Changes in Vegetation Resistance and Resilience under Different Drought Disturbances Based on NDVI and SPEI Time Series Data in Jilin Province, China

Abstract

Extreme drought is increasing in frequency and intensity in many regions globally. Understanding the changes in vegetation resistance and resilience under aggravated drought is essential for maintaining regional ecosystem stability. In this study, a drought event–vegetation response framework was developed to explore vegetation resistance and resilience changes. The normalized difference vegetation index (NDVI) was correlated with the standardized precipitation evapotranspiration index (SPEI) at multiple timescales to screen out the vegetation response time to drought. Then, the SPEI for the response time was detected using run theory to identify drought events during the period 2000–2017. Finally, drought-induced NDVI anomaly changes were identified using a sliding window to explore the changes in resistance and resilience to drought. This study focuses on Jilin province, China, which contains a famous environmentally vulnerable area. The results illustrate that the response time of vegetation to drought is 3 months. The northwest of Jilin province is considered to be drought-vulnerable because it has suffered the most drought events, i.e., 19–21 times, with severities in the range of 2.6–3.2 and durations in the range of 3.6–4.1 months. Grassland shows the weakest resistance and the strongest resilience, and tree cover shows the strongest resistance and the weakest resilience under severe drought disturbance among all vegetation. As the severity and duration of drought increase, the resistance decreases, and the resilience increases. During the growing season, the drought from May to July significantly impacts the vegetation resistance. Drought occurring from June to July has much less impact on resilience. Drought in August to September has less impact on resistance and a more significant impact on resilience. The results of this study may increase our knowledge regarding the response of vegetation to drought and guide ecosystem stability restoration.

Temporal and Spatial Evolution of Meteorological Drought in Inner Mongolia Inland River Basin and Its Driving Factors

“…However, identifying drought events and extracting drought characteristic variables from historical drought time series is the prerequisite for analyzing the spatio-temporal evolution characteristics and development laws of drought. Ma et al calculated the SPEI and Normalized Difference Vegetation Index (NDVI) at different scales in Jilin Province from 2000 to 2017, and used the run theory to detect the SPEI of the optimal response time of vegetation drought, and analyzed the drought events in the study area [26]. Du et al calculated the Meteorological Drought Composite Index (MCI) based on the meteorological stations data in the Beijing-Tianjin-Hebei region of China from 1961 to 2023, and analyzed the variation characteristics of drought in this region based on the MCI [27].…”