著者

柴草 良悦 松下 彰夫

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.12, no.3, pp.89-94, 1962-06-01

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The islet of Kamuishu, one of the most myaterious places in Akan National Park, lies near the center of Lake Mashu (351m). It is located at 43°34′37″NL and 144°31′53″EL. Up to the present, no investigation has been reported on the vegetation of this islet. Fortunately, the writers had an opportunity to research the vegetation of this islet during the 22nd to 24th of June in 1960. The islet is composed of Quartz Andesite, in an emerged part of a central cone of the Mashu Caldera. It is surrounded by cliffs and in the northeast to south side is a steep cliff (15〜25m) which faces directly the lake. There is a rather narrow gravel shore extending in south-west to west direction in front of the cliff. The humus layer of the islet measures only 5〜10cm in the deepest part. The vegetation is mainly composed of the mixed forest dominated by Betula Ermani and Abies sachalinensis, the height of which ranges from 2 to 13m. Generally, the forest floor if covered by the shrub layer(1〜2m) dominated by Rhododendron dauricum and associated with Rhododendron Tschonoskii, Acer Ukurunduense, Menziesia pentandra, Leucothoe Grayana var. jezoensis. Sometimes Hydrangea paniculata var. intermedia forms a pure society. On the other hand, the herb layer is rather poor in species and number. The topography of this islet is not so convenient for research on the vegetation. Only two belt-transects, namely[a]and[b], and one quadrat (5m×5m), namely[A], were taken. Belt-transect[a]shows the cross section of the vegetation ; Belt-transect[b]the longitudinal section ; and Quadrat[A]situated in the Abies sachalinensis grove is the special community on this islet.