Response Modes of Global Vegetation to Extreme Drought

Abstract

Increasingly frequent extreme droughts pose a serious threat to global vegetation. However, previous studies have not characterized the whole response process of vegetation to drought, and there are uncertainties in their methods and indicators. In this study, we developed a new indicator system and derived the response modes of global vegetation to extreme drought. We examined the influence of environmental variables on the modes, as well as the temporal changes of vegetation's responses. We found that vegetation in low- and mid-latitude regions exhibited contrasting response modes to extreme drought. Long-term moisture played a dominant role in shaping the spatial patterns. Over the past 40 years, both the total loss and response time of global vegetation have increased with time. Among various biome types, tropical and subtropical moist broadleaf forests exhibited a mode of low maximum decrease and short response time to extreme drought, resulting in the lowest total loss, whereas temperate grasslands, savannas and shrublands demonstrated high vulnerability in both current and future trends, warranting great attention. These results provide valuable insights for a more comprehensive understanding of global vegetation's responses to extreme drought and for assessing the vulnerability of different biome types.