子流域景观格局对丹江口水库营养状态的影响分析  

Analysis of Impact of Sub-Watersheds Landscape Patterns on Trophic State of Danjiangkou Reservoir

作　　者：余祺 时晨燚[2] 庄娜娜 刘海 YU Qi;SHI Chenyi;ZHUANG Nana;LIU Hai(Wuhan Zhihuiyuan Environmental Protection Technology Co.,Ltd.,Wuhan 430079,China;Faculty of Resources and Environment Science,Hubei University,Wuhan 430062,China;Key Laboratory of Regional Development and Environmental Response,Hubei University,Wuhan 430062,China)

机构地区：[1]武汉智汇元环保科技有限公司,湖北武汉430079 [2]湖北大学资源环境学院,湖北武汉430062 [3]湖北大学,区域开发与环境响应湖北省重点实验室,湖北武汉430062

出　　处：《环境科学研究》2024年第8期1714-1724,共11页Research of Environmental Sciences

基　　金：国家自然科学基金项目(No.42271318)。

摘　　要：探究子流域景观格局与水体富营养化空间异质性间的关系对水源地保护具有重要意义。本文通过遥感影像和半解析方法揭示2013-2023年丹江口水库营养状态的时空变化格局,并利用SHAP机器学习解释方法,量化分析土地利用组成和景观格局指数与水体营养状态间的关系。结果表明:①丹江口水库营养状态指数呈现明显的空间异质性,以中营养为主,富营养化区域主要分布在岸线库湾区及支流附近。泄洪期水体营养状态相对优于蓄水期。②子流域的土地利用和景观格局存在明显的空间差异,在汉江上游和库区南部支流地区斑块密度(PD)、景观形状指数(LSI)和香农多样性指数(SHDI)呈低值聚集,而最大斑块指数(LPI)和蔓延度指数(CONTAG)呈现高值聚集。③土地利用组成和景观格局指数在不同时期对富营养化的影响程度不同,景观格局指数在全年、蓄水期和泄洪期的贡献度分别达到49.31%、50.99%和57.41%。其中斑块密度、林地、草地和不透水面在各时期均具有较高的影响贡献度,而蔓延度指数和香农多样性指数在蓄水期和泄洪期分别具有较高的影响。研究显示,保持子流域自然地表优势景观,降低耕地和不透水面的破碎度有助于改善水库富营养问题。Investigating the impact mechanism of land use and landscape pattern on the spatial heterogeneity of water eutrophication in subwatersheds is of great significance for water source protection.This study aimed to use remote sensing imagery and semi-analytical methods to delineate the spatiotemporal trophic status pattern of Danjiangkou Reservoir from 2013 to 2023.The SHAP machine learning method was utilized to quantitatively analyze the impact of land use composition and landscape pattern indices on water eutrophication in sub-watersheds.The research results are as follows:(1)The trophic status index of Danjiangkou Reservoir exhibits significant spatial heterogeneity,with mesotrophic conditions prevailing and eutrophication mainly located in the shoreline bay areas and tributaries.The trophic status of water body during the flood discharge period is relatively better than during the water storage period.(2)Significant spatial disparities in land use and landscape patterns are observed in sub watersheds.The aggregation of patch density(PD),landscape shape index(LSI),and Shannon diversity index(SHDI)are lower in the upstream areas of the Hanjiang River and the southern tributaries of the reservoir,while high-value aggregation of largest patch index(LPI)and contagion index(CONTAG)are evident.(3)Land use composition and landscape pattern indices show different levels of contribution in different periods.The overall contribution of the landscape pattern indices during the entire year,water storage period,and flood discharge period reached 49.31%,50.99%and 57.41%,respectively.The patch density,forest land,grassland,and impervious surface show substantial contributions across all periods,while contagion index and Shannon diversity index show higher contributions during the water storage and flood discharge periods.Maintaining the main natural landscape features in sub-watersheds and mitigating fragmentation of arable land and impervious surfaces can aid in alleviating eutrophication problem of reservoirs.

关 键 词：营养状态指数 流域 土地利用 景观格局 SHAP 

分 类 号：X524[环境科学与工程—环境工程]