退化和恢复过程驱动的荒漠草地生态系统有机碳密度变化

荒漠草地是陆地生态系统的重要组成部分,研究退化和恢复荒漠草地生态系统碳密度的变化特征,是精确评估荒漠草地在全球气候变化中作用的关键,也能为中国碳达峰和碳中和提供数据支撑和理论依据.通过野外调查取样和室内分析,研究了腾格里沙漠南缘天然荒漠草地、重度退化荒漠草地和通过植被建设恢复良好的人工-天然荒漠草地的生态系统碳密度,主...

Changes of organic carbon density in desert steppe ecosystem driven by degradation and restoration

Desert grassland is an important component of the terrestrial ecosystem， the study of carbon density in degraded and restored desert grassland ecosystem is important to evaluate the role of desert grassland in global climate change. It can also provide data support and theoretical basis for peaking carbon dioxide emissions by 2030 and carbon neutralization by 2060 of China. Field investigation， sampling and laboratory analysis were carried out for natural， heavily degraded and restored desert grassland in the southeastern fringe of the Tengger Desert， China. Differences of the total organic carbon density， soil organic carbon density （SOCD）， shrubs biomass carbon density （BCD）， and herb BCD among three ecosystems were examined. The results showed that shrub （leaves， new branches， aging branches， standing-dead and roots） BCD， herbage （shoot and root） BCD and SOCD of 0-100 cm soil profile of typical desert grassland were 213.234 g m^-2 （17.688 g·m^-2， 8.035 g·m^-2， 59.163 g·m^-2， 21.732 g·m^-2 and 106.617 g·m^-2）， 84.269 g·m^-2 （12.192 g·m^-2 and 72.077 g·m^-2） and 2.517 kg·m^-2， respectively. The carbon loss of degraded desert grassland was serious， shrub BCD， herbage BCD and SOCD only accounted for 14.901%， 45.549% and 26.852% of natural desert grassland. Degraded desert grassland had strong carbon sequestration potential， shrub BCD， herbage BCD and SOCD of 0-100 cm soil profile of restored desert grassland increased significantly， they were 2.463 times， 5.305 times， and 2.392 times as much as that of degraded desert grassland， respectively. The total organic carbon density increased by 1.152 kg·m^-2. SOCD of 0-20 cm soil profile and herbage BCD have reached the level of typical desert grassland， however， there was a large carbon sequestration potential （0.916 kg·m^-2）. Our study suggests that the desert and desertification area in China has great carbon sequestration potential， reasonable restoration measures is important strategy to increase carbon storage of desert grassland， alleviate the increase of CO₂ concentration and mitigate global climate change.