Impacts of Climate–Land Use Interactions and Topographic Thresholds on Nitrogen and Phosphorus Export Risks in Mountainous Watersheds: A Case Study in Yunnan, China.
4 affiliations
- 1Faculty of Geography, Yunnan Normal University, Kunming 650,500, China; Yunnan Normal University, The Engineering Research Center of GIS Technology in Western China, Ministry of Education, Kunming 650,500, China
- 2Faculty of Geography, Yunnan Normal University, Kunming 650,500, China; Yunnan Normal University, The Engineering Research Center of GIS Technology in Western China, Ministry of Education, Kunming 650,500, China; Corresponding authors at: Faculty of Geography, Yunnan Normal University, Kunming 650,500, China.
- 3Faculty of Geography, Yunnan Normal University, Kunming 650,500, China
- 4Faculty of Geography, Yunnan Normal University, Kunming 650,500, China; Yunnan International Joint Laboratory of Resource and Security in the Indian Ocean Region, China
Abstract
Elucidating the drivers and risk evolution of nitrogen (N) and phosphorus (P) export is fundamental to non-point source (NPS) pollution management. However, existing research focuses primarily on factor contributions or statistical thresholds, often failing to translate attribution results and thresholds into spatial risk diagnostics. This disconnect between mechanistic understanding and spatially targeted management constitutes a critical knowledge gap. This study addresses this knowledge gap by integrating InVEST-NDR modeling, counterfactual factor decomposition, XGBoost-SHAP interpretation, and segmented regression to quantify the relative contributions, nonlinear responses, and threshold relationships of N and P export drivers in Yunnan Province. An ESI-based spatial risk classification framework—integrating environmental sensitivity, source pressure, and climate–land use interaction increments—was developed to delineate priority management zones. The results indicate that: (1) Land use and land cover (LULC) change contributed most (57.2%) with strong temporal persistence; climate effect (33.5%) showed pronounced interannual variability. (2) Cropland area and precipitation exhibited continuously enhancing responses; distance from rivers (DFR) and elevation (DEM) displayed L-shaped threshold responses, with export sensitivity significantly increasing when DFR < 2.3 km and DEM < 1.9 km. (3) Significant synergistic associations exist between cropland change and environmental conditions; agricultural source pressure overlapping with near-river, low-elevation, and high-precipitation zones amplified N and P export risk. (4) Compound high-risk zones accounted for 6.4% in 2020, concentrated in river corridors and agricultural basins, representing priority areas for NPS control. Projected risk patterns diverge substantially across Shared Socioeconomic Pathways (SSPs), with high-emission scenarios posing considerably greater adaptive management challenges. This study quantifies the relative contributions of climate and LULC change to N and P export dynamics and identifies spatial risk patterns, providing evidence-based guidance for targeted NPS pollution management in mountainous watersheds under climate change.
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BibTeX
@article{zhu2026impacts,
title = {{Impacts of Climate–Land Use Interactions and Topographic Thresholds on Nitrogen and Phosphorus Export Risks in Mountainous Watersheds: A Case Study in Yunnan, China.}},
author = {Jiaying Zhu and Shuangyun Peng and Zhiqiang Lin and Juexian Dong and Ziyi Zhu and Xianchun Pan and Weihang Wang and Yezhou Xiang and Fapeng Cai},
journal = {Ecological Indicators},
year = {2026},
month = oct,
doi = {10.1016/j.ecolind.2026.115527},
url = {https://doi.org/10.1016/j.ecolind.2026.115527},
note = {CC BY},
}
RIS
TY - JOUR
TI - Impacts of Climate–Land Use Interactions and Topographic Thresholds on Nitrogen and Phosphorus Export Risks in Mountainous Watersheds: A Case Study in Yunnan, China.
AU - Jiaying Zhu
AU - Shuangyun Peng
AU - Zhiqiang Lin
AU - Juexian Dong
AU - Ziyi Zhu
AU - Xianchun Pan
AU - Weihang Wang
AU - Yezhou Xiang
AU - Fapeng Cai
PY - 2026
DA - 2026/10/23
JO - Ecological Indicators
DO - 10.1016/j.ecolind.2026.115527
UR - https://doi.org/10.1016/j.ecolind.2026.115527
AB - Elucidating the drivers and risk evolution of nitrogen (N) and phosphorus (P) export is fundamental to non-point source (NPS) pollution management. However, existing research focuses primarily on factor contributions or statistical thresholds, often failing to translate attribution results and thresholds into spatial risk diagnostics. This disconnect between mechanistic understanding and spatially targeted management constitutes a critical knowledge gap. This study addresses this knowledge gap by integrating InVEST-NDR modeling, counterfactual factor decomposition, XGBoost-SHAP interpretation, and segmented regression to quantify the relative contributions, nonlinear responses, and threshold relationships of N and P export drivers in Yunnan Province. An ESI-based spatial risk classification framework—integrating environmental sensitivity, source pressure, and climate–land use interaction increments—was developed to delineate priority management zones. The results indicate that: (1) Land use and land cover (LULC) change contributed most (57.2%) with strong temporal persistence; climate effect (33.5%) showed pronounced interannual variability. (2) Cropland area and precipitation exhibited continuously enhancing responses; distance from rivers (DFR) and elevation (DEM) displayed L-shaped threshold responses, with export sensitivity significantly increasing when DFR < 2.3 km and DEM < 1.9 km. (3) Significant synergistic associations exist between cropland change and environmental conditions; agricultural source pressure overlapping with near-river, low-elevation, and high-precipitation zones amplified N and P export risk. (4) Compound high-risk zones accounted for 6.4% in 2020, concentrated in river corridors and agricultural basins, representing priority areas for NPS control. Projected risk patterns diverge substantially across Shared Socioeconomic Pathways (SSPs), with high-emission scenarios posing considerably greater adaptive management challenges. This study quantifies the relative contributions of climate and LULC change to N and P export dynamics and identifies spatial risk patterns, providing evidence-based guidance for targeted NPS pollution management in mountainous watersheds under climate change.
SN - 1470-160X
SN - 1872-7034
ER -