著者

渡邊 定元

出版者

日本生態学会

雑誌

日本生態学会誌 (ISSN:00215007)

巻号頁・発行日

vol.55, no.1, pp.105-110, 2005-04-25

被引用文献数

2

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On Mt. Apoi, an ultrabasicosaxicolous flora with probably the greatest proportion of endemic species in the world has developed. Moreover, the flora has not been subject to succession to forest over the last 10,000 postglacial years. In the past 50 years, however, the flora of Mt. Apoi has experienced rapid deterioration and decline, mainly because of human activity-namely the illegal gathering of plant specimens-and succession to Pinus pentaphylla forest, with dramatic encroachment on beds of alpine flora. The former phenomenon has been conspicuous in Japan since 1970, when popular enthusiasm for mountain herbs began to grow. Organized illegal gathering as an occupation subsequently became pronounced, and Callianthemum miyabeanum, and other populations have declined sharply. The succession has predominantly involved invasion of ultrabasicosaxicolous flower beds on the southern slopes, primarily by Arundinella hirta, Calamagrostis sachalinensis, and Miscanthus sinensis. These have paced the continued existence of these flower beds in extreme jeopardy, and have acted as a precursor to the succession to Pinus forest. Nucifraga caryocatactes japonica bury Pinus seeds in these flower beds, facilitating sprouting. Pinus individuals reach heights of about 2.5 m within 15 years, during which time invasion by Lespedeza bicolor var. nana and Sasa apoiensis accelerates succession to forest. Global warming is certainly hastening the pace of this change. The disappearance of the flower beds is no doubt causing the loss of plants such as the endemic Hypochoeris crepidioides, which is found only on Mt. Apoi. It can be concluded that the ultrabasic area has already entered the final stages of forest succession.