Analysis on land ecological security change and affect factors using RS and GWR in the Danjiangkou Reservoir area, China

Abstract

The Danjiangkou reservoir area is a main water source and the submerged area of the middle route of the South-to-North Water Transfer Project of China. Thus, variations in land ecological security (eco-security) have attracted considerable attention. In this study, to evaluate the land eco-security situation of the reservoir in 1996, 2006 and 2016, we used spatial principal component analysis (sPCA) to comprehensively consider different effect factors and avoid subjectivity in the appraisals to obtain the weights and correlations between different assessment indicators. Then, we used spatial autocorrelation to analyse the spatio-temporal pattern variation characteristics. Finally, we used ordinary least squares (OLS) and geographically weighted regression (GWR) models to analyse the key factors influencing land eco-security and the concrete spatial relationships. The study results showed that the areas of the highly secure (I) regions decreased significantly from 1996 to 2016; these regions are mainly located around the reservoir. Spatially, the regions with safe eco-environments gradually tended to scatter from 1996 to 2006, while those with safe eco-security tended to cluster from 2006 to 2016. Based on the quantitative statistics and the visualized GWR model, different spatio-temporal eco-security responses to soil erosion and human activities occurred in different years. It was concluded that although the eco-security of the reservoir improved due to beneficial soil controls and water loss treatments, the expanding impact of human activities should be carefully monitored.