THE DRIVING FORCES OF LAND USE/COVER CHANGE INTHE UPSTREAM AREA OF THE NENJIANG RIVER

Key words: 
• the upstream area of the Nenjiang River /
• land use degree change /
• Thiesson polygon method /
• drivingforces

Abstract: Based on the Landsat and Landsat 7 TM images, the land use/cover change was detected in the up stream area of the Nenjiang River between 199 and 2000. With the spatial analysis techniques of GIS, the maps of land use degree and its change within this period were produced. To identify the causes of changes, elevation and slope were regarded as the main natural influencing factors and were transformed from coverage format to grid format within GIS. The Thiesson polygon method was used to the spatial allocation of socio-economic factors including human population, live stock numbers, mechanizing power of farming and the nearest distance from the changed pixel to the trunk stream and to main settlements, thereby the spatial relationship between land use degree change and socio-economic factor variation was analyzed. According to results of the spatial correlation, the determinants of changes in land use/cover, i.e. eleva tion, slope, population density change, livestock increase were extracted quantitatively in this area. At last, the spatial multi-linear regression model of land use degree change was developed as follows: △La = 11.037-4.12 * elevation-0.298 * slope + 0.292 * △population + 2.96 * △livestock.