Drivers of ecological drought recovery: Insights from meteorological and soil drought impact

Prolonged droughts typically have more severe impacts on ecosystems. The recovery time (RT) from drought is a crucial indicator for assessing the extent of drought impact on ecosystems. However, the drought recovery extent and dominant factors in the recovery characteristics of ecological drought (ED) from meteorological drought (MD) and soil drought (SD) remain to be further clarified. Therefore, this study employs reanalysis data and remote sensing vegetation indices to analyze the spatial patterns of ED recovery times from MD/SD (MRT/SRT). The dominant factors affecting RT across climatic zones were identified using random forest regression models and partial correlation, and the response characteristics of RT to these dominant factors under different land cover and irrigation types were explored. Regions with high recovery pressure and differential rates were identified, and their driving factors were explored. The results show that the SRT in China is approximately twice the MRT. Farmland experiences the highest MRT (4.9 months), particularly in the continuous and double-cropping irrigation areas of North China, while bare ground has the highest average SRT (6.4 months). MRT/SRT in China is most significantly influenced by surface temperature (TEM) and atmospheric vapor pressure deficit (VPD) during the recovery period, showing a predominant positive response to dominant factors across climatic zones. Grassland RT is notably affected by variations in all types of climatic factors. However, an increase in TEM and VPD significantly extends the RT of farmlands, especially in the double-cropping irrigation areas of North and Central China. Compared to MD, ED has more difficulty recovering from SD, exhibiting higher RT, recovery stress, and recovery differential rate. Decrease in soil moisture (SM) lead to poorer drought recovery outcomes. This study uncovers the differentiated recovery characteristics of ED in response to various types of drought and their dominant factors, deepening our understanding of the recovery process among different types of drought.