Research On Dynamic Changes Of Landscape Pattern During Desertification In Agriculture And Pasturage Interlaced Zone Of Northern Shaanxi

By using the interpretation results of remote sensing images of 1980(aerial photo), 1997(spot), and 2007(alos), this paper analyzed the dynamic changes of landscape pattern during the desertification in Yang Qiao-pan Town during 1980-2007 based on GIS and RS technologies. A series of relative thematic maps were made for the study area. The results were as following:(1)The sand desertification intensityatYang Qiao-pan was categorized as 3: slight desertification, moderate desertification and severe desertification.The total area of research distriction was 27651.6 hm2, and the area of desertification in 1980 was 15457.6 hm2, which account for 55.9%, and the area of severe, moderate and slight desertification type were 8969.8 hm2, 3357.1hm2 and 3130.7 hm2 respectively; The area of desertification in 1997 was 16010.1 hm2, which account for 57.9%, and the area of severe, moderate and slight desertification type were 6367.3hm2, 4306.0 hm2 and 5336.7 hm2 respectively; The area of desertification in 2007 was 14211.6 hm2 hm2, which account for 51.4%, and the area of severe, moderate and slight desertification type were 4240.1hm2,5604.2hm2 and 4366.8 hm2 respectively.(2)The results showed that the desertification area appeared a tendency of increasing first and decreasing then, during the study period.The area of desertifiction area reduced by 1246.5hm2 in total. Specifically, the area of moderate and slight desertification increased 2247.1 hm2 and 1236.1 hm2 respectively, however, the severe desertification decreased 4729.7 hm2, the leading desertifiction type changed from sever to moderate one.(3)The number of desertification patches congregated and expanded, while the landscape of sandy desertification is becoming more fragmented. Fortunately, the degree of the sandy desertification had manifested declining, because the severe desertification area had decreased by 1246.5 hm2. But slight and moderate desertification had to be faced potential danger that may convert to severe desertification due to human activities and droughty climate.(4)Landscape diversity and evenness increased, and the shapes of heavy desertification patches tended to be simple,while the light, moderate ones tended to be complex, thus, the light and moderate desertification area could be more easily affected by human being.(5)Natural factors,human activities and socio-economic were main driving forces of desertification dynamic change.The increasing population and inappropriate land use were defined as main factors of desertification.