Research of land-use and land-cover change (LUCC) in the source regions of the Yellow River

The vector data of used land and covered land of the study area in 1975,1990 and 2005 were gained by means of RS and GIS technologies.Through overlay analysis,the spatial and temporal transfer characteristics of land-use and land-cover change(LUCC) were obtained.For providing scientific basis for environmental management,a statistic analysis was also made on the characteristics of change in land-use and land-cover change of every county.It is found that the environmental degradation in the source regions of the Yellow River had been very obvious from 1975 to 2005,and the main changing characteristics of land-use and land-cover change had been:cultivated land,sandy land,beaches,the reservoir and pits area increasing;marsh area reducing,high coverage grassland area reducing,medium and low coverage grassland area increasing.From the view of statistical data,the cultivated land mainly increased in Guinan,Tongde and Zeku Counties;woodland area significantly reduced in Maqin and Gande Counties;the newly increased sandy land mainly appeared in Maduo,Gonghe,Qumalai and Zoige Counties;the newly increased reservoir and pits mainly appeared in Gonghe and Guinan Counties;the marsh area mainly decreased in Zoige County.High covered grassland increased obviously in Gande and Maqin Counties,but in Maqu,Maduo,Dari,Xinghai,Aba,Zoige and Hongyuan Counties there were a large area of decreasing coverage.Therefore,in the source regions of the Yellow River,environmental protection or environmental management should be taken as targeted measures depending on specific environment in different areas.