Contrasting responses of woody and grassland ecosystems to increased CO2 as water supply varies
Contrasting responses of woody and grassland ecosystems to increased CO2 as water supply varies
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DOI：
10.1038/s41559-021-01642-6
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发表时间：
2022-01
影响因子：
16.8
通讯作者：
Yude Pan;R. B. Jackson;D. Hollinger;O. Phillips;R. Nowak;R. Norby;R. Oren;P. Reich;A. Lüscher;Kevin Mueller;J. Nösberger;C. Owensby;R. Birdsey;J. Hom;Yiqi Luo
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作者：
Yude Pan;R. B. Jackson;D. Hollinger;O. Phillips;R. Nowak;R. Norby;R. Oren;P. Reich;A. Lüscher;Kevin Mueller;J. Nösberger;C. Owensby;R. Birdsey;J. Hom;Yiqi Luo
实验表明，大气中二氧化碳（eCO2）升高通常会增强植物的光合作用和生产力，但这种效果变化很大，并且可能对气候敏感。了解供水是否、在何处以及如何调节二氧化碳的增加对于预测陆地对大气二氧化碳增加和气候变化的反应至关重要。在这里，我们利用 14 个长期生态系统规模的 CO2 实验的数据表明，年地上净初级生产力的 eCO2 增强对年降水量敏感，并且这种敏感性在木本和草原生态系统之间有所不同。在潮湿的年份，木本生态系统的二氧化碳增加量增加，但以草为主的系统减少。与这种差异相一致，在 eCO2 作用下，木本生态系统可以比草地生态系统更有效地增加湿润年份的叶面积指数。总体而言，在不同的降水情况下，木本系统的二氧化碳增加量 (24%) 明显强于草地 (13%)。我们建立了一种基于叶面积指数变化的经验关系来量化地上净初级生产力的提高，为评估eCO2对陆地生态系统生产力的影响提供了一种新方法。
Experiments show that elevated atmospheric CO2(eCO2) often enhances plant photosynthesis and productivity, yet this effect varies substantially and may be climate sensitive. Understanding if, where and how water supply regulates CO2enhancement is critical for projecting terrestrial responses to increasing atmospheric CO2and climate change. Here, using data from 14 long-term ecosystem-scale CO2experiments, we show that the eCO2enhancement of annual aboveground net primary productivity is sensitive to annual precipitation and that this sensitivity differs between woody and grassland ecosystems. During wetter years, CO2enhancement increases in woody ecosystems but declines in grass-dominated systems. Consistent with this difference, woody ecosystems can increase leaf area index in wetter years more effectively under eCO2than can grassland ecosystems. Overall, and across different precipitation regimes, woody systems had markedly stronger CO2enhancement (24%) than grasslands (13%). We developed an empirical relationship to quantify aboveground net primary productivity enhancement on the basis of changes in leaf area index, providing a new approach for evaluating eCO2impacts on the productivity of terrestrial ecosystems.