Diverse spatiotemporal responses in vegetation growth to droughts in China.

Global warming-related climate changes have significantly impacted the growth of terrestrial vegetation. Quantifying the spatiotemporal characteristic of the vegetation’s response to climate is crucial for assessing the potential impacts of climate change on vegetation. This study analyzed the spatiotemporal responses of different vegetation types across China between the normalized difference vegetation index (NDVI) that reflects vegetation activity and the standardized precipitation evapotranspiration index (SPEI) that indicates drought conditions by reflecting water conditions at different timescales. The NDVI was separated into 12 time series (one per month), and the SPEI of 12 droughts timescales was used to make the correlation. The results suggest that the response of vegetation growth to changes in the SPEI varies according to vegetation type. Specifically, positive correlations are found in arid and sub-arid environments where soil water is a primary constraining factor for plant growth, while negative correlations exist in humid environments, corresponding to regions where soil water is commonly sufficient. The results also show that negative correlations occur primarily at short timescales (1–5 months) in spring and winter and positive correlations correspond to long timescales (9–12 months) in summer. Further spatial analysis indicates that positive correlations are primarily found in northern China which is a region that has a primarily negative water balance (i.e., water deficits) while negative correlations are primarily found in southern China. The disclosed patterns of spatiotemporal responses in vegetation growth to droughts are important for impact assessments of climate change on vegetation growth. [ABSTRACT FROM AUTHOR]