Study On Spatial Distribution Pattern And Wetlands Dynamic Of Kubuqi Sandy Land

Kubuqi sandy land located in the Ordos Plateau,adjacent to the Yellow River,has a unique hydrothermal conditions.The sandy land is dotted with many rivers which are the important soueces of water supply for the Yellow River.Based on the 3S technology and combined with the field investigation of vegetation,the remote sensing images of Kubuqi sandy land in 1979,1992,2002 and 2013 were interpreted by artificial visualization,and the interpretation accuracy was 90.38%.Accordingly,both the spatial distribution pattern of Kubuqi sandy land and the dynamic change of wetland in sandy land were studied through spatial analysis,so as to provide the theoretical basis and basic data for the management of Kubuqi sandy land.The results are as follows:(1)The wetland area in Kubuqi sand decreased by 1244.5km2 and decrease of 34.29 between 1979 and 2013.The area of fixed sand and bare sand land decreased by 304.95km2 and 1021.11km2 respectively.The area of semi-fixed sand,artificial vegetation and urban construction land increased by 901.89km2,1413.69km2 and159.17km2 respectively.(2)In the past 35 years,the number of lakes and ponds reduced the fastest with the dynamic degree of-1.56%,while the area of urban construction land increased the fastest with the dynamic degree of 72.92%.(3)From the perspective of landscape type,wet meadows,swamps,lakes and ponds,rivers,bare sand are the main type of transfer,fixed sand,semi-fixed sand,artificial vegetation,urban construction land are the main transfer type.(4)The wetlands in the Kubuqi sandy land are mostly distributed in the northern part of the study area.In 1979,the wetlands showed large patch distribution.In 2013,the wetland area decreased and the patches were scattered and the water and wet meadow were broken.(5)According to the results of spatial analysis,it can be seen that in the northern part of Kubuqi sandy land,the distribution of outside-in of wet meadow,fixed sand,artificial vegetation,semi-fixed sand and bare sand land gradually formed by 2013.