Assessing temporal and spatial variations of vegetation degradation in southwest china based on multi-source remote sensing data

Southwest China is an ecologically fragile area in China. Understanding temporal and spatial variations of vegetation degradation can help to formulate measures of ecosystem protection and ecological function restoration. In this study, we evaluated vegetation dynamics and identified vegetation degradation and its spatial patterns in Southwest China, based on land cover, DEM, and GLASS LAI datasets from 2001 to 2017. The key results are: (1) Though the average LAI in Southwest China showed an insignificant trend during the study period, based on grid-scale analysis, significant declines in LAI indicating vegetation degradation were identified in some areas such as western Sichuan, western and central Yunnan, and western Tibet; (2) about 10.75% of the vegetation experienced significant degradation during the study period in Southwest China; (3) degraded vegetation was mostly distributed in high elevation areas, and about 43% degraded vegetation was located in areas with the elevation between 3500m and 5000m; (4) the dominant degraded vegetation types included grassland, alpine vegetation, shrubland, and coniferous forest. Our findings can provide valuable management implications for vegetation restoration and ecological protection in Southwest China.