Vegetation Growth Response and Trends after Water Deficit Exposure in the Loess Plateau, China

Abstract

Understanding the impact of water availability on vegetation growth in the context of climate change is crucial for assessing the resilience of vegetation to environmental shifts. In this study, the relationship between vegetation growth and water availability was studied using a variety of indicators. The Normalized Difference Vegetation Index (NDVI), the Enhanced Vegetation Index (EVI), and Solar-Induced Chlorophyll Fluorescence (SIF) were utilized as vegetation growth indicators, while the standardized precipitation evapotranspiration index (SPEI) and soil moisture indicators served as water use indices. To investigate the vegetation response to water deficit in the Loess Plateau during the growing season from 2000 to 2020, Spearman’s rank correlation coefficients were calculated using a 5-year sliding window approach. The spatial and temporal heterogeneity of vegetation response to water deficit during the growing seasons were also explored. The results showed that: (1) with the improvement of moisture conditions, vegetation growth recovered significantly, and there was no expansion trend for vegetation water deficit. (2) The most sensitive timescale of vegetation to water deficit was 6–8 months; the response degree and sensitivity of vegetation to water surplus and deficit were the highest from June to August; and broadleaved forest was the vegetation type most sensitive to water deficit in the early growing season, while grass was the vegetation type most sensitive to water deficit during the mid and late growing seasons. (3) Soil moisture emerged as the dominant factor influencing vegetation growth in the Loess Plateau, followed by precipitation, albeit to a lesser extent. These findings contribute to understanding the mechanism and characteristics of the response of vegetation to climate fluctuations induced by global climate change.

Assessment of Spatiotemporal Patterns and the Effect of the Relationship between Meteorological Drought and Vegetation Dynamics in the Yangtze River Basin Based on Remotely Sensed Data

“…Compared to Pearson correlation, this method is less sensitive to outliers. Additionally, it does not depend on the distribution of variables and applies to various types of data, making it suitable for a wider range of applications [20,52,53]. We calculated the correlation coefficients and tested their significance (p < 0.05) using the following equation:…”

Increased sensitivity of vegetation to soil moisture and its key mechanisms in the Loess Plateau, China

“…These alterations, combined with human activities and agricultural practices, influence SM variation, subsequently changing the sensitivity of vegetation to SM. The increased air temperature could also exacerbate regional plant die-off and elevate background mortality rates, with temperature-sensitive carbon starvation in response to a period of protracted water stress(Adams et al, 2009), like prolonged water stress during typical summer seasons in the LP(Luo et al, 2023), thus enhances the sensitivity of vegetation to SM. The GGP, which converts cropland into forests or grassland, has successfully restored degraded lands and reduced soil erosion.…”