Divergent impacts of droughts on vegetation phenology and productivity in the Yungui Plateau, southwest China
Divergent impacts of droughts on vegetation phenology and productivity in the Yungui Plateau, southwest China
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DOI：
10.1016/j.ecolind.2021.107743
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发表时间：
2021-04-27
影响因子：
6.9
通讯作者：
Wang, Fei
中科院分区：
文献类型：
--
作者：
Ge, Wenyan;Han, Jianqiao;Wang, Fei
气候变化导致极端天气事件的严重程度和频率增加，特别是干旱。量化干旱对植被活动的影响对于研究气候变化对生态系统的影响至关重要。利用多时间尺度的总初级生产力(GPP)、物候学指标和标准化降水蒸发指数(SPEI)，评价了2001-2017年间云贵高原植被活动对干旱的差异响应。此外，利用植被活动与SPI的最大相关系数分析了高原植被对干旱的敏感性。结果表明，在研究期间，高原生长季的开始(SOS)和结束(EOS)总体变化不明显。与此同时，研究期间发生的两次极端干旱导致全球生产总值大幅下降，并导致SOS和EOS严重延误。东部高原由于植被抗旱性强，植被活动明显增加。相反，由于植被抗旱性较弱，西部地区植被活动动态，特别是物候指标的动态变化不明显。季前干旱的春季物候在决定SOS动态中起着关键作用。此外，夏前干旱是造成EOS延迟的主要原因，而夏季干旱是导致EOS提前的主要原因。因此，由于SOS和EOS之间的强烈相互作用，秋季季节前干旱对EOS的影响是非线性的。更重要的是，与EOS相比，SOS对年GPP的影响更大，这表明SOS的季前干旱对高原植被生产力是必不可少的。鉴于气候的持续变暖将导致更频繁的干旱，在未来的工作中调查植被生长对干旱的韧性至关重要。
Climate change has led to an increase in the severity and frequency of extreme weather events, especially droughts. Quantifying the impacts of droughts on vegetation activities is essential to study the effects of climate change on the ecosystem. Using Gross Primary Productivity (GPP), phenological metrics, and Standardized precipitation evaporation index (SPEI) with multi-timescales, we evaluated the divergent responses of vegetation activities to droughts in the Yungui Plateau from 2001 to 2017. Besides, the sensitivity of vegetation to drought was analyzed by the maximum correlation coefficients between vegetation activities and SPEI over the plateau. Results revealed that the overall changes of the start (SOS) and end (EOS) of growing season in the plateau exhibited nonsignificant changes during the study period. Meanwhile, two extreme droughts of the study period caused a tremendous decrease in GPP and severe delays in SOS and EOS. Vegetation activities increased significantly in the eastern plateau because of the strong drought resistance of vegetation. Conversely, the dynamics of vegetation activities, especially phenological metrics, were nonsignificant in the west due to the weak drought resistance of vegetation. Preseason droughts of spring phenology played a key role in determining SOS dynamics. Besides, drought before summer contributed to the delay of EOS, while summer drought leads to early EOS. Hence, preseason droughts of autumn phenology nonlinearly impacted EOS due to strong interaction between SOS and EOS. More importantly, the stronger influences of SOS on annual GPP compared to EOS suggest that preseason droughts of SOS are essential to the vegetation productivity in the plateau. Given that the continuous warming of the climate will lead to more frequent droughts, it is essential to investigate the resilience of vegetation growth to drought in future work.