Rahman et al. (2026) Comprehending the impact of hydro-meteorological droughts on ecosystem vulnerability and resilience across the Indus River Basin in Pakistan

Identification

• Journal: Journal of Environmental Management
• Year: 2026
• Date: 2026-03-01
• Authors: Khalil Ur Rahman, Shahanshah Abbas, Aftab Haider Khan, Songhao Shang, Anwar Hussain, Deqiang Mao
• DOI: 10.1016/j.jenvman.2026.129077

Research Groups

• School of Civil Engineering, Shandong University, Jinan, Shandong, China
• Department of Hydraulic Engineering, Tsinghua University, Beijing, China
• Department of Economics and Development Studies, University of Swat, Swat, Pakistan

Short Summary

This study develops a catchment-based integrated drought index (CIDI) for the Indus River Basin by integrating the Standardized Precipitation Evapotranspiration Index (SPEI) and the Standardized Water Availability Index (SWAI), and assesses ecosystem vulnerability and resilience, finding CIDI to be robust and identifying extreme vulnerability in the Middle and Lower Indus Basins.

Objective

• To develop a catchment-based integrated drought index (CIDI) by systematically integrating the Standardized Precipitation Evapotranspiration Index (SPEI) and the Standardized Water Availability Index (SWAI) across the Indus River Basin of Pakistan.
• To comprehensively evaluate CIDI, SPEI-IADI, and SWAI-IADI across 27 catchments within the Indus River Basin.
• To assess ecosystem vulnerability and resilience to drought using the Remote Sensing-based Ecological Index.

Study Configuration

• Spatial Scale: Indus River Basin, Pakistan, across 27 catchments, at a resolution of 0.25° × 0.25°.
• Temporal Scale: 1990–2023.

Methodology and Data

• Models used: Catchment-based Integrated Drought Index (CIDI), Standardized Precipitation Evapotranspiration Index (SPEI), Standardized Water Availability Index (SWAI), Integrated Agricultural Drought Indices based on SPEI (SPEI-IADI), Integrated Agricultural Drought Indices based on SWAI (SWAI-IADI), Bayesian Vector Auto-Regressive, Bayesian Principal Component Analysis (BPCA), Bayesian Model Averaging, Remote Sensing-based Ecological Index (RSEI), Standardized Soil Moisture Index (SSMI), Vegetation Condition Index (VCI), Temperature Condition Index (TCI), Vegetation Health Index (VHIa).
• Data sources: Remote sensing (for RSEI and related indices), and underlying meteorological and hydrological data for SPEI and SWAI calculation.

Main Results

• Insignificant causal relationships were found for SPEI with Standardized Soil Moisture Index (SSMI) and Vegetation Condition Index (VCI) in the Upper Indus Basin (UIB); Temperature Condition Index (TCI), SSMI, and arithmetic mean-based Vegetation Health Index (VHIa) in the Middle Indus Basin (MIB); and SSMI in the Lower Indus Basin (LIB).
• SWAI depicted insignificant causal relationships with SSMI, TCI, and VHIa across UIB.
• The relationship between SWAI and SSMI across MIB and LIB is relatively more dominant compared to that with SPEI.
• Bayesian Principal Component Analysis (BPCA) highlighted the significant role of temperature in the onset, spatiotemporal propagation, and transition of droughts.
• Some pixels in MIB showed significant variations in BPCA weights, dominated by both temperature- and vegetation-derived indices.
• Bayesian Model Averaging assigned minimal weights to SWAI-IADI, likely due to its shorter duration and propagation time.
• CIDI proved to be a more robust index, outperforming both SPEI-IADI and SWAI-IADI.
• Ecosystems were found to be extremely vulnerable in LIB and MIB both spatially and temporally.
• High ecosystem resilience was observed in UIB, attributed to its favorable cryosphere and climate.

Contributions

• Development of a novel catchment-based integrated drought index (CIDI) by systematically integrating SPEI and SWAI using Bayesian statistical methods.
• Comprehensive evaluation of drought indices and ecosystem vulnerability/resilience across the Indus River Basin.
• Highlighting the importance of integrating ecosystem vulnerability and considering contributions from meteorological and hydrological droughts when developing integrated indices.
• Providing region-specific insights into drought impacts and ecosystem responses across different sub-basins of the Indus River Basin.

Funding

• [No specific funding information provided in the paper text.]

Citation

@article{Rahman2026Comprehending,
  author = {Rahman, Khalil Ur and Abbas, Shahanshah and Khan, Aftab Haider and Shang, Songhao and Hussain, Anwar and Mao, Deqiang},
  title = {Comprehending the impact of hydro-meteorological droughts on ecosystem vulnerability and resilience across the Indus River Basin in Pakistan},
  journal = {Journal of Environmental Management},
  year = {2026},
  doi = {10.1016/j.jenvman.2026.129077},
  url = {https://doi.org/10.1016/j.jenvman.2026.129077}
}