关键词: 植被综合盖度, 中高分辨率遥感影像, 变化趋势, 石漠化治理

Abstract: Vegetation restoration is the key to the control of rocky desertification in Karst areas of southwest China. The fractional vegetation cover quantifies the dense degree of vegetation and can measure the status of surface vegetation, which is helpful to further explore the trend of vegetation restoration in rocky desertification areas. This paper takes Minfeng-Dayuan small watershed in western Guizhou as the research area. Based on the image data of ZY-3 satellite, this paper uses the pixel binary model, image difference method, coefficient of variation and transfer matrix analysis to analyze the spatio-temporal evolution characteristics, change trend and stability of fractional vegetation cover in 2016 and 2021. The results show that: ① During the past five years, the area of extremely high and high vegetation cover increased significantly in the study area, leading to the improvement of the comprehensive vegetation coverage of the whole region. The large-scale conversion from low vegetation cover to high vegetation cover indicates the change from non-vegetation covered surface types such as bare rock and gravel land to vegetation covered surface types such as grassland, shrubs, and even forest land in the study area. It further shows the progress achieved in the control of rocky desertification in this area.② During the five years, the overall change of vegetation cover in the study area showed an improvement trend, and the proportion of the improved area was slightly larger than that of the degraded area, and the overall vegetation cover was relatively stable. In the degraded areas, the slight degradation is slightly greater than the slight improvement, which is caused by the expansion of urbanization and the rapid economic development. Some forest land and cultivated land are converted into construction land, and the vegetation coverage in the construction land area is reduced.

Key words: comprehensive coverage of vegetation, medium and high resolution remote sensing image, changing trend, control of rocky desertification