Drivers and Environmental Impacts of Vegetation Greening in a Semi-Arid Region of Northwest China since 2000

Abstract

The dynamics of terrestrial vegetation have changed a lot due to climate change and direct human interference. Monitoring these changes and understanding the mechanisms driving them are important for better understanding and projecting the Earth system. Here, we assessed the dynamics of vegetation in a semi-arid region of Northwest China for the years from 2000 to 2019 through satellite remote sensing using Vegetation Index (VI) data from the Moderate Resolution Imaging Spectroradiometer (MODIS), and analyzed the interannual covariation between vegetation and three climatic factors—air temperature, precipitation, and vapor pressure deficit (VPD)—at nine meteorological stations. The main findings of this research are: (1) herbaceous land greened up much more than forests (2.85%/year vs. 1.26%/year) in this semi-arid region; (2) the magnitudes of green-up for croplands and grasslands were very similar, suggesting that agricultural practices, such as fertilization and irrigation, might have contributed little to vegetation green-up in this semi-arid region; and (3) the interannual dynamics of vegetation at high altitudes in this region correlate little with temperature, precipitation, or VPD, suggesting that factors other than temperature and moisture control the interannual vegetation dynamics there.

The grassland carbon cycle: Mechanisms, responses to global changes, and potential contribution to carbon neutrality

“…However, several studies have demonstrated that grassland and semi-arid ecosystems contribute significantly to the increased global C sink in recent decades [16] , which is related to the greening trend in many dryland ecosystems that has been observed since the 1980s [11] . For example, in the semi-arid regions of China, land dominated by herbaceous plants has greened up much more than forests over the last 20 years [ 24 , 25 ]. In Australia, the prevalent La Niña conditions from 1981 to 2011 caused consecutive seasons with increased precipitation and thus vegetation cover expansion [17] .…”