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

Abstract

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.