Gao et al. (2025) Land quality degradation exacerbates the impact of drought on vegetation in Northeast China

Identification

• Journal: Ecological Indicators
• Year: 2025
• Date: 2025-11-21
• Authors: Shuhui Gao, Shengzhi Huang, Hui Guo, Haokui Yan, Lin Zhang, Yifei Li, Wei Guo, Xueying Zhu, Hongbo Ling, Wanghai Tao, Guoyong Leng, Qiang Huang
• DOI: 10.1016/j.ecolind.2025.114447

Research Groups

• State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi’an University of Technology, Xi’an, China
• School of Water Conservancy, North China University of Water Resources and Electric Power, Zhengzhou, China
• Ocean University of China College of Environmental Science and Engineering, Qingdao, China
• State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
• Northwest Engineering Corporation Limited, Xi’an, China
• Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China

Short Summary

This study quantifies the coupled effects of drought and land degradation on the vulnerability, resistance, and recovery of forest, crop, and grassland vegetation in Northeast China from 2001 to 2020, revealing that land degradation significantly amplifies drought impacts, increasing vulnerability and reducing resistance, particularly for forests under severe combined stress.

Objective

• To determine the vulnerability of vegetation in Northeast China under drought and land degradation conditions.
• To differentiate the resistance and recovery of vegetation under various stresses.
• To explore the impacts of different stresses on various vegetation types.

Study Configuration

• Spatial Scale: Northeast China (Liaoning, Jilin, Heilongjiang, and eastern Inner Mongolia). All datasets were resampled to a grid resolution of 0.25° × 0.25°.
• Temporal Scale: 2001 to 2020.

Methodology and Data

• Models used:
  • Standardized Precipitation Evapotapotranspiration Index (SPEI) for drought characterization.
  • Land Quality Index (LQI) derived from Normalized Relative Humidity Index (NMI), Soil Erosion Index (SEI), Greenness Index (GI), and Carbon Exchange Index (CEI), weighted by Principal Component Analysis (PCA).
  • Vine copula framework (C-Vine structure) to model the joint probability of drought, land degradation, and vegetation productivity.
  • Method by Isbell et al. (2015) to quantify vegetation resistance and recovery.
  • Structural Equation Modeling (SEM) to examine indirect pathways and causal relationships among variables.
• Data sources:
  • Meteorological data: ERA5-land reanalysis dataset (2 m dewpoint temperature, 2 m temperature, 10 m u/v wind components, surface net solar radiation, surface net thermal radiation, surface pressure, total precipitation) at hourly temporal resolution and 0.1° × 0.1° spatial resolution.
  • Soil physicochemical properties: Harmonized World Soil Database (HWSD) v1.2 (organic carbon, calcium carbonate content, soil texture) at 250 m spatial resolution.
  • Elevation data: GEBCO 2023 Grid.
  • Vegetation greenness/productivity:
    • Normalized Difference Vegetation Index (NDVI) from MOD13A2.061.
    • Land use from MCD12Q1.006.
    • Net Primary Production (NPP) from MOD17A3HGF.061.
    • Solar-Induced Chlorophyll Fluorescence (SIF) from GOSIF product (Li and Xiao, 2019) at 8-day temporal resolution and 0.05° spatial resolution.

Main Results

• Land degradation markedly amplifies drought impacts, increasing vegetation vulnerability and reducing resistance across Northeast China. The probability of vegetation loss is systematically higher under coupled drought and land degradation than under drought alone.
• Under coupled stresses, vegetation resistance is relatively strong in the north, while recovery is generally low (<0.3), with lowest values in the northeast, south, and west. Mean resistance decreased by 0.061 and median resistance by 0.074 when land degradation was added to drought conditions, with recovery largely unchanged.
• Vegetation type responses:
  • Under drought alone, vegetation loss probability generally followed: grassland > crop > forest. Forests showed the highest resistance but were most dependent on land quality.
  • Under coupled drought and land degradation, forests became the most vulnerable under moderate and severe drought with increasing land quality decline (forest > crop > grassland).
  • A trade-off between resistance and recovery was observed across ecosystems, with forests exhibiting the highest resistance but lowest recovery, followed by crops, then grasslands (highest recovery).
  • When land degradation was added to drought, forest resistance and recovery declined; grassland resistance decreased, but recovery increased; crop resistance declined with no significant change in recovery.
• Structural Equation Modeling revealed that degradation-exacerbated-drought zones exhibited poorer soil physicochemical properties, weaker positive effects of organic carbon on soil moisture, and reduced soil available water capacity (SAWC), leading to lower vegetation transpiration despite higher precipitation and soil moisture compared to non-exacerbated zones.

Contributions

• Provides a comprehensive regional assessment quantifying the vulnerability, resistance, and recovery of major vegetation types under coupled drought and land degradation in Northeast China.
• Offers mechanistic insights into vegetation dynamics under dual stressors, highlighting the critical role of land quality feedbacks.
• Emphasizes the necessity of incorporating land quality into vegetation models for improved predictive capabilities under climate change.
• Delivers a scientific foundation for developing targeted ecological restoration strategies and enhancing regional ecosystem services in ecologically vulnerable regions.

Funding

• Strategic Priority Research Program of the Chinese Academy of Sciences (grant number XDA28060100)
• National Natural Science Foundation of China (grant number 52279026)

Citation

@article{Gao2025Land,
  author = {Gao, Shuhui and Huang, Shengzhi and Guo, Hui and Yan, Haokui and Zhang, Lin and Li, Yifei and Guo, Wei and Zhu, Xueying and Ling, Hongbo and Ma, Ling and Tao, Wanghai and Leng, Guoyong and Huang, Qiang},
  title = {Land quality degradation exacerbates the impact of drought on vegetation in Northeast China},
  journal = {Ecological Indicators},
  year = {2025},
  doi = {10.1016/j.ecolind.2025.114447},
  url = {https://doi.org/10.1016/j.ecolind.2025.114447}
}