2009 Fiscal Year Final Research Report
Clarifying factors affecting above-ground floristic composition and soil seed banks for the conservation and restoration of plant species in rice paddy fields
| Project/Area Number |
19780030
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Horticulture/Landscape architecture
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| Research Institution | The University of Tokyo |
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Principal Investigator |
YAMADA Susumu The University of Tokyo, 大学院・農学生命科学研究科, 助教 (30450282)
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| Project Period (FY) |
2007 – 2009
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| Keywords | 農業生態系 / β多様性 / 空間分布 / 雑草群落 / 絶滅危惧植物 / 田植え時期 / 圃場内生物多様性 / 耕作放棄年数 |
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| Research Abstract |
Cultivated and abandoned paddy field are floristically highly diverse, but the mechanisms affecting this diversity are not clear. The following studies were carried out. First, field surveys in cultivated rice paddy fields showed that influence of land improvement intensity on floristic composition was different among different land form types. This study also implied the importance of the period of rice harvest as a factor controlling floristic composition. A germination test was, hence, carried out using surface soils of a cultivated rice paddy. The results suggest that floristic composition just after the crop harvest in autumn was strongly different according to the timing of rice harvest, while in the subsequent spring floristic composition was less affected by the timing of rice harvest in the previous year. As the third study topic, floristic composition in the soil seed banks was investigated along a chronosequence in abandoned paddy fields, where soil seed banks of rare wetland floristic species are often maintained in the surface soils. This study illustrates that duration of abandonment clearly decreased the number of wetland species, whereas no less than half species observed in the start of abandonment persisted in the seed banks under germinable condition.
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