东江流域景观格局对氮、磷输出的影响

Influence of landscape pattern on nitrogen and phosphorus output in the Dongjiang River Basin

基于实地采样水质数据与遥感解译所得土地利用数据,采用相关分析和冗余分析,从时间和空间两个尺度,探讨东江流域景观格局与氮、磷输出的关系。结果表明:(1)城镇和水域面积占比与河流氮磷含量正相关,林地和草地面积占比与河流氮磷含量负相关。(2)景观分裂指数(DIVISION)、香浓多样性指数(SHDI)、散布与并列指数(IJI)、边缘密度(ED)和斑块密度(PD)等景观指数与河流氮磷含量呈正相关关系,最大斑块指数(LPI)、蔓延度指数(CONTAG)和相似邻近比例(PLADJ)与河流总氮总磷含量负相关。(3)平水期河流水质与景观格局的相关性强于丰水期;从空间尺度来看,集水区尺度与河流水质的相关性好于缓冲区尺度;此外,总氮对于景观格局的响应比总磷更敏感。

Based on field water quality data from sampling and land use data from interpreting remote sensing imagery, we used correlation analysis and redundancy analysis to study the output relationship between landscape patterns and nitrogen and phosphorus pollution in the Dongjiang River Basin, at different spatial scales and seasons. The results are as follows.(1) In the Dongjiang River Basin, areas of town and water were positively correlated with the nitrogen and phosphorus output, while woodland and grassland areas were negatively correlated with the nitrogen and phosphorus content.(2) In the basin, landscape indices such as Landscape Division Index(DIVISION), Shannon′s Diversity Index(SHDI), Interspersion & Juxtaposition Index(IJI), Edge Density(ED), and Patch Density(PD) were positively correlated with river nitrogen and phosphorus content, while Largest Patch Index(LPI), Contagion(CONTAG), and Percentage of Like Adjacencies(PLADJ) were negatively correlated with river nitrogen and phosphorus content.(3) From the perspective of time, the correlation between water quality and landscape pattern was stronger in dry season than that in wet season. From the perspective of spatial scale, the correlation between river water quality and landscape pattern was stronger in catchment scale than that in buffer scale. In addition, nitrogen pollution was more sensitive to landscape patterns than phosphorus pollution.