景观因子对赣江水体水质的影响分析

Influence of Landscape Factors on Water Quality of Ganjiang River

流域面源污染对水体水质的影响很难被识别。研究景观因子(土地利用类型和地形因子)对河流水质的影响有助于明晰面源污染对水质的影响以及更好地管理水资源。基于冗余分析方法(RDA)和偏冗余分析方法(pRDA),该研究分析赣江主干丰枯水期水质变化,并分析1 km缓冲区土地利用组成、景观指数和地形因子3类景观因子(环境变量)对水体水质的影响。结果显示,溶解氧和镉浓度季节性差异明显,丰水期明显低于枯水期(P<0.05),其余水质指标季节性差异不明显(P>0.05),不同水质指标空间变化的异质性较大。各类景观因子对水质的贡献依次为:景观指数(13.9%~14.4%)>地形因子(4.0%~15.9%)>土地利用组成(3.7%~4.9%),景观因子对水质的影响总体丰水期高于枯水期;最大斑块指数(LPI)、景观形状指数(LSI)和平均斑块形状(SHMN)是影响赣江水质的主要景观指数,高程(HI)是影响水质的主要地形因子,未利用土地(UN)、草地(GRA)、林地(FOR)、建筑用地(BU)是影响水质变化的主要土地类型。研究结果可以为河流水质有效管理提供重要的理论依据。

The impact of non-point source pollution on water quality is difficult to identify.Studying the impact of landscape factors(land use types and topographic factors)on river water quality helps to clarify the impact of non-point source pollution on water quality and better water resources management.Based on Redundancy Analysis(RDA)and Partial Redundancy Analysis(pRDA),this study analyzed the changes of water quality in the Ganjiang River during the wet and dry seasons,and analyzed the effects of three types of landscape factors(environmental variables)of land use composition,landscape index and topographic factors in the 1 km buffer zone on water quality.The results showed that the seasonal differences of dissolved oxygen and cadmium concentration were obvious,and the wet season was significantly lower than the dry season(P<0.05).The spatial heterogeneity of different water quality indicators is large.The contribution of various landscape factors to water quality is:landscape index(13.9%~14.4%)>topographic data(4.0%~15.9%)>land use type(3.7%~4.9%).The influence of landscape factors on water quality is higher in wet season than in dry season.The largest patch index(LPI),landscape shape index(LSI)and average patch shape(SHMN)were the main landscape indices affecting the water quality of Ganjiang River.Elevation(HI)was the main topographic factor affecting water quality.Unused land(UN),grassland(GRA),forest land(FOR)and building land(BU)were the main land types affecting water quality changes.The research results can provide important theoretical basis for the effective management of river water quality.