Assessing the Impact of Soil on Species Diversity Estimation Based on UAV Imaging Spectroscopy in a Natural Alpine Steppe

Grassland species diversity monitoring is essential to grassland resource protection and utilization. “Spectral variation hypothesis” (SVH) provides a remote sensing method for at pixel scale by calculating spectral heterogeneity. However, the spectrum easily affected soil other background factors in natural grassland. Unmanned aerial vehicle (UAV)-based imaging spectroscopy possibility of information removal virtue its high spatial resolution. In this study, UAV-imaging data with resolution 0.2 m obtained two sites typical alpine steppe within Sanjiangyuan National Nature Reserve were used analyze relationships between four metrics (coefficient based on NDVI (CVNDVI), coefficient multiple bands (CVMulti), minimum convex hull volume (CHV) area (CHA)) indices (species richness Shannon–Wiener index). Meanwhile, methods (based threshold linear unmixing model) investigate impact estimation. The results showed that index had better response than richness, CVMulti best correlation after removing using model. It indicated estimation ability was significantly improved information. Our findings demonstrated applicability hypothesis grassland, illustrated