景观格局对河流水质的影响规律及模型研究-以香溪河流域为例

It's critical important of the river water quality to the belt and the downstream area for providing high quality production and living environment. Although the studies have shown that landscape pattern characteristics greatly impact the river water quality, but the influence rule of them is not clear. So, the study of quantitative relationships between Landscape patterns and river water quality is a hotspot and difficulty of current research. It has great significance of screening key landscape pattern characteristics affect the river water quality and it also make sense to research the quantitative relations between landscape pattern and river water quality. Because the relevant results can not only be important to reveal the process of landscape patterns effect the generation and migration of river pollutants, but also can be used to instruct pollution control and so on. Based on this, choosing Xiangxi river basin in Three Gorges Reservoir Area as the study area, explore the rules of landscape patterns influence on the river water quality by using a multi-scale quantitative analysis way. In this study, methods used for data collection include: 1) Land use data will be obtained by multiple applying field investigation, remote sensing image interpretation and GIS analysis technology; 2) Multi-scale Landscape pattern indexes data will be computed by using the landscape pattern analysis software Fragstats3.3; 3) Sampling point water quality data will be acquired by combining methods of historical data collection and field investigation. Based on the data above: 1) We will firstly screening river water quality sensitive landscape pattern indexes, using a statistics test and related analysis method; 2) We will go deep into fit the quantitative model between sensitive landscape pattern indexes and river water quality by comparison three fitting models, including MLM, GLM and GAM; 3) Further more, we will explore the rules of landscape patterns influence on river water quality. This study can provide scientific basis for revealing the interaction process and mechanism of landscape elements affect river water quality, can guidance the land use optimizing, landscape planning and non-point source pollution control.

河流水质对岸带及下游区域人居环境极为重要，景观格局对河流水质往往产生巨大影响，但定量解析该影响关系却是当前科学研究的突出难点。弄清究竟哪些景观格局特征会对入河污染物质的产生、积聚与运移产生关键影响，定量解析这些关键影响的性质与特点，对指导调控入河污染物质和改善河流水质具有重要意义。本研究拟选取三峡库区香溪河流域，运用野外样带调查、遥感监测和GIS空间分析等技术手段，采用统计分析与多元线性、广义线性和广义可加模型模拟的方法，通过筛选易导致河流水质变化的景观格局指标，研究景观格局与河流水质之间的线性与非线性响应关系，建立河流水质敏感景观格局指标体系，理清景观格局与河流水质间的定量关系，辨识景观格局对河流水质的影响途径与影响模式，揭示流域景观格局对河流水质的基本影响规律。研究可为河流水质和陆地景观要素相互作用过程与机理揭示提供理论基础，为流域土地管理、景观规划和非点源污染调控提供科学依据。

景观结构、功能与过程的生态环境效应是地球科学研究的前沿领域。陆地景观要素和河流水质相互作用过程与机理研究，是科学认知景观动态的水环境影响机理的重要理论基础，对于探究河流水环境退化的“陆源”影响机制具有重要意义。基于此，本项目依据系统调查数据和历史资料，采用统计分析、遥感与GIS空间分析和模型模拟等技术手段，筛选了河流水质敏感景观格局指标；研究了景观格局与河流水质之间的定量关系，构建了景观格局与河流水质之间的多元线性模型（MLM）、广义线性模型（GLM）与广义可加模型（GAM），开展了景观格局影响河流水质相关规律的讨论与分析。主要研究结论如下：（1）定量分析了景观组分与河流水质之间的关系。结果显示，灌草地、低密度城镇、高密度林地、鱼塘和耕地等依次为河流水质敏感景观组分因子，城镇用地、耕地等人类干扰较大的景观组分，对河流水质有明显的负效应，林地、滩涂等自然景观组分，对河流水质有明显的正效应；（2）研究了景观空间配置与河流水质之间的关系。发现PD、ED、DCAD、CAI_MN、DIVISION、SHDI、SHEI、AREA_MN、SIMI_MN、CONTAG、AI等指标与河流水质关系密切；（3）构建了河流水质敏感景观格局指标体系。建立了由PD、ED、DCAD等21个指标组成的河流水质敏感景观格局指标体系；（4）建立了景观格局与河流水质之间的定量关系模型。结果显示，模型模拟精度GAM> GLM> MLM，发现了DCAD、AI等景观格局指标与河流水质变化具有非线性响应的特点；（5）对模型进行了验证，对相关机理进行了探讨。对模型模拟结果进行了校验，模拟了实验区河流水质空间分异，结果表明景观格局优化是改善河流水质的有效途径。研究结果可为科学识别景观动态的水环境影响机理提供科学依据，为流域景观规划、非点源污染调控和生态保护提供理论支持。