LANZHOU, July 2 (Xinhua) -- A new study by Chinese scientists offers valuable insights for regional desertification control and ecological restoration, filling a gap in long-term, high-temporal-resolution reconstruction of desertification using annual rings from a specific desert shrub.
This study was conducted by researchers at the Northwest Institute of Eco-Environment and Resources (NIEER) under the Chinese Academy of Sciences. Its findings have been published in several journals, including Journal of Environmental Management, Journal of Forestry Research, Catena, and Gondwana Research, according to the institute.
Assessing global desertification risk and reconstructing long-term evolution processes are crucial for formulating regional control strategies and implementing the United Nations Convention to Combat Desertification (UNCCD). However, understanding of large-scale desertification risk remains incomplete, and there are few studies on long-term, high temporal resolution reconstructions of desertification history, according to Xiao Shengchun, a researcher at NIEER and leader of the study team.
He noted that without a unified approach, it remains challenging for researchers to gain a comprehensive picture of global desertification patterns and to identify the predominant drivers of this phenomenon at a planetary scale.
"Therefore, we launched this study to fill these gaps, aiming to advance understanding of desertification mechanisms and support ecological restoration," Xiao said.
The team incorporated annual-ring information from a desert shrub into the analysis. According to Xiao, certain desert shrubs, like trees, form distinct annual rings that record moisture, climate, and environmental conditions of each growth year.
Using multi-source remote-sensing data, the researchers assessed global desertification risk, screened optimized indicators applicable to desert regions from various vegetation indices, as well as built a reconstruction framework with the desert shrub's tree-ring chronology, vegetation index and desertification index.
Applying this framework, they conducted reconstruction studies on the spatiotemporal evolution patterns and processes of historical desertification in China's Tengger Desert and Ulan Buh Desert.
The results show that 43.09 percent of global land areas are at high risk of desertification, while low-risk and medium-risk zones account for 35.52 percent and 21.39 percent, respectively.
Regions at high and extreme risk are mostly concentrated in the Mediterranean, East Africa, East Asia, South Africa, South America, and West Africa. Globally, climate quality emerged as the primary driver of desertification risk, followed by vegetation quality and management quality, showed the study.
The study also found that, in arid desert regions with high bare-ground coverage, the Perpendicular Vegetation Index responds more directly to changes in greenness and provides more stable data. It outperforms other indices in reconstruction stability, demonstrating stronger robustness and reliability, making it the optimal indicator for long-term vegetation dynamic reconstruction in arid desert regions.
In the northern margin of the Ulan Buh Desert, desertification showed an overall decreasing trend, while the southern margin remained relatively stable. The study found that climatic factors primarily drive desertification in the north, whereas in the south, it is mainly influenced by human activities, with precipitation playing a supplementary role.
"Next, our team will extend studies to other similar regions of China to further reveal the spatiotemporal pattern evolution and driving mechanisms of desertification, providing scientific support for the country's Three-North Shelterbelt Forest Program and other desertification prevention and ecological restoration efforts," Xiao said. ■
