Abstract: With four images of Landsat TM/OLI as data sources, fractional vegetation coverage (FVC) in Qinhe Basin was estimated by dimidiating pixel model, and the spatiotemporal changes of vegetation patterns from 1993 to 2016 were analyzed using transition matrix, geo-spectrum and center of gravity migration model. The spatial variation of FVC at different attitudes, slopes, and aspects were explored based on topographic factors. The results showed that, spatially, FVC was higher in the north and lower in the south, and the vegetation with higher FVC was mainly transformed from those with lower FVC. During 1993-2016, the FVC in the Qinhe Basin showed an increasing trend with no significant fluctuation. The sum of areas with significant improvement (55.99%) and slight improvement (10.13%) were greater than that of areas with significant degradation (7.31%) and slight degradation (4.59%), reflecting good vegetation conditions. The center of gravity for FVC was migrated toward the southeast with 2.05 km, with the migrations of higher and highest FVC being the most obvious. FVC values were significantly positively correlated with elevation and slope. The area with remarkable improvement increased and then decreased with elevation and slope. The favorable terrain of vegetation in aspect was the area of the northeast, northwest and southwest. Our results will be helpful to the control of soil and water losses and ecological restoration in the study area.

Key words: GPS, GIS, Community investigation, Plot analysis