关键词: 荒漠化, 分区, 时空演变, 荒漠化防治, 重心迁移轨迹, 遥感监测, 中国

Abstract:

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 Macau) 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.

Key words: desertification, zonation, spatiotemporal evolution, desertification prevention, remote sensing monitoring, China