Impacts of drought and heat events on vegetative growth in a typical humid zone of the middle and lower reaches of the Yangtze River, China

Due to climate change, the frequencies of extreme meteorological events have increased around the world over the last few decades, which would significantly affect the growth of vegetation, especially in humid regions. However, few previous studies have investigated the effects of compound extreme meteorological events on the growth of vegetation, such as compound drought and heat events (CDHEs). In this research, we assessed the individual and interactive impacts of drought and heat events on the growth of vegetation using geographic detectors in the Poyang Lake Basin (PYLB), which is located in a typical humid zone in the middle and lower reaches of the Yangtze River (MLYR) of China. We found that the effect of heat events on the growth of vegetation was greater than that of drought events in this region. Among the various vegetation types, shrubland (SL) and cultivated vegetation (CV) were most significantly affected by drought and heat events, respectively, and broadleaf forest (BLF) was more tolerant of drought (heat) events than other vegetation. Drought events had significantly negative effects on the growth of vegetation, and needle-leaf (NLF) and BLF exhibited a two-month lagged response. The impact of CDHE on the growth of vegetation was remarkably stronger than that of a single event, and the interaction type was bi-factor enhanced or nonlinear enhanced. Our findings highlight the need to consider CDHEs when assessing the response of vegetation to climate extremes under global warming.