Characteristics of temporal-spatial differences in landscape ecological security and the driving mechanism in Tianchi scenic zone of Xinjiang

Abstract

The Tianchi scenic zone of Xinjiang,one of Xinjiang Tianshan Mountain's world natural heritage sites,contains well-preserved natural landscapes.Landscape ecological security is an important environmental protection indicator.In this article,gridded spatial models for the degrees of landscape ecological security in the scenic zone are constructed based on TM images from 2000 to 2010,almanacs of Xinjiang from 2000 to 2010 and the data of field survey.By using ESDA and semi-variogram for spatial analysis,and the stepwise regression methods,the characteristics and the driving forces of the evolvement of temporal-spatial differences among the individual quadrats are analyzed.The results indicate that:(1) During 2000-2010,the areas with high degrees of landscape ecological security shifted from south to north;the areas with medium degrees shifted to the center from the south and north;the areas with low degrees showed a trend of expanding from south to north.(2) From 2000 to 2010,Moran's I reflected positive spatial autocorrelation of landscape ecological security,but the level of spatial concentration decreased and was unstable with time.The local indicators of spatial association showed that the degrees of landscape ecological security exhibited a trend of change from a clustered to a random distributed pattern.(3) Within the variation range,the value of landscape ecological security exhibited anisotropy and weak spatial correlation features,as a result of combined effects of structural and stochastic factors.(4) The longitude,latitude and altitude significantly affected the degree of landscape ecological security.In small and medium landscape scales,grazing,tourism,and policy activities had major impacts on the evolvement of the landscape ecological security.