| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2004: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2001: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
The use of data for present-day vegetation, modern and pre-tephra pollen have, together, allowed reconstruction of the vegetation history in and around montane mires in northern Japan. The modern pollen data from four mires were compared with the surrounding vegetation, showing that pollen of Acer, Salix, Ilex and Lysichiton, which form scrub or thicket, indicate the limit of the mires. Drosera, Liliaceae, Sanguisorba and Sphagnum were concluded to be local elements. They were necessarily present when their pollen was present. Different histories of mires in the same region were shown : the mire which has become drier (Ohse-yachi) in this 1100 years, and those which have developed (Shimo-kenashi and Yabitsu-yachi).
Temporally precise pollen data from the Yabitsu-yachi Mire were applied to reconstruction of the vegetation recoveries after volcanic activities. The Towada-Chuhzeri (To-Cu) Tephra, which is about 10cm thick and includes pumice of 1cm in diameter, severely affected the mire vegetation. After the tephra fall, the drier herbaceous vegetation or scrub were formed and maintained more than 300years. Falls of finer tephra (Towada-a (To-a) and Baegdusan-Tomakomai (B-Tm)) of less than 6cm thick did not change the dominant of the mire, Cyperaceae. However, diversities of component species were declined and more than a few decades were thought to be necessary for the recovery of the diversity.
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