Driving forces of agricultural expansion and land degradation indicated by Vegetation Continuous Fields (VCF) data in drylands from 2000 to 2015

Abstract

Drylands account for 41% of the world’s terrestrial surface, affect more than two billion people, and play a crucial role in global circulation and even global climate change. Therefore, the investigation of agricultural expansion and land degradation regions is a critical part of understanding the human-land coupling systems in dryland ecosystems. The specific distributions of agricultural expansion or land degradation in arid areas were obtained by using three indicators of global Vegetation Continuous Fields (VCF) data, in which expanding agriculture is usually characterized by tree canopy (TC) loss and short vegetation (SV) gain, while land degradation is characterized by a decrease in short vegetation and an increase in bare ground (BG). Assessing the partial correlation of natural or socioeconomic factors and indicators of agricultural expansion or land degradation while the structural equation model was established, we found that (1) the vegetation situation in the global arid region is relatively stable, and the normalized difference vegetation index (NDVI) value in the Asian arid region is increasing annually; (2) precipitation in the global arid region has a highly positive correlation with TC and a highly negative correlation with BG, while temperature is strongly correlated with SV except in arid areas; (3) both agricultural expansion and land degradation regions are dominated by natural factors, especially temperature; and (4) the control of socioeconomic factors is not closely related to the original land use/cover types in dryland regions.

Keywords

• Dryland
• Agricultural expansion
• Land degradation
• VCF
• Driving forces