Estimating Spartina alterniflora fractional vegetation cover and aboveground biomass in a coastal wetland using SPOT6 satellite and UAV data

Spartina alterniflora (S. alterniflora) is one of the most serious invasive species in some coastal wetlands of China, and its fractional vegetation cover (FVC) and aboveground biomass (AGB) are important parameters that affect the ecology of these wetlands. Because of inaccessibility, field surveys are time-consuming, labor intensive, and difficult to implement, especially on a regional scale. Thus, satellite remote sensing and unmanned aerial vehicle (UAV) techniques are the better methods to obtain accurate FVC and AGB information in coastal wetlands. In this study, FVC and AGB of S. alterniflora were estimated based on the SPOT6 satellite remote sensing images with 6 m spatial resolution, unmanned aerial vehicle (UAV) images with 0.1 m spatial resolution, over Sansha Bay, a coastal wetland in China. In addition, some field-based samples were also collected. Results showed that most of the FVC ranged from 40% to 80%, indicated a medium-high and high level; while AGB varied from 0 to 15 kg m−2. Spatial distribution pattern of FVC and AGB were mainly influenced by the ecological and geographical environment. Meanwhile, the local distribution characteristics in the near-shore area also had close relation with anthropogenic activities. Accuracy analysis showed that, the root mean square errors (RMSE) of FVC and AGB were 0.108 and 0.415, and the coefficients of determination (R2) were 0.905 and 0.898, respectively. The results suggest that it is feasible and effective to estimate FVC and AGB of S. alterniflora in coastal wetland using SPOT and UAV data with high accuracy.