Traditional lake ecological risk assessments often focus on a single perspective—such as water quality or landscape pattern—while overlooking the critical linkages between aquatic and terrestrial ecosystems within lake basins. In a new study published in Water & Ecology , a research team led by Bo Jiang from Changjiang Water Resource Protection Institute developed a novel "Hydrology–Environment–Ecology" framework that integrates aquatic ecological risk (AER) assessment with landscape ecological risk (LER) evaluation across basin boundaries.
The proposed framework integrates four key components:
1) a "Hydrology–Environment–Ecology" framework for AER assessment incorporating water level, pollution (TN and TP), and habitat quality;
2) landscape pattern metrics for LER assessment based on land-use data;
3) concentric buffer zone analysis to explore the correlation between AER and LER across distances; and
4) interpretable machine learning (XGBoost–SHAP) combined with partial least squares structural equation modeling (PLS-SEM) to reveal the effects and mechanisms of socio-ecological factors on ecological risk.
“Applied to Chaohu Lake, the framework reveals significant increasing trends in both aquatic and terrestrial ecological risks from 2000 to 2019,” shares Jiang. “The AER in Chaohu Lake rose from 0.32 to 0.61, with habitat quality identified as the key risk indicator (weight = 0.39).”
Meanwhile, the mean LER in the basin increased from 0.0193 to 0.0214, and the area of high-risk regions expanded by 384.97%, with risk hotspots concentrated around urban centers such as Hefei, Chaohu, and Wuwei.
“Recognizing and addressing the spatial heterogeneity of ecological risk is crucial for enhancing the effectiveness of lake conservation,” explains first author Jiacheng Huang. “The spatial bipolarization we observed—where both high-risk and low-risk areas expanded concurrently—indicates that uniform management strategies would be inadequate.”
The analysis revealed a strong positive correlation between AER and LER dynamics, with correlation coefficients ranging from 0.88 to 0.75 as buffer width increased. “We identified an 8-km riparian buffer zone as a critical threshold where the correlation between landscape and aquatic risk shifts markedly. This distance corresponds closely to the basin's distinct topographic gradient and disproportionately high anthropogenic pressure, making it the optimal target for integrated conservation interventions,” says Huang.
To uncover the mechanisms driving ecological risk, the team employed XGBoost–SHAP and PLS-SEM.
“Nighttime light was identified as the dominant factor influencing LER throughout the entire period, with SHAP values increasing steadily from 0.0017 to 0.0044,” says Huang. “The impact of impervious surface percentage increased rapidly, with its SHAP value rising from 0.0003 to 0.0013, making it the second most influential factor by 2019.”
Structural equation modeling further revealed that human activity dominated the enhancement of LER through both direct (0.359) and indirect effects (0.372), surpassing the constraints imposed by terrain conditions.
“These findings demonstrate that human activity, particularly socioeconomic intensity reflected by nighttime light and urban expansion, is the dominant driver of ecological risk,” adds Huang. “While enhancing vegetation cover can provide mitigation—our analysis identified an effectiveness threshold at an NDVI of 0.45—it is insufficient to fully offset the overarching negative impacts of human activities.”
Based on the quantitative insights from the integrated risk assessment, the researchers proposed cross-scale management implications. “At the basin scale, controlling impervious surface expansion and establishing ecological corridors are critical to improve landscape connectivity,” says Jaing. “At the lakeshore conservation area scale, restricting human activities—including industrial production, pollution discharge, and large-scale livestock breeding—and promoting intensive, efficient agriculture are essential.”
At the lake scale, the researchers proposed integrated governance based on the “Hydrology–Environment–Ecology” perspective is imperative, combining exogenous pollution control with endogenous pollution management and habitat restoration.
“Ultimately, the framework supports linking aquatic ecological risk assessment with terrestrial landscape management and institutionalizes these approaches through integrated basin governance,” Jiang says. “The integrated assessment framework and workflow developed in this study provide a transferable paradigm for aquatic–terrestrial ecological risk integration, with high applicability to lakes in the lower Yangtze River region and adaptation potential for other multistressed lake ecosystems worldwide.”
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Contact the author:
Bo Jiang
Changjiang Water Resource Protection Institute, Wuhan 430051, China
Key Laboratory of Ecological Regulation of Non-Point Source Pollution in Lake and Reservoir Water Sources, Changjiang Water Resources Commission, Wuhan 430051, China
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Water & Ecology
Computational simulation/modeling
Not applicable
Integrated Framework for Lake Ecological Risk Assessment: Prioritizing Areas and Uncovering Mechanisms across Aquatic–Terrestrial Boundaries
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.