扩展速率达17.75 km²，其中2000-2005年扩展最快，呈现出剧烈扩展的态势，扩展强度达到0.55。城镇扩展主要沿正北和西北方向扩展，分布在青山湖区、南昌县、新建区等，总体上呈快速扩展趋势；（2）南昌市景观格局以耕地为主，建设用地快速扩张，耕地、林地、草地面积持续减少，土地利用的景观格局指数反映此期间人类活动的干扰程度加剧，景观斑块数量增加，整体破碎度提高。借助地统计分析方法，计算得到南昌市景观生态风险由2000年的0.1354上升至2017年的0.1420，景观生态风险呈逐渐升高的趋势；（3）2000-2017年，城镇用地面积与景观生态风险、城镇空间扩展强度指数和景观生态险变化值之间，都呈现负相关影响，后者相关性在减弱。回归系数的空间分布上，由中部向外逐渐升高，低值位于城镇扩展较快的南昌市区，城镇的快速扩展使城镇用面积大幅增加，景观破碎度、损失度降低，景观生态风险随之降低；高值出现在进贤县、安义县等经济发展缓慢的地区，城镇用地扩展幅度小，扩展边界斑块破碎度大，分离度上升，景观生态风险增加。研究结果为促进城市建设与生态环境保护的相互协调，正确评价人类活动对城市生态系统的影响，以及南昌市的可持续发展和科学管理提供借鉴。



Abstract:This paper introduced the urban expansion intensity index to study the spatial and temporal variation characteristics of urban spatial expansion in Nanchang City from 2000 to 2017. Then, the 3 km×3 km unit grid was systematically sampled to construct the landscape ecological risk index to explore dynamic changes in the landscape pattern and landscape ecological risk. Finally, by using the geographic weighted regression (GWR) model, the relationship between urban spatial expansion and landscape ecological risk in Nanchang City from 2000 to 2017 was quantitatively analyzed to explore the impact of urban land expansion on landscape ecological risk. The results showed that:(1) From 2000 to 2017, urban land use in Nanchang increased by 247.56 km², with an average annual expansion rate of 17.75 km². Among them, the fastest expansion strength was 0.55 in 2000-2005, showing a dramatic change. The urban expansion mainly expanded to the north and northwest, and was distributed in the Qingshan Lake District, Nanchang County, and Xinjian County, among others, which showed a rapid expansion trend; (2) The landscape pattern of Nanchang City was dominated by cultivated land, and the construction land was expanding rapidly. The area of cultivated land, forest land, and grassland continued to decline, and the landscape pattern index of land use reflected that the degree of disturbance of human activities increased during the period, the number of landscape patches increased, and the overall fragmentation increased. By using the geostatistical analysis method, the ecological risk of Nanchang City increased from 0.1354 to 0.1420 between 2000 and 2017, and the ecological risk gradually increased. (3) From 2000 to 2017, there was a negative correlation between urban land area and landscape ecological risk, the urban spatial expansion intensity index, and the landscape ecological risk change value, with the latter weakening. The spatial distribution of the regression coefficient gradually increased from the central part to the outside, and the low value was located in the Nanchang urban area where the urban expansion was relatively fast. The rapid expansion of the urban area has greatly increased the urban area, and the degree of fragmentation and loss degree have been reduced. Ecological risks are reduced. High values occurred in areas with slow economic development, such as Jinxian County and Anyi County. With a small extend of urban land use and large degree of extended boundary patches, the ecological risk of the landscape increased. The research results could promote the coordination between urban construction and ecological environmental protection, correctly evaluate the impact of human activities on urban ecosystems, and provide references for sustainable development and scientific management in Nanchang.





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