Faculty of Geography, Yunnan Normal University, Kunming, 650500, China.
GIS Technology Engineering Research Centre for West-China Resources and Environment of Education-Al Ministry, Kunming, 650500, China.
Environ Sci Pollut Res Int. 2022 Jun;29(29):44103-44118. doi: 10.1007/s11356-022-18970-0. Epub 2022 Feb 5.
It is of great significance to analyze the threshold relationship between landscape pattern and water quality for watershed water environment treatment. However, previous studies did not consider the influence of spatial scale on threshold. Therefore, this study proposed the idea of the relationship between landscape pattern and water quality threshold considering the spatial scale effect to solve the above problems. Firstly, the percentage of landscape composition area under 9 spatial scales (riparian buffer zone and sub-basin) of 20 rivers entering the lake in Dianchi Lake Basin was extracted to identify the optimal spatial scale of landscape pattern and water quality by redundant analysis (RDA). Then, a variety of nonlinear regression models such as power regression, exponential regression, quadratic regression, and segmented regression are used to quantitatively detect the thresholds of landscape pattern and water quality. The results show that (1) the spatial scale has a significant influence on the threshold relationship between landscape pattern and water quality, and the total interpretation rate of landscape pattern on water quality is the largest at the buffer scale of 1100 m riparian zone, which is an effective buffer for river governance. (2) Different spatial scales have different effects on the threshold relationship between landscape pattern and water quality. In the nonlinear regression model of landscape pattern and water quality in the buffer zone of 1100 m riparian zone, the significance and R of the equation are better than those of the sub-basin. (3) From the nonlinear relationship between landscape pattern and water quality, it is found that the landscape threshold can be quantitatively identified when the water quality changes abruptly or reaches the I ~ V water quality standard. Among them, the type-1 landscape threshold at the water quality mutation point can be used as the long-term goal of water quality protection in Dianchi Lake Basin, and the type-2 landscape threshold can be used as the short-term goal of water quality adjustment. The research results can provide a scientific basis for the governance of water environment and the rational planning of landscape pattern in Dianchi Lake Basin, and have practical significance for guiding the sustainable development of cities.
分析景观格局与水质之间的阈值关系对流域水环境治理具有重要意义。然而，先前的研究并未考虑空间尺度对阈值的影响。因此，本研究提出了考虑空间尺度效应的景观格局与水质阈值关系的思想，以解决上述问题。首先，通过冗余分析（RDA）提取滇池流域 20 条入湖河流的 9 个空间尺度（河岸缓冲区和子流域）下的景观组成面积百分比，以识别景观格局和水质的最优空间尺度。然后，采用幂回归、指数回归、二次回归和分段回归等多种非线性回归模型定量检测景观格局和水质的阈值。结果表明：（1）空间尺度对景观格局与水质的阈值关系有显著影响，在河岸缓冲区 1100m 的缓冲区尺度上，景观格局对水质的总解释率最大，是河流治理的有效缓冲区。（2）不同的空间尺度对景观格局与水质的阈值关系有不同的影响。在河岸缓冲区 1100m 的景观格局与水质的非线性回归模型中，方程的显著性和 R 都优于子流域。（3）从景观格局与水质的非线性关系中发现，当水质发生突变或达到 I~V 水质标准时，可以定量识别景观阈值。其中，水质突变点的类型 1 景观阈值可以作为滇池流域水质保护的长期目标，类型 2 景观阈值可以作为水质调整的短期目标。研究结果可为滇池流域水环境治理和景观格局合理规划提供科学依据，对指导城市可持续发展具有现实意义。
