干旱对锡林郭勒草原植被净初级生产力的影响

Effects of Drought on Net Primary Productivity of Vegetation in the Xilingol Grassland

为了探讨干旱对锡林郭勒草原植被净初级生产力(Net Primary Productivity,NPP)的影响,本文基于2000~2020年12个月尺度的标准化降水蒸散指数(Standardized Precipitation Evapotranspiration Index,SPEI)和同一时期的MODIS(Moderate-resolution Imaging Spectroradiometer)NPP数据,运用Theil-Sen趋势分析和Mann-Kendall非参数检验方法对干旱与NPP时空变化特征进行分析,并采用相关分析方法探讨干旱对锡林郭勒草原NPP的影响。结果表明:锡林郭勒草原气候整体呈湿润趋势,东部较西部更为明显;NPP呈增加趋势,由东北向西南递减;SPEI与NPP呈正相关的面积达99.88%,说明植被状况随着干旱的缓解整体趋于好转;时间上,SPEI与不同植被类型NPP均呈显著正相关,其中相关性最大的是典型草原;干旱的发生会造成NPP损失,其减少幅度随干旱强度和面积的增加而上升。研究结果可为应对气候变化、抗灾减灾等工作提供科学依据。

To investigate the effects of drought on NPP(Net Primary Productivity)in the Xilingol grassland,this paper used the 12-month SPEI(Standardized Precipitation Evapotranspiration Index)and MODIS MOD17A3 NPP data from 2000 to 2020.The temporal and spatial variation characteristics of drought and NPP were analyzed based on the Theil–Sen trend analysis and Mann–Kendall nonparametric test,and the correlation analysis method was used to assess the impact of drought on NPP in the Xilingol grassland.The results showed that the climate of the Xilingol grassland is humid,particularly in its eastern part.NPP showed an increasing trend and a decreasing trend from northeast to southwest.In space,SPEI is mainly positively correlated with NPP,with an area of 99.88%,indicating that vegetation conditions tended to improve with drought relief.Temporally,SPEI was significantly positively correlated with NPP in all vegetation types,with the strongest correlation observed in typical steppe.Drought occurrence will cause NPP loss,which will increase with increasing drought intensity and area.These research results can provide a scientific basis for investigating climate change,disaster relief,and other issues.