摘要:热浪（Heat waves）是近年来频发的一种极端气候，其短期时间会影响生态系统植被健康并对生态系统碳通量产生长期负面影响，但其影响强度往往因生态系统类型而异。而内蒙古高原草甸草原属高纬度半干旱生态脆弱区，受气候变化影响显著，且正在遭受频繁热浪侵袭。在内蒙古呼伦贝尔草甸草原进行为期2年的野外原位模拟热浪控制实验，关注热浪对生态系统碳循环关键过程的影响和调节机制，并研究人类活动（刈割）与极端气候（热浪）对草甸草原碳通量的交互作用。结果表明，热浪处理显著降低了生态系统的土壤含水量，并显著降低草甸草原净碳交换（NEE）、生态系统呼吸（Re）和生态系统总生产力（GEP），分别为31%、1%和14%。然而，刈割处理下，能够有效降低热浪的负面影响，表现为热浪后草地恢复所需时间缩短了约1/3。同时，热浪后水分供给能缓解热浪对生态系统碳通量的滞后效应，并缩短生态系统所需的恢复时间。



Abstract:Heat wave (HW) is a type of extreme climate that has been occurring frequently in recent years. It affects the vegetation health of ecosystem in the short term and has the long-term negative influence on ecosystem carbon flux, but the intensity of its influence tends to vary depending on the type of ecosystem. The meadow grassland of the Inner Mongolia Plateau is a high-latitude semi-arid ecologically fragile area, which is significantly affected by climate change and is suffering from frequent heat wave. Therefore, this study conducted a two-year in-situ simulated heat wave control experiment in Hulunbuir meadow grassland of theInner Mongolia, focusing on the influence of heat wave on key processes of ecosystem's carbon cycle and the regulatory mechanism, and studying the interaction between human activities (mowing) and extreme climate (heat wave) on meadow grassland carbon flux. The results showed that heat wave treatment significantly reduced the soil water content of ecosystem, as well as net carbon exchange (NEE), ecosystem respiration (Re) and gross ecosystem productivity (GEP) of meadow grassland by 31%, 1% and 14%, respectively. However, the mowing treatment can effectively reduce the negative influence of heat wave, which is reflected in that time required for grassland recovery after the heat wave is shortened by 1/3. Meanwhile, water supply after heat wave can alleviate the legacy effect of heat wave on ecosystem carbon flux and shorten the recovery time of ecosystem.





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