Dynamics of aeolian desertification and its driving forces in the Horqin Sandy Land, Northern China

Abstract

Aeolian desertification is one of the most serious environmental and socioeconomic problems in arid, semi-arid, and dry subhumid zones. Understanding desertification processes and causes is important to provide reasonable and effective control measures for preventing desertification. With satellite remote sensing images as data source to assess the temporal and spatial dynamics of desertification from 1975 to 2010 in the Horqin Sandy Land, dynamic changes of aeolian desertification were detected using the human-machine interactive interpretation method. The driving factors of local desertification were analyzed based on natural and socioeconomic data. The results show that aeolian desertified land in the study area covered 30,199 km(2) in 2010, accounting for 24.1% of the study area. The total area of aeolian desertified land obviously expanded from 30,884 km(2) in 1975 to 32,071 km(2) in 1990, and gradually decreased to 30,199 km(2) in 2010; aeolian desertified land represented an increasing trend firstly and then decreased. During the past 35 years, the gravity centers of desertified lands that are classified as extremely severe and severe generally migrated to the northeast, whereas those that are moderate and slight migrated to the northwest. The migration distance of severely desertified land was the largest, which indicated the southern desertified lands were improved during the last few decades. In addition, the climatic variation in the past 35 years has been favorable to desertification in the Horqin Sandy Land. Aeolian desertified land rapidly expanded from 1975 to 1990 under the combined effects of climate changes and unreasonable human activities. After the 1990s, the main driving factors responsible for the decrease in desertification were positive human activities, such as the series of antidesertification and ecological restoration projects.

Using Modified Remote Sensing Imagery to Interpret Changes in Cultivated Land under Saline-Alkali Conditions

“…Given the logarithm, the discriminant function can be expressed as: Then the center of gravity migration model was used to describe the overall intensity of change as well as the spatial variation characteristics of different degrees of the saline-alkali land. The spatial migration of the gravity center was demonstrated by the change in gravity center coordinate [16][17][18]. The gravity center coordinate was calculated as:…”

Detecting Sustainability of Desertification Reversion: Vegetation Trend Analysis in Part of the Agro-Pastoral Transitional Zone in Inner Mongolia, China

“…Mobile, semi-mobile, semi-fixed, and fixed are four grades of sand land corresponding to extremely severe, severe, moderate, and slight degrees of desertification [25]. The types and areas of sand land were provided by previous investigation [15,26]. The area is located in the southeast of Inner Mongolia, and is part of the Agro-pastoral Transitional Zone in Northern China; and (c) it was divided into agricultural zones (AZ), semi-agricultural and semi-pasturing zones (APZ), pasturing zones (PZ), and coal mining zones (CM) in this study.…”

“…Mobile, semi-mobile, semi-fixed, and fixed are four grades of sand land corresponding to extremely severe, severe, moderate, and slight degrees of desertification [25]. The types and areas of sand land were provided by previous investigation [15,26]. …”

Change of Soil Bacteria Diversity between Desertification and Restoration

“…1a[14]). Among those soil zones, aeolian sandy soil is widely distributed, and it can be found almost all the continents in the world [15], [16]. Aeolian sandy soil has some common characters compared with desert, but its development and utilization potential is larger, as long as treat it properly, it is possible for the recovery of aeolian sandy land.…”