Carbon use efficiency of terrestrial ecosystems in desert/grassland biome transition zone: A case in Ningxia province, northwest China
Carbon use efficiency of terrestrial ecosystems in desert/grassland biome transition zone: A case in Ningxia province, northwest China
复制标题
荒漠/草原生物群落过渡带陆地生态系统碳利用效率：以宁夏为例
DOI：
10.1016/j.ecolind.2020.106971
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发表时间：
2021-01-01
影响因子：
6.9
通讯作者：
Wu, Hongyue
中科院分区：
文献类型：
--
作者：
Du, Lingtong;Gong, Fei;Wu, Hongyue
陆地生态系统在全球碳循环中扮演着重要的角色，碳循环的反馈将对未来气候变化产生重要影响。值得注意的是，南半球的半干旱生物群落在过去30年中推动了全球碳汇异常。然而，荒漠/草原过渡带作为干旱半干旱生物群落的一部分，其碳利用效率（CUE）对气候变化和人类活动的响应机制尚不清楚。基于2001 - 2017年中分辨率成像光谱仪（MODIS）数据估算的陆地生态系统CUE，研究了典型荒漠/草原生物群落过渡带宁夏的CUE时空特征。通过偏相关分析，探讨了影响该地区生态环境和气候变化的主要驱动因子。结果表明，荒漠/草原过渡带陆地生态系统的CUE大于0.5，这是许多生态模型中定义的CUE的恒定值。然而，即使它们位于同一气候带，CUE也因生态系统类型而异。2001-2017年，年CUE呈下降趋势，且在像元尺度上，大部分CUE未来将持续下降，这可能主要是由土地利用变化引起的。通过对不同生境条件的比较发现，在同一生态系统中，较低的郁闭度和水分胁迫可以提高植物的CUE，这表明植物在逆境中可以提高其将大气碳转化为陆地生物量的效率。CUE与生态系统过程中的净初级生产力（NPP）和自养呼吸（Ra）显著相关，水分胁迫（降水量减少）和热胁迫（温度升高）均能提高CUE，但温度对不同生态系统的影响不同。
Terrestrial ecosystems play a critical role in the global carbon cycle and the feedbacks of carbon cycle will significantly impact future climate change. It's worth noting that semi-arid biomes in the Southern Hemisphere have driven the global carbon sink anomaly over the past 30 years. However, how does the desert/grassland biome transition zone, a part of arid and semi-arid biomes, respond to climate change and anthropogenic ac-tivities in carbon use efficiency (CUE) is still unclear. Therefore, based on the CUE of terrestrial ecosystem estimated by the moderate resolution imaging spectroradiometer (MODIS) data from 2001 to 2017, the spatial and temporal characteristics of CUE in Ningxia province, a typical desert/grassland biome transition zone, were studied. The main driving factors in climate and ecosystem were also investigated by partial correlation analysis. Results showed that the CUE of terrestrial ecosystems in desert/grassland biome transition zone is higher than 0.5, a constant value of CUE defined in many ecological models. However, the CUE varies with the ecosystem types even when they are located in the same climatic zone. There is a decreasing trend of annual CUE in the period of 2001-2017 and most of them will persistently decrease in future at pixels scales, which could be mainly caused by the land use change. Comparing the habitat conditions, we found the lower canopy density and water stress could increase the CUE in the same ecosystem, which indicates the plant could increase their efficiency of transforming carbon from the atmosphere to terrestrial biomass in adverse environment. Finally, the CUE significantly correlated to net primary productivity (NPP) and autotrophic respiration (Ra) in ecosystem processes, meanwhile water stress (lower precipitation) and heat stress (higher temperature) could increase the CUE, but the temperature has variable impacts in different ecosystem.