Abstract:In order to reveal the temporal and spatial variation on vegetation coverage and provide evidence for ecological environment construction on the upper Anning River, the temporal and spatial variation on vegetation coverage, during 1999—2010, on the upper Anning River was extracted and analyzed based on two periods of remote sensing images (TM in 1999, ETM+ in 2010), which was based on RS and GIS technology. Meanwhile, combined with Aster DEM data, the vegetation distribution and its variation characteristics in different altitude and slope regions were also analyzed. The results showed that the vegetation coverage condition in study area overall was good. And the area of vegetation coverage (fc) above 0.5 was more than 60%. Besides, a trend emerged during 11 years in the study area that vegetation cover overall increased. The area of first grade vegetation coverage (fc≥0.7), second grade vegetation coverage (0.5≤fc<0.7) and third grade vegetation coverage (0.3≤fc<0.5) increased by 1.24%, 4.36% and 2.28%, respectively. However, the area of fourth grade vegetation coverage (0.1≤fc<0.3) and fifth grade vegetation coverage (fc<0.1) reduced by 25.72% and 12.28%, respectively. Low vegetation coverage was mainly distributed in relatively low altitude areas. With the increase of altitude, vegetation cover increased firstly and then decreased. Variation on vegetation coverage that low vegetation coverage was transformed into high vegetation cover degree was obvious in regions below 3000m, especially lower than 2500m. With influenced less by human activity, vegetation cover above 3000m seemed to hold relatively little change. High vegetation cover was mainly located in high slope regions, while low vegetation cover was mainly located in relatively moderate slope regions. An obvious variation on vegetation coverage was concentrated in regions with slope range from 25° to 45°, regions below 25° ranked secondly. While no obvious change of vegetation cover in regions with slope above 45° appeared, with less influenced by human activity. Under hydrothermal condition，the vegetation coverage on aspect is sunny slope (135°~225°)> half sunny slope (45°~135°)> half shady slope (225°~315°)> shady slope (0°~45°, 315°~360°); the vegetation coverage increased in each aspect from 1999 to 2010, and sunny slope increased significantly while no obvious increase on shady slope.
