中国荒漠化分区与时空演变

Zonation and Spatiotemporal Evolution of China's Desertification

荒漠化被列入威胁人类生存的十大环境与发展问题之一,中国作为世界上荒漠化严重的国家,荒漠化形势十分严峻。本文通过遥感手段,以中国陆域国土范围(除台湾、香港和澳门)的31个省、市、自治区为研究区域,对1975年、2000年与2017年研究区数据进行沙化、盐渍化、水蚀荒漠化专题因子时空演变的综合研究,根据地域分异、发生学及多级序列等原则将将中国划分为8个荒漠-荒漠化区,42个荒漠-荒漠化亚区和36个荒漠-荒漠化小区。以不同时期荒漠化土地类型图为依据,采用荒漠化面积变化量与荒漠化重心迁移轨迹指标进行荒漠化演化分析。为具体说明不同区域荒漠化程度,本研究根据一定时期内荒漠化土地面积增加或减少的百分比将荒漠化演化分为7种类型,通过分析得到不同荒漠化区域的时空演化及不重心迁移,据此提出中国荒漠化的重点治理目标区及防治建议。研究结果表明:①中国荒漠、荒漠化土地种类较多,重度荒漠化面积25.18×104km2,占荒漠化总面积的19.59%;②1975-2017年,中国荒漠化发生明显逆转,与1975-2000年相比,2000-2017年全国的荒漠化强度显著下降,原因是荒漠化加重区面积减少以及荒漠化减弱区面积增加;③1975-2000年与2000-2017年,各区内荒漠化重心点坐标迁移具有同向性。本研究在分析荒漠化土地分布、形成和演变机制的基础上,进行了荒漠化分区。通过对不同荒漠化地区的面积百分比变化的比较,得到了不同时期荒漠化的时空演化模式,并分析了荒漠化演化的特点和差异。

Land desertification is one of the most serious eco-environmental problems in the world, and is among the top ten environmental and development problems that threaten the survival of human beings. China has severe desertification, and desertification has greatly affected China’s eco-environment and social development. In this context, the research on desertification is of great significance to China. The evolution of desertification is mainly manifested in the change of desertification area, the area change, change of desertification types, vegetation change, and so on. In this paper, the 31 provincial regions of China(excluding Taiwan, Hong Kong, and Macao) were included as the study area. Remote sensing was utilized to study the spatiotemporal evolution of the thematic factors of desertification, salinization, and erosion-induced desertification. Following the principles of regional differentiation, genesis, and multi-level sequences, China was divided into 8 desertification zones, 42 desertification sub-regions, and 36 desertification communities.Based on the desertified land type maps of 1975, 2000 and 2017, we analyzed the desertification evolution by focusing on the changes in the area and gravity center of China’s desertification. According to the percentage of increase or decrease of desertified land area over a certain period of time, the evolution types of desertification can be divided into 7 categories. The present study reveals the current situation of China’s desertification, and analyzes the spatiotemporal evolution and the gravity center movements of different desertification regions. Next,the key target areas and management suggestions of desertification control in China were discussed. Our findings are as follows.(1) There are many kinds of deserts and desertified lands in China, of which the area of severe desertification is 25.18×104 km2, accounting for 19.59% of the total desertification area.(2) From 1975 to 2017,China’s desertification has been significantly reversed, and the dynamic characteristics of desertification in 1975-2000 differed from 2000-2017. The intensity of desertification in 2000-2017 significantly reduced as compared to 1975-2000, thanks to the decrease in aggravated areas and increase in weakened areas.(3) The migration value of desertification center of gravity can indirectly reflect the development trend and degree of dynamic change of desertification, the greater the migration, the more significant the difference of desertification change in this region, and the direction of center of gravity migration is the area where desertification area increases. The coordinate migration of desertification barycenter points in different periods has the same orientation.