The response of vegetation dynamics to drought and its driving factors identification in Inner Mongolia of China

Abstract

Drought has exerted significant impacts on terrestrial ecosystems and reduction in vegetation biomass through its unfavorable effects on vegetation growth status, and directly causing the degradation and death of vegetation. Therefore, investigating the response mechanisms of various vegetation types to drought is of great importance for vegetation resource conservation and sustainable development. In this study, based on the Vegetation Health Index (VHI) and Standardized Precipitation Evapotranspiration Index (SPEI), the dynamic changes and response relationships were revealed between vegetation and drought in Inner Mongolia (IM) during 1982–2020. Additionally, the fluctuation patterns of vegetation during drought events were identified. The results demonstrated that: (1) the probability of seasonal change point occurrence in VHI was 62.73 % in April 2018, with a confidence interval ranging from March 2014 to May 2019; (2) the identified optimal copula model was the Gaussian-copula for the duration and severity of drought events in IM; (3) the maximum and minimum percentages of degraded vegetation in IM occurred in January (74.32 %) and October (53.86 %); and (4) the cumulative lag-time of vegetation response to drought varied among different sub-regions, with response times ranging from 4 to 5 months. This finding provide a new perspective for elucidating the impact of drought variations on vegetation dynamics, which have positive implications for vegetation protection and ecological environment management.