Developing a mapping method for selecting biodiversity conservation priority area and for invasive species measures in the oceanic islands

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To conserve endangered plant species in oceanic islands of Tokyo, we studied precise biogeographic distribution, community structures, and light environment of individuals of Viburnum species. V. brachyandrum is distributed from Oshima Island(northern limit) to Hachijojima Island, V. japonicum is from Toshima Island to Hachjojima, and V. japonicum var. boninsimense is limited to the Ogasawara Islands. The habitat was in the primary forests with typically high atmospheric moisture, and in relatively bright environment(RPPFD> 13%). However, such environment has decreased due to intensive land-use and vegetation changes after human inhabitation. Herbivory on saplings by feral goats in Chichijima Island is severe, hens the historical evidence of specimens showed that the local population of V. j. boninsimense has become extinct from Hahajima Island due to alternative reasons in the past few decades. Extensive plantations of Camellia japonica in Toshima and invasion of an exotic deer, Muntiacus reevesi in Oshima Island are also serious, and we found out that even though some of the endangered species are located in the National Parks, not only their present distribution pattern, but also their past distribution must be considered when delineating the new protected areas.