Habitat Analyses of Six Threatened Plant Species in a Moist Tall Grassland Based on Hyperspectral-Remotely Sensed Data

抄録

　The Watarase Wetland is the largest lowland wetland (approximately 3,300 ha) remaining on the Honshu mainland of Japan, mainly composed of moist tall grasslands dominated by Phragmites australis (Cav.) Trin. ex Steud. and Miscanthus sacchariflorus (Maxim.) Benth., with the under-layer inhabited by more than 650 vascular plant species, including more than 50 threatened species listed in the national Red List. We analyzed the effectiveness of two sets of hyperspectral-remote sensing parameters ‘shoot density of each of P. australis and M. saccahriflorus’ and ‘summed shoot density and shoot density ratio of both species’ to map potential habitats of six threatened plant species. Analysis by generalized linear models (GLMs) showed that the parameters related to shoot densities of P. australis and M. sacchariflorus had significant effects on abundances of all species. Accuracy values evaluated by adj. R² were the same between the models for the two parameter sets in the cases of all threatened species. The models for two species with high occurrence and abundance, Galium tokyoense and Ophioglossum namegatae, yielded high accuracy (adj. R² > 0.7). We also found an autocovariate term related to the spatial autocorrelation of species abundance to be important in all the species examined. These results suggest the effectiveness of hyperspectral-remote sensing of shoot densities of P. australis and M. sacchariflorus in habitat modeling of locally abundant threatened species in moist tall grasslands.