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| Relationship between landscape patterns and non-point source pollution processes in the Zijiang catchment tail, China |
| Received:September 22, 2020 |
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| KeyWord:non-point source pollution;landscape pattern;SWAT model;redundancy analysis;Zijiang catchment tail |
| Author Name | Affiliation | E-mail | | JIA Yu-xue | College of Geographic Science, Hunan Normal University, Changsha 410081, China
Key Laboratory of Geospatial Big Data Mining and Application, Hunan Normal University, Changsha 410081, China | | | SHUAI Hong | College of Geographic Science, Hunan Normal University, Changsha 410081, China
Key Laboratory of Geospatial Big Data Mining and Application, Hunan Normal University, Changsha 410081, China | 56331353@qq.com | | HAN Long-fei | College of Geographic Science, Hunan Normal University, Changsha 410081, China | |
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| Abstract: |
| In order to identify the critical source areas of non-point source(NPS) pollution and explore the relationship between the NPS pollution process and landscape patterns in the Zijiang catchment tail, the SWAT model was applied to simulate the spatiotemporal output characteristics of NPS pollution for total nitrogen and total phosphorus. The landscape pattern metric was utilized to quantitatively assess the characteristics of the landscape pattern. The relationship between NPS pollution and the landscape pattern was analyzed by the redundancy analysis(RDA) method from the two levels of landscape and patch type at the sub-basin scale. The R2 and ENS values of runoff, total nitrogen, and total phosphorus were all greater than 0.66 in the periods of calibration and verification, thereby indicating that the SWAT model has good applicability in the study area. The spatial distribution of the critical source areas of total nitrogen and total phosphorus was not completely consistent. In the critical period of NPS pollution, the critical source areas contributed 31.64% and 43.73% of the total NPS pollution in the study area, respectively. The landscape pattern was significantly correlated with the NPS pollution process. At the landscape level, the RDA between the landscape metric and pollution load showed that the more fragmented the landscape, the more complex the landscape type, and the greater the impact of human activities on the landscape, the higher the output value of the NPS pollution load. At the type level, the aggregation index, largest patch index, average patch area, and patch edge density were the common indicators that had a significant influence on the source and sink landscapes; the larger the fragmentation degree, the larger the patch area, and the higher the aggregation degree, the stronger the output of the NPS pollution load. Meanwhile, the sink landscape with small fragmentation, a complex landscape shape, and high patch connectivity could help to intercept NPS pollution. The study shows that there is a clear internal relationship between the process of NPS pollution and the landscape pattern of sources and sinks, and the rational layout of the landscape of sources and sinks can reduce the risk of NPS pollution. This study provides a reference for the prevention and control of NPS pollution from the perspective of land use. |
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