Differences in spectrum reflectance and physiological indices among three typical semi-natural grasslands in Japan

To clarify the utility of spectrum reflection from plant canopy surfaces for distinguishing grassland vegetation, we tested a portable hyper-spectrometer in three typical Japanese semi-natural grasslands: Zoysia-dominated (. Z), Pleioblastus-dominated (. P), and mixed species types (. Mixed). We calculated the spectrum reflectance, its coefficient of variation (CV) and first derivative reflectance (FDR), and three physiological indices (PRI, photochemical reflectance index; CCI, canopy chlorophyll index; CI, chlorophyll index). The CV of waveform reflectance in the Mixed grassland tended to be higher than those in Z- and P-dominated grasslands. The values of PRI, CI and CCI differed among the three grasslands (. P [PRI = -0.027, CCI = 1.469, CI = 0.550] > Mixed [-0.031, 1.421, 0.459] > Z [-0.042, 1.297, 0.428]). Therefore, the CV may be used to distinguish grasslands dominated by a single species from those dominated by multiple species, while the physiological indices may be able to distinguish the grassland type by its dominant species.