Characteristics of landscape patterns of land use change in arid areas:A case study of oasis at the Baiyang River Watershed in Xinjiang

Based on the technique of Geographical Information System(GIS) and Remote Sensing(RS),the information of land use change from two periods of Landsat7-ETM+ images in 2000 and 2005 is derived.Using the methods of landscape ecology and statistical analysis,the paper selected five indices based on landscape level and class level to describe the characteristics of landscape patterns of the oasis at the Baiyang River Watershed,Fukang County,Xijiang,China.The results show that the amount of each land use type is changed with different degrees.The amount of many land use types is increased while that of meadow and unused land decreased.On the landscape level,the regional landscape heterogeneity is increased and the connectivity reduced,which presents the increase of Shannon's diversity index and Evenness Index,decrease of dominance index and increase of fragmentation index.On the class level,it shows that human disturbance on landscape is intense during the past five years,and the disturbance to artificial landscape is more intense than that on semi-natural landscape,which means that the fragmentation index of semi-natural landscape is relatively smaller while that of the artificial landscape is larger.Meanwhile,the increasing trend of the landscape perimeter-area sub-dimensions index(PAFRAC) indicates that the self-similarity of landscape patch is decreased,and the geometric shape tends to complication.As a whole,it is the intense human activities that destruct the wholeness and integrality of the natural oasis,and what's more,the disturbance of human activities is still aggravating.