Analysis of Vegetation Changes Before and After the “Meranti” Typhoon Based on Unmanned Aerial Vehicle Remote Sensing: A Case Study of Gulangyu

Typhoon is one of the most serious natural disasters in coastal areas. Efficient and accurate disaster monitoring and assessment provide essential conditions for disaster management and decision-making. This study taking “Meranti” Typhoon as an example, Unmanned Aerial Vehicle (UAV) remote sensing images were used to extract the vegetation cover information before and after typhoon intrusion, and analyzed the change of vegetation distribution pattern through calculating and comparing the their landscape pattern indices, and further through the comparison of patch difference and the calculation of landscape pattern indices of affected patches, and analyzed the distribution pattern of affected patches in Gulangyu and the disaster details. The results of the study show that: 1) Although there were many small patches in the landscape of Gulangyu, the overall pattern shows a cluster distribution; 2) Typhoon did not affect the overall distribution characteristics of the island landscape. But the proportion of vegetation landscape and non-vegetation landscape was roughly equal and balanced before typhoon, and the reduce of vegetation after typhoon made the non-vegetation landscape the dominant landscape; 3) The landscape pattern changed greatly under the influence of typhoon. The degree of fragmentation of non-vegetation patches was high before typhoon changed to the vegetation patches after typhoon, and the degree of vegetation aggregation decreased after typhoon. 4) The affected areas are regularly distributed, the open areas above the mountain or had no occlusions around were more seriously affected, and the building concentrated areas and the areas blocked by mountains were slightly affected.