缙云山山地乡村景观组成对地表径流水质的影响

Effects of Mountain Rural Landscape Composition on Surface Runoff Water Quality in Jinyun Mountain

为探索山地乡村景观组成对地表径流水质的影响,以重庆市北碚区缙云山缙云村山地小流域为研究对象,基于土地利用分类,将其划分为若干汇水单元,从汇水单元角度探讨山地乡村景观的土地利用类型组成、景观格局特征与地表径流水质指标之间的关系。结果表明,研究区土地利用结构以林地为主,旱地、果园次之,空闲地所占面积比例较少;研究区山地乡村景观类型丰富,部分区域受到一定程度人为干扰,出现景观破碎化程度增加、连接度降低等景观问题;研究区不同土地利用类型面积占比与地表径流水质指标之间呈显著或极显著相关关系,其中旱地、果园、菜园、农村宅基地、坑塘水面面积占比与之呈正相关关系,林地(常绿阔叶林、针阔叶混交林、竹林面积)占比与之呈负相关关系;研究区不同汇水单元景观格局指数与地表径流水质指标之间呈显著或极显著相关关系,其中斑块密度、边缘密度、景观分割指数、多样性指数与之呈正相关关系,斑块平均面积、最大斑块指数、蔓延指数、斑块内聚指数与之呈负相关关系。

In order to explore the effect of mountain rural landscape composition on surface runoff water quality,the mountain watershed of Jinyun Village,Beibei District,Chongqing was studied,which was divided into several catchment units based on land use classification,and the relationship between land use types,landscape pattern characteristics and surface runoff water quality indexes of mountain rural landscape was discussed from the perspective of catchment units.The results showed that the main land use structure in the study area was forest land,followed by dry land and orchard,and the proportion of idle land was less;the mountain rural landscape types were rich,and some areas were subject to some degree of human interference,resulting in landscape problems such as increased landscape fragmentation and decreased connectivity;the area proportion of different land use types and the surface runoff quality index were significant or extremely significant correlation,the area proportion of dry land,orchard,vegetable garden,rural house-site and pits surface area was positively correlated,and the area proportion of forest land(evergreen broad-leaved forest,coniferous broad-leaved mixed forest and bamboo forest)was negatively correlated;the landscape pattern index of different catchment units was significantly or extremely significantly correlated with the surface runoff water quality index,among which patch density,edge density,landscape division index and diversity index were positively correlated,while patch average area,maximum patch index,contagion index and patch cohesion index were negatively correlated.