Drought timing and climate conditions determine the vegetation recovery

Abstract:

Drought, with major impacts on both human and natural systems, is the most widespread climatic extreme that negatively affects the land carbon sink. Recovery time—how long an ecosystem requires to revert to its pre-drought functional state—is a critical metric of drought impact. Yet the factors (e.g., drought characteristics and climatic conditions) that interact to affect drought recovery at the global scale remain unknown. Here, we used remote sensing retrievals of Normalized Difference Vegetation Index (NDVI) and multiple climate factors during 1992-2015. The results showed that across diverse ecosystems, drought recovery times are strongly associated with drought timing, long term climatic water balance (P-PET) than soil. Drought-induced reductions in vegetation growth were greatest when the droughts occurred during the early-growing season; thus it took longer for them to recover, especially for vegetation in the warmest, driest regions (i.e., highest P-PET). Further, post-recovery climatic variables (e.g., temperature or snow water equivalence) and their interaction with drought timing were important predictors of drought recovery.