城市边缘区生态脆弱性时空演变——以大连市甘井子区为例

以1998年的土地利用数据和2003、2007、2013 SPOT5遥感数据等多元数据为基础,运用ESC模型结合空间分析法,线性加权方法计算社区的EVI值,并将甘井子区生态脆弱性划分为5个等级;以及运用二乘算法计算变化斜率,F值测算变化显著性,将变化斜率和变化显著性分为4个等级,研究大连市甘井子区1998—2013生态脆弱性的时空分异。结果表明:(1)从城市边缘区生态脆弱性等级分布特征来看,城市边缘区生态环境呈现出相同等级聚集,以邻近沙河口区社区为中心,相邻等级呈现出明显的辐射状,东西方向差异明显的特征。(2)从社区间生态脆弱性差异的角度来看,甘井子内部各社区生态状态差异显著。邻近市区的社区生态脆弱性变化显著生态环境迅速恶化,平均EVI由0.62增加至0.73,变化显著性指数为2.26。远离市区的部分社区生态环境变化不大,生态环境保持良好状态。部分社区EVI变化值呈现负增长,生态逐渐恢复。(3)从城市边缘区生态脆弱性整体变化趋势来看,1998—2013年间甘井子区的生态脆弱性变化与城市化发展速度密切相关,以2007年为节点,1998—2007年平均变化斜率指数为0.51,2007—2013年平均变化斜率指数为0.19,呈现出先快后慢的下降趋势。

Urban fringe area ecological vulnerability space-time evolution research: the case of Ganjingzi District, Dalian

Based on the land use data of 1998 and the remote sensing data of 2003, 2007, and 2013 SPOT5, the Ecological Vulnerability Index (EVI) value of the communities was calculated using the Exposure Susceptibility Coping Capacity (ESC) model combined with spatial analysis and linear weighting, and the ecological vulnerability of the Ganjingzi area was divided into five grades. To establish the evaluation index system, the change slope was calculated using the multiplication method. When the F value was significant, the change slope and significance were divided into four grades. Temporal distribution of ecological fragility in Ganjingzi District of Dalian, from 1998 to 2013, was also studied. The results were as folloes:(1) From the perspective of the distribution characteristics of ecological vulnerability in urban fringe areas, the ecological environment of the urban fringe area showed the same level of aggregation, and the neighborhood adjacent to the Shahekou District showed a distinct radial pattern, with obvious differences between the east and the west. (2) From the perspective of the ecological vulnerability of the communities, the ecological status of the communities within Ganjingzi District was significantly different. The ecological vulnerability of the communities adjacent to the urban area was remarkable, and the ecological environment was rapidly deteriorating. The mean EVI increased from 0.62 to 0.73. The change index, for significant differences, was 2.26. The ecological environments of some communities distant from the urban areas did not change remarkably, and were maintained in a good condition. In some communities, changes in EVI showed negative growth and the ecological environments gradually recovered. (3) From the urban fringe ecological vulnerability of the overall trend of change, the change of ecological vulnerability in Ganjingzi District between 1998 and 2013 was closely related to the speed of urbanization. With 2007 as the node, the average change or slope index in 1998-2007 was 0.51 and that in 2007-2013 was 0.19, showing a slow down after the first slow trend.