评估不同土地利用方式下生态风险程度并揭示其时空演变规律,对于优化土地利用方式、加强生态保护具有重要意义。借助遥感影像解译得到土地利用数据,以行政村为研究单元,基于景观生态学思想构建生态风险评价体系对南昌市2005—2017年土地利用生态风险进行评估。在此基础上,在Geoda,GS+平台的支持下对生态风险的时空演变特征展开剖析。结果 发现:(1)南昌市土地利用生态风险以中低风险为主,但是各风险等级总体呈上升趋势,高风险区主要位于西南边陲和濒临鄱阳湖区域,中心城区生态风险有逐渐增长趋势;(2)2005—2017年,模型拟合基台值由0.713下降至0.604,生态风险具有一定的空间变异性,在45°方向上,变异程度最大;(3)生态风险空间Moran's I值分别为0.451 9,0.424 3,0.401 0,呈正相关性,局部以HH和LL型聚集为主,HH型以组团状分布于新建区的石岗镇与松湖镇、濒临鄱阳湖区域,LL型以带状分布于城市远郊及交错地带。研究结果可为南昌市城市景观生态建设和土地利用优化提供参考依据。
Assessing the degree of ecological risk under different land use patterns and revealing its temporal and spatial evolution processes are of great significance for optimizing land use patterns and strengthening ecological protection. In this paper, the land use data were obtained by remote sensing image interpretation. The administrative village is taken as the research unit. The ecological risk assessment system is constructed based on the landscape ecology theory to evaluate the ecological risk of land use in Nanchang City from 2005 to 2017. On this basis, with the support of Geoda and GS+ platform, the spatial-temporal evolution characteristics of ecological risk are analyzed. The results show that:(1)the ecological risk of land use in Nanchang City is mainly low and medium risk, but the area of each risk grade is generally rising; the high-risk area is mainly located in the southwestern border and the Poyang Lake area, the ecological risk in the central urban area is gradually increasing;(2)from 2005 to 2017, the model fitting base value decreased from 0.713 to 0.604, and the ecological risk had a certain spatial variability, in the 45° direction, the degree of variation was the largest;(3)the ecological risk space Moran's I values are 0.451 9, 0.424 3, and 0.401 0, respectively, showing a positive correlation; the HH and LL types mainly distribute in the local area; the HH type distribution in the group of Shigang Town and Songhu Town in the Xinjian District, and near the Poyang Lake area; the LL type distributes in the outer suburbs and the interlaced areas of the city. The research results can provide reference for urban landscape ecological construction and land use optimization in Nanchang.
