ESJ56 一般講演（口頭発表） B1-02
*Vega, L.（Yokohama National Univ.）, Koike, F.（Yokohama National Univ.）, Suzuki, M.（Tokyo Univ. Forest in Chiba）
The causes of the current distribution of a Myrsine seguinii population at its northern limit were studied from topographic, geographical and historical stand points, and future land management is discussed to conserve this species. The study site is the Tokyo University forest located in Chiba prefecture. Presence and absence of individuals was surveyed by line census along the forest’s paths, making a total of 1868 surveyed 50 m segments. Current distribution was modeled by multivariate logistic regression considering as predictors elevation, slope, solar radiation, topographic wetness index, curvature, distance from the sea, watershed, land use in Meiji Era, land use in 2005, and forest age. As a result, it was clarified that the current distribution area coincides with a Pinus densiflora forest present by the end of 19th century Meiji era, where 90% of individuals of M. seguinii were found. Simulated scenarios showed that in the future the potential distribution area would decrease in the case of a complete coverage of Cryptomeria cedar plantation, and would increase in the case of evergreen broadleaf forest coverage. At the northern limit, the strong effect of past land use suggests vulnerability and difficulty in rapid recovery of the population of this species from human disturbance.