Spatio-Temporal Development of Vegetation Carbon Sinks and Sources in the Arid Region of Northwest China

Qifei Zhang; Yaning Chen; Zhi Li; Congjian Sun; Yanyun Xiang; Zhihui Liu

doi:10.3390/ijerph20043608

Spatio-Temporal Development of Vegetation Carbon Sinks and Sources in the Arid Region of Northwest China

Int J Environ Res Public Health. 2023 Feb 17;20(4):3608. doi: 10.3390/ijerph20043608.

Authors

Qifei Zhang^{1

2

3}, Yaning Chen², Zhi Li², Congjian Sun^{1

2

3}, Yanyun Xiang⁴, Zhihui Liu¹

Affiliations

¹ School of Geographical Sciences, Shanxi Normal University, Taiyuan 030031, China.
² State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
³ Research Center of Ecology and Environment in the Middle Reaches of the Yellow River, Shanxi Normal University, Taiyuan 030031, China.
⁴ School of Public Administration, Shanxi University of Finance and Economics, Taiyuan 030006, China.

Abstract

Drylands, which account for 41% of Earth's land surface and are home to more than two billion people, play an important role in the global carbon balance. This study analyzes the spatio-temporal patterns of vegetation carbon sinks and sources in the arid region of northwest China (NWC), using the net ecosystem production (NEP) through the Carnegie-Ames-Stanford approach (CASA). It quantitatively evaluates regional ecological security over a 20-year period (2000-2020) via a remote sensing ecological index (RSEI) and other ecological indexes, such as the Normalized Difference Vegetation Index (NDVI), fraction of vegetation cover (FVC), net primary productivity (NPP), and land use. The results show that the annual average carbon capacity of vegetation in NWC changed from carbon sources to carbon sinks, and the vegetation NEP increased at a rate of 1.98 gC m^-2 yr^-1 from 2000 to 2020. Spatially, the annual NEP in northern Xinjiang (NXJ), southern Xinjiang (SXJ) and Hexi Corridor (HX) increased at even faster rates of 2.11, 2.22, and 1.98 gC m^-2 yr^-1, respectively. Obvious geographically heterogeneous distributions and changes occurred in vegetation carbon sinks and carbon sources. Some 65.78% of the vegetation areas in NWC were carbon sources during 2000-2020, which were concentrated in the plains, and SXJ, the majority carbon sink areas are located in the mountains. The vegetation NEP in the plains exhibited a positive trend (1.21 gC m^-2 yr^-1) during 2000-2020, but this speed has slowed since 2010. The vegetation NEP in the mountain exhibited only intermittent changes (2.55 gC m^-2 yr^-1) during 2000-2020; it exhibited a negative trend during 2000-2010, but this trend has reversed strongly since 2010. The entire ecological security of NWC was enhanced during the study period. Specifically, the RSEI increased from 0.34 to 0.49, the NDVI increased by 0.03 (17.65%), the FVC expanded by 19.56%, and the NPP increased by 27.44%. Recent positive trends in NDVI, FVC and NPP have enhanced the capacity of vegetation carbon sinks, and improved the eco-environment of NWC. The scientific outcomes of this study are of great importance for maintaining ecological stability and sustainable economic development along China's Silk Road Economic Belt.

Keywords: FVC; NDVI; RSEI; climate change; northwest China; vegetation carbon sinks and sources.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbon
Carbon Sequestration*
China
Climate Change
Ecosystem*
Humans
Telemetry

Substances

Carbon

Grants and funding

This research was funded by the Natural Science Foundation of Xinjiang Uygur Autonomous Region (2021D01E02) and the National Key Research and Development Program (2019YFA0606902).