郴州市郴江河流域水质与土地利用关联的空间异质性分析

Spatial heterogeneity of the correlation between water quality and land use in the Chenjiang River basin,Chenzhou City

为了研究郴州市郴江河流域水质与土地利用关联的空间异质性特征,采集了2021年9月流域水质与高分遥感数据;通过不同类型、不同尺度的流域缓冲区划分,计算土地利用组分及各地类斑块形状、尺寸及分布等景观配置;利用单因子、多因子相关性分析,进行区域土地利用对水质的空间异质性影响分析。结果表明:①在水质与土地利用单因子空间异质性关联分析中,圆形缓冲区的普适性优于河岸缓冲区,而河岸缓冲区在分析建筑用地占比对各水质参数的影响方面起补充作用。在多因子空间异质性关联分析中,河岸缓冲区土地利用对水质参数的解释率普遍高于圆形缓冲区,圆形缓冲区土地利用对水质参数的总解释率最大值出现在半径700 m尺度。②不同土地利用组分对水质的影响不同,耕草地、林地、水域面积占比与水质呈正相关关系,建筑物、裸地呈负相关关系,其中耕草地与建筑用地对水质影响最大;在进行土地利用规划时,要考虑到土地利用组分的影响,合理分配人工地物和自然地物面积占比。③不同土地利用景观配置对水质影响不同。其中反映斑块形状与尺寸的景观形状指数(landscape shape index,LSI)、最大斑块指数(largest patch index,LPI)对水质存在负面影响,反映斑块分布的散布与并列指数(interspersion and juxtaposition index,IJI)和水体氨氮(ammonia nitrogen,NH3-N)含量在小尺度内呈负相关。在进行土地利用规划时更要考虑到景观配置的合理性,例如要控制缓冲区内优势地类斑块大小。研究结论找出了最能影响水质的缓冲区大小,揭示了最能解释郴江河水质的土地利用组分及其景观配置,为郴江河水质恶化的科学治理措施提供选择依据,对水环境保护有一定意义。

This study investigated the spatial heterogeneity of the correlation between water quality and land use in the Chenjiang River basin of Chenzhou City using the water quality and high-resolution remote sensing data of the river basin in September 2021.Based on the division of river basin buffer zones by different types and scales,this study calculated land use components and their landscape configurations,such as the shape,size,and distribution of patches.Then,this study analyzed the spatial heterogeneity effect of regional land use on water quality through single-factor and multi-factor correlation analyses.The results are as follows:①In the single-factor correlation analysis of spatial heterogeneity between water quality and land use,circular buffer zones showed higher universality than riparian buffer zones,which played a complementary role in analyzing the effect of built-up land occupation on water quality parameters.In the multi-factor correlation analysis of spatial heterogeneity,the land use presented generally higher interpretation rates for water quality parameters in riparian buffer zones than in circular buffer zones,with the maximum total interpretation rate of land use for water quality parameters in circular buffer zones occurring on a scale of a radius of 700 m.②Different land use components had different effects on water quality.The proportions of cultivated land,grassland,forest land,and water areas correlated positively with water quality,while those of building land and bare land correlated negatively with water quality.Among them,cultivated land,grassland,and building land had the most significant effects on water quality.Land use planning should consider the influence of land use components and reasonably allocate the proportions of artificial and natural features.③Different landscape configurations had different effects on water quality.The landscape shape index(LSI)and the largest patch index(LPI),which reflect the shape and size of patches,had negative effects on water quality.Furthermore,the interspersion and juxtaposition index(IJI),which reflects the distribution of patches,correlated negatively with the ammonia nitrogen(NH3-N)content in water bodies on a small scale.Land use planning should consider the rationality of landscape configurations.For example,it is necessary to control the sizes of dominant land patches in the buffer zones.This study identified the buffer zone size that influences water quality the most and the land use components and landscape configurations that can explain the water quality of the Chenjiang River the best.Therefore,this study provides a basis for selecting scientific control measures for the deterioration of water quality in the Chenjiang River,showing certain significance for water environment protection.