Estimating fractional cover of non-photosynthetic vegetation for various grasslands based on CAI and DFI

Non-photosynthetic vegetation (NPV) is a vital component of terrestrial ecosystems and an important indicator of grassland degradation, therefore, it is of great significance to realize its accurate evaluation. Here, we analyzed spectral characteristics of NPV of different biomass types in undisturbed vegetation (herb, subshrub and shrub), and established relationship models among dead fuel index (DFI), cellulose absorption index (CAI) and fractional cover of NPV (fNPV) based on ground hyperspectral data; then, fNPV of four grassland types were evaluated based on the models. Our results showed that: (1) NPV reflectance exhibited similar change trends for herb, subshrub, shrub, and a mixed type, although there were significant differences among values, (2) DFI and CAI, CAI and fNPV, DFI and fNPV were significantly positively correlated (p