| Project/Area Number |
05454604
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Environmental dynamic analysis
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
KURODA Tomio University of the Ryukyus, Division of General Education, Professor., 教養部, 教授 (00205254)
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| Co-Investigator(Kenkyū-buntansha) |
OZAWA Tomowo Nagoya University, School of Science, Associate Professor., 理学部, 助教授 (80037233)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥6,800,000 (Direct Cost: ¥6,800,000)
Fiscal Year 1995: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1994: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1993: ¥4,200,000 (Direct Cost: ¥4,200,000)
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| Keywords | Mangrove forests / Mud flats of mangrove forests / Pollen analysis / Postglacial / Climatic Optimum / Nansei Islands / Radiocarbon date / Telescopium telescopium / 熱帯気候 / 沖縄本島 / 八重山諸島 / 軟体動物群集 / ウミニナ科 / マングローブ林 / ^<14>C年代測定結果 / マングローブ林構成要素 / 昭葉樹林構成要素 / 花粉分析結果 / オヒルギ属 / メヒルギ属 / マングローブ沼生物群集 / データベース / マングローブ関連文献情報 / 種子島 / 大浦川 / 西表島 / 仲間川 |
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| Research Abstract |
Paleoclimatic and vegetational changes during the Pleistocene and Holocene in the Ryukyu Islands were inferred from pollen assmblages. Pollen analyzes of some Early Pleistocene to Holocene sections in the Ryukyu Islands show several drastic vegetational changes with climatically meaningful variations.
The Pollen assemblages in the Last Glacial period (ca.22,000 y.B.P) are dominated by the coniferous trees such as Pinus and Podocarpus, indicating that an arid climate was prevalent in the Ryukyu Islands. This evidence is consistent with the wide development of ancient dunes and paleosoil of aeolian sand origin in the islands during the Last Glacial period. The pollen sequence of the Latest Pleistocene to Holocene reveals the change of vegetation and climate from the pine forests of the Late Glacial period to the climax forests of mangrove and evergreen broad-leaved trees of the Climatic Optimum. It is suggested that the climatic condition in subtropical Ryukyu Islands around 20,000 years B.P.was not so much cool but arid than the climate of the present day.
The potamidid gastropod Telescopium telescopium (Linne) is a representative species of the tropical mangrove molluscan community in the Indo-Western Pacific marine faunal realm. Distribution of the species in the Nansei Islands during the postglacial period is examined on the basis of subfossil materials from raised beach deposits and mud flats of mangrove forests. Telescopium telescopium had been widely distributed in the Nansei Islands from Iriomote-jima to Okinawa-jima around the Holocene Climatic Optimum. However, no living individual is found from mangroves in the islands. A radiocarbon date of a well-preserved dead shell from the Funaura mangrove in Iriomote-jima indicates 330<plus-minus>80y.B.P.Thewefore, the species may have disappeared in the islands since the eighteenth centur
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