内蒙古生态环境敏感性综合评价

针对内蒙古土地沙化、土壤侵蚀、土壤盐渍化和生物多样性减少等区域自然环境演变过程中出现的生态问题,采用遥感和地理信息系统技术,构建敏感性评价指标体系与评价模型,对内蒙古生态环境敏感性进行综合研究,定量揭示研究区生态环境敏感性程度和空间分布特征.结果表明:土地沙化不敏感区、极敏感区分别占研究区面积35.9%和10.1%;土地沙化敏感性等级高的区域集中分布在内蒙古辖区内主要沙漠边缘和沙地;土壤基质多为沙粒、冬春季节多大风且植被覆盖度较低是土地容易发生沙化的主要原因.土壤侵蚀轻度、中度和高度敏感区分别占研究区面积的43.9%、30.2%和19.2%;受降水空间差异影响,土壤侵蚀敏感性等级自东南向西北呈逐步下降趋势.土壤盐渍化不敏感区、极敏感区分别占研究区面积的57.6%和14.6%,盐渍化明显地区主要分布在内蒙古西北部和东部;蒸发量远大于降水量,人类活动影响较明显,是土壤盐渍化高发的主要原因.生境不敏感、高度和极敏感区分别占研究区面积的30.5%、25.1%和10.6%,敏感性等级高的区域主要分布在大小兴安岭地区;这些区域水热条件相对较好,植被覆盖度高,物种数量较为丰富,是生物多样性重点保护区域.综合生态环境高度和极敏感区分别占研究区面积的27.9%和9.6%;敏感性等级高的区域位于内蒙古中北部,等级较低的区域位于内蒙古西北、东北和东南部.

Comprehensive evaluation of eco-environmental sensitivity in Inner Mongolia,China

Using the integrated approach of GIS and RS technology, four factors including land desertification, soil erosion, soil salinization and biodiversity reduction were selected to establish the evaluation model of eco-environmental sensitivity in the present study. This paper analyzed the eco-environmental sensitivity and revealed its spatial characteristics in a quantitative way. The insensitive and extremely sensitive areas of land desertification made up 35.9% and 10.1% of the study area (1.183million square km), respectively. The surrounding areas of desertification in Inner Mongolia were the most environmentally sensitive regions. This was due to strong wind in winter and spring in these areas, and the soil mainly consists of sand and was seldom covered by vegetation. The slight, moderate and highly sensitive areas of soil erosion comprised about 43.9%, 30.2% and 19.2%, respectively. The trend of soil erosion sensitivity decreased gradually from Southeast to Northwest of Inner Mongolia, which was mainly a result of the vertical dropping slopes and spatial variation of precipitation. The insensitive and extremely sensitive areas of soil salinization made up 57.6% and 14.6%, respectively. The northwestern and eastern parts of Inner Mongolia were the most environmentally sensitive areas. The primary causes were negative impacts of arid climate and human activities. The insensitive, highly and extremely sensitive areas of bio-inhabitation comprise 30.5%, 25.1% and 10.6%, respectively. Highly sensitive areas are located in the northeastern parts of Inner Mongolia. The reason was that species richness was positively correlated with precipitation and vegetation cover in these areas. The highly and extremely sensitive areas of comprehensive eco-environment made up 27.9% and 9.6%, respectively. The high and extremely sensitive areas were located in the moderate and northern parts, and the insensitive, slight and moderate sensitive areas in the northwestern, northeastern and southeastern parts of Inner Mongolia.