基于GIS的沿海地区生态安全时空测度与演变——以大连市瓦房店为例

Spatial-temporal assessments and evolution research of coastal eco-security based on gis-a case study of wafangdian county-level city

以大连瓦房店市2000年、2005年和2010年Landsat TM遥感影像(轨道号为120/32,120/33)作为数据源,在景观格局分析的基础上,基于压力-状态-响应(P-S-R)框架构建沿海地区生态安全评价体系,在GIS格网技术下量化多源数据,创建区域生态安全格网数据库,采用加权-模糊隶属度评价方法进行生态安全状态评价,并通过空间统计学方法对研究区生态安全格局时空演变进行分析,揭示沿海地区生态安全时空演变特点。结果表明:12000—2010年瓦房店市生态安全指数平均值分别为0.4636、0.3878和0.3980,说明研究区生态安全恶化后又有缓升趋势,但西部沿海地区生态安全依然需要重视。2Moran's I从2000年到2010年分别为0.9015、0.8738和0.8703,表明瓦房店市生态安全指数在空间上存在较强的正相关关系,生态安全格局表现为高值区域倾向于与生态安全程度高的区域相毗邻,而生态安全程度低的区域倾向于与生态安全程度低的区域毗邻,2000—2005年表现极为明显。32000—2010年瓦房店市生态安全指数的块金值分别为0.0030、0.0007和0.0009,表明非结构因素对研究区生态安全空间分布影响效应逐渐增强,这与10年来瓦房店城市建设用地扩张、人类活动频繁的实际情况相符。CO/(CO+C)值也是先增加后减少,表明非结构因素对研究区生态安全空间分异的影响效应先增强后减弱,2005年以来随着大连市土地政策的实施与管理,城镇建设、人类活动等非结构因素对生态安全演变影响有所消减。

In this study, taking the Landsat TM remote sensing images （track No. 120/32, 120/33） of Wafangdian County-level City in 2000, 2005 and 2010 as the data sources, the coastal ecological security evaluation system was established on the basis of landscape pattern analysis and pressure-state-response （P-S-R） framework. Grid database of coastal eco-security assessment was created by quantitative multi-source data with GIS grid technology. Eco-security status was estimated by the use of the weighted-fuzzy membership degree method. Temporal and spatial evolution of eco-security pattern was analyzed through spatial statistical methods in order to reveal evolution features of coastal region ecological safety as well. The results showed as follows： 1） The ecological safety index of Wafangdian County-level City from 2000 to 2010 was 0.4636, 0.3878 and 0.4636, respectively, which demonstrated eco-security situation had a slight improvement after deterioration, but we should pay more attention to prefect the ecological status in western coastal district. 2）Moran＇s I from 2000 to 2010 was 0.9015, 0.8738 and 0.8703, respectively, which indicated there was a significant correlation of spatial evolution in the space. The characteristic of ecological safety pattern was that areas with high value was inclined to be close to the regions of better ecological eco-security status, while the low degree of eco-security status presented adverse tendency, which performed extremely obvious from 2000 to 2005. 3）The nuggets of eco-security index in Wafangdian County-level City was 0.0030,0.0007 and 0.000903, respectively, which showed the non-structural factors played an ever-increasing role in spatial distribution of ecological safety in the study area, which was consistent with the actual conditions of urban construction land expansion and frequent human activities in the past decade. The change about value of C0/（C0＋C） decreased as the speed increased initially and decreased afterwards, which reflected the impact of non-structural factors on the space differentiation of ecological security had experienced a consistent change trend. With the implementation of the land policy and management of Dalian City, the influence from non-structural factors such as urban construction and human activities on eco-security evolution has been cut down since 2005.