Monitoring and change analysis of vegetation coverage in Ejin Oasis based on UAV-LiDAR
Vegetation coverage is the proportion of the vertical projected area of vegetation on the ground to the total area of a given statistical area,and it is an important parameter for characterizing vegetation growth and eco-system changes.To scientifically evaluate the restoration effectiveness of the Heihe ecological water transfer proj-ect,this paper takes the Ejin Oasis Populus euphratica forest as the research object and uses a UAV-LiDAR sys-tem to simultaneously obtain ultra-high resolution(GSD＜0.7 cm)visible light photos and ultra-high density Li-DAR point clouds(3 000 points·m-2)to calculate and investigate the vegetation coverage of the sample land.The relationship between vegetation coverage and the remote sensing vegetation index was established to infer the change of vegetation coverage in the Ejin Oasis from 1986 to 2023.The results showed the following:(1)The vegetation coverage calculated by LiDAR point cloud data was consistent with the visual interpretation results(R2=0.89,RMSE=0.07).Compared with the pixel dichotomy method of remote sensing,R2 increased by 0.36 and RMSE decreased by 0.03,indicating that the LiDAR point cloud can accurately calculate the vegetation cov-erage of the plot.(2)The FVC of the study area varied from 0.11 to 0.60,with an average of 0.34.The optimal model of vegetation coverage(y)and improved soil-regulated Vegetation Index(x)based on LiDAR point cloud was:y=2.53x-0.07(R2=0.68,RMSE=0.12).(3)According to the model inversion,the vegetation coverage of Ejin Oasis fluctuated during 1986-2000 and increased during 2001-2012,with an annual growth rate of 0.31％.The increase slowed down slightly during 2013-2023,with an annual growth rate of 0.19％.Theil-Sen median and M-K test trend analysis showed that after the implementation of the ecological water transport project,vege-tation cover reversed from a degradation trend to an improvement trend,indicating that the Heihe ecological wa-ter transport project has achieved remarkable results.
remote sensingUAV-LiDARfractional vegetation coverEjin Oasisecological water transport
万方数据
维普
