基于LDI的土地利用类型与湿地水质的相关性:以苏州太湖三山岛国家湿地公园为例

以苏州太湖三山岛国家湿地公园为例,探索不同时空条件下土地利用类型整体与水质之间的相关关系.使用主成分分析计算出每个采样点的水质综合指数,基于GIS空间分析技术计算表征土地利用类型综合效应的景观开发强度指数(landscape development intensity,LDI),运用Pearson相关分析探讨水质与土地利用类型之间的整体相关性.结果表明,水质随着湿地公园空间分布不同而有较大的差异,研究区西部水质较好,东部水质较差;建设用地与水质综合指数存在明显的正相关,自然水体则与水质综合指数呈显著的负相关;缓冲区半径为100、150、200、250、300、350、400、450和500 m的LDI综合指数与水质综合指数的Pearson相关系数分别为0.641、0.678、0.691、0.685、0.691、0.695、0.680、0.653和0.649(P0.01),它们之间存在显著而稳定的相关性,可以体现出多种土地利用类型对湿地水质的整体影响,部分克服了单项土地利用类型表达不完整、难以解释水质变化的不足.

Correlation Between LDI-based Land Use Types and Water Quality in Sanshan Island of Taihu Lake National Wetland Park, Suzhou

Sanshan island of Taihu Lake National Wetland Park in Suzhou was taken as a case study to explore the relationship between land use types and water quality under different spatial and temporal conditions.Firstly,principal component analysis was used to calculate the comprehensive index of water quality for a given sampling site.Secondly,landscape development intensity index (LDI),which can represent combined effects of land use types,was calculated based on GIS spatial analysis technology.Finally,overall correlation between water quality and land use types was obtained by using Pearson correlation analysis.The results showed that the water quality varied with the spatial distribution of the wetland park.Totally,water quality of west region was good and water quality of east region was poor;Built-up land and water quality integrated index exhibited obvious positive correlation.And natural water and water quality index was significantly negatively correlated;By building relationship of water quality index and LDI index within 100,150,200,250,300,350,400,450 and 500 m radius buffer,Pearson''s r values between them were 0.641,0.678,0.691,0.685,0.691,0.695,0.680,0.653 and 0.649 respectively (P<0.01).These statistics indicated obvious and stable overall correlation between land use types and water quality.This can reflect a variety of land use types'' comprehensive effects on wetland water quality,and partly overcome the weakness of incomplete and difficult explanation for water quality changes with single type of land use.