中国北方13省市区生态安全动态变化分析

为了寻求我国北方生态安全条件的土地利用/覆盖优化格局,加强区域生态安全研究,在GIS技术的支持下,利用景观分析和空间变异分析方法对北方13省(市、区)生态安全动态变化及其空间变异特征进行了分析。结果表明研究区生态安全指数具有较强的空间相关性。人类活动等随机因素对生态安全的作用强度在增大,但是结构性因素引起的空间相关仍然是该区生态安全空间分异的决定性因素。10年间研究区生态环境质量整体表现出下降趋势;空间上,中西部地区生态安全程度低于东部地区;13个省(市、区)的生态安全指数的变化表现为三种类型:先升后降型、先降后升型和持续下降型。

The dynamic changes of ecological security in northern China

Regulation and rebuilding of landscape structure are the keys to redevelop the regional safe ecological pattern. The eco-environment of the 13 provinces in northern China is relatively fragile. In order to understand the eco-environment feedback mechanism and seek a way to optimize landuse/cover spatial pattern under ecological security, the temporal and spatial dynamic changes of the ecological security in northern China during the 11-year period from 1989 to 1999 is analyzed based on the landscape ecology theoretic, semivariogram and GIS in this paper. The results show that: (1)The eco-environmental quality in the study area showed an obvious decreasing trend. The eco-environmental quality in the areas with high ecological security decreased more slowly on the whole. The main reasons are that the eco-environment is better,flexible and steady. So it has higher capability to resist the outside disturbances. (2)The level of ecological security in the east region was more secure than that in the west and central regions.For each sub-region, the level of ecological security in Northwest China was the lowest; Inner Mongolia was secondly; Shaanxi and Shanxi provinces that lie in the Loess Plateau were in the third place; North China was higher than the above three sub-regions; and the three provinces in Northeast China were the highest. (3)The changes of the indexes of ecological security could be divided into three types: ①the indexes of the level of ecological security increased firstly and then decreased, including Beijing, Liaoning, Shanxi and Qinghai; ②the indexes of the level of ecological security decreased and then increased, including Heilongjiang, Jilin, Inner Mongolia, Ningxia; ③the indexes of the level of ecological security decreased continuously, including Tianjin, Hebei, Shaanxi, Gansu, and Xinjiang. During the ten years, the levels of ecological security decreased at different speeds except Northeast China.