关键词: 石羊河流域, 植被覆盖, 景观类型

Abstract: With the support of GIS technology,and taking the Landsat/TM images as the data source,14 types of landscapes in Shiyang River basin were obtained in the study by employing the artificial interpretation method. A series of other data such as DEM,vegetation maps,and landscape maps were used. Besides,principal component analysis as well as regression methods were adopted to analyze the landscape changes in different atitude and vegetation cover,also the spatial relationship between NDVI,DEM and landscpe types were researched.The results showed that the landscape types were vertical distribution in terms of elevation,and the verticalspecific characteristics of natural elements were more obvious. In lowaltitude area,landscape distribution was more single,and the relationship between NDVI and elevation were closely associated.Relatively,in highaltitude area,the distribution of landscape was staggered.Besides,the distribution of landscape types has evident altitudinal regularity from Qilian mountains in south to desert region in north,and the distribution order is approximately as follows: glacier and snow - cold desert - water area - marsh land - grassland - woodland - farmland - residential area - overflow land - salinized land - bare soil - bare rock - sandy desert -gobi from valley to mountain top for the big vertical space of the height above the sea level. This shows that the influenced areas which are disturbed by human beings are in the low altitude. From advanced study,we find residential area is mainly distributed under 2 500 m,about 84.5% city and town residents live in the range of 1 200-3 000 m,but in the range of 3 000 and 4 000 m,residential area only occupies 16.455%. In thealtitude of 4 500 m above,there is no residential distribution.Through further research,we find the distribution boundaries and characteristics presented unbalanced.Hence the relaiontship among landscape types,NDVI and DEM were very complex,and the regression result about them were not very perfect. Seen from the whole study area,the landscape developed to the heterogeneous direction,this indicated that the proportional difference among various landscapes types was increasing,this kind of change has reflected the human activity’s influence to the whole landscape to a certain extent.However,the study provides a reference to the landscape pattern and its optimization as well as ecological planning and management. The thoughtway and results were significant for vegetation and ecological environment changes in the arid inland revier basin. Using RS and GIS technology,we can understand the spatial relationship betwwen elevation，vegetation cover and landscape Types through quantitative analysis in spatial patterns. This technology can explore idiographic landscape structures and related problems of the study area. However,the analysis data is not very ideal. For example,RS images scan cycle is long and its spatial resolution is poor. So it is difficult to get better images of grassland in the growing season under the interferential condition. The data is too complex to analyze one by one. Some results have shortages in calculating and analyzing precision. It will be ameliorated in the future study.

Key words: Shiyang River basin, vegetation cover, landscape types, NDVI, spatial relationship