ABSTRACT
Nowadays, the global vegetation is becoming increasingly green, and there is more expressway construction in karst areas in Southwest China, however, the influence range and corresponding situation on roadside vegetation in the early stage of expressway construction in karst areas are still not clear. This study takes NDVI as the research object to indicate the vegetation change, selecting 2014 to 2019 as the research period, and taking Lipu – Yulin Expressway in Guangxi Province as the research area. The results of the analysis of the buffer zone, situation, and patterns of vegetation characteristics show that: Within the 1 km buffer zone, the area with an overall high vegetation level is the north section of the expressway, and the NDVI value of the south section decreases year by year. In addition, the vegetation level at both ends of the north and South sections of the expressway is low, which is far lower than that in the middle area. Within the 3 km buffer zone, the overall vegetation situation is higher in the north and lower in the south. The overall vegetation level fluctuates greatly in the middle section, and the trend of vegetation at the end of the south section is gradually decreasing. Within the 5 km buffer zone, the only area with a stable vegetation situation in the whole section is the north section at about 24°N. The area from 24°N to 25°N is the most obvious fluctuation of vegetation change. Both ends of the road are also the areas with the most unstable vegetation situation and the most affected.
