Yang et al. (2025) Assessment of monthly vegetation response and ecosystem risks to drought-flood abrupt alternation using an integrated framework

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-11-09
• Authors: Boyuan Yang, Keke Zhou, Ping Feng, Xuejun Yang
• DOI: 10.1016/j.jhydrol.2025.134572

Research Groups

• State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation, Tianjin University, Tianjin, China
• Haihe River Water Conservancy Commission of Ministry of Water Resources, Tianjin, China

Short Summary

This study investigates the distinct monthly vegetation response and ecosystem risks to drought-flood abrupt alternation (DFAA) modes (drought-to-flood and flood-to-drought) in the Hai River Basin, revealing a novel seasonal reversal in vegetation vulnerability and ecosystem risk patterns.

Objective

• To understand the distinct response characteristics of vegetation to drought to flood (DTF) and flood to drought (FTD) stress occurring across different months within the context of seasonal differences, and to assess ecosystem risks in the Hai River Basin.

Study Configuration

• Spatial Scale: Hai River Basin (HRB)
• Temporal Scale: Monthly scale, seasonal analysis.

Methodology and Data

• Models used: Improved drought-flood abrupt alteration index (DFAI) based on the standardized precipitation evapotranspiration index (SPEI), trivariate conditional probability model, extreme weather risk framework (integrating hazard, vulnerability, and exposure), Vine copula.
• Data sources: Not explicitly detailed, but likely includes hydro-meteorological data for SPEI calculation and remote sensing data for vegetation indices (e.g., Normalized Difference Vegetation Index - NDVI).

Main Results

• The frequency and intensity of drought-to-flood (DTF) events exhibited nonsignificant increasing trends of 0.005 per decade and 0.003 per decade, respectively, while flood-to-drought (FTD) events showed nonsignificant declining trends.
• Drought-flood abrupt alternation (DFAA) events were more likely to occur in summer and autumn.
• Vegetation vulnerability to DTF and FTD is seasonally dependent: from April to July, FTD induced significantly higher vegetation loss probability (VLP) than DTF, with the most pronounced disparity in spring. In contrast, DTF exerted greater impacts during late summer and autumn.
• The spatial heterogeneity of VLP differences caused by FTD and DTF was primarily driven by the Normalized Difference Vegetation Index (NDVI).
• Ecosystem risk patterns for DTF and FTD were distinct seasonally and spatially. In spring, the areal coverage of middle-high and high-risk zones triggered by FTD (15.9%) was substantially higher than that of DTF (0.7%), while the opposite pattern occurred in summer and autumn.
• Risk levels in mountainous areas were generally higher than in plains.

Contributions

• Proposed an improved drought-flood abrupt alteration index (DFAI) that demonstrably outperforms the original in identifying short-cycle DFAA events and quantifying their true intensity.
• Reported for the first time at a regional scale, a seasonal reversal in vegetation vulnerability to drought-to-flood (DTF) and flood-to-drought (FTD) events.
• Offers critical insights for developing seasonally targeted agricultural risk management strategies.
• Applied an integrated extreme weather risk framework to evaluate ecosystem risks to DFAA.

Funding

• Not explicitly detailed in the provided text.

Citation

@article{Yang2025Assessment,
  author = {Yang, Boyuan and Zhou, Keke and Li, Jianzhu and Feng, Ping and Yang, Xuejun},
  title = {Assessment of monthly vegetation response and ecosystem risks to drought-flood abrupt alternation using an integrated framework},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2025.134572},
  url = {https://doi.org/10.1016/j.jhydrol.2025.134572}
}