Spatial distribution of vegetation and the influencing factors in Qaidam Basin based on NDVI

Abstract

The spatial distribution of vegetation in Qaidam Basin was analyzed using GIMMS (Global Inventory Modeling and Mapping Studies) / NDVI (Normalized Difference Vegetation Index) data set from January 1982 to December 2006. Based on the data of precipitation, terrain, stream systems, land use and the map of vegetation distribution in Qaidam Basin, we studied the factors influencing the spatial distribution of vegetation. The results showed that the vegetation was generally low in Qaidam Basin and there was a clear semi-ring structure from southeast to northwest. In some areas, the existence of rivers, lakes and spring belts turned this semi-ring structure into a non-continuous state and formed distinct bright spots and continuous linear features. There were four main factors that affected the spatial distribution of vegetation coverage in Qaidam Basin, i.e., precipitation, hydrological conditions, altitude and human activities. Precipitation and altitude have a correlation and determine the basic pattern of vegetation distribution in Qaidam Basin. The impacts of hydrological conditions and human activities were mainly embodied in partial areas, and often broke the pattern of vegetation distribution dominated by precipitation and altitude.