| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
Results and discussions of two examinations are shown as followed;
1) Field population dynamics of RDB animals and plants
For populations of the Giant water bugs and the Diving beetle species of Cybister, their marked and recaptured method could be applied to detect their habitat use, disparsal pattern and immigration and residual rate in examined area. Although each species use multi-habitat including rice fields, pond, irrigation way, and river in their life cycles, their main reproductive place was rice paddy fields for food production. In the case of RDB plant species, their habitat were rice paddy fields, pond and irrigation ways. However, they can grow well in dry rice paddy fields as our new finding, of which habitat is mainly permanent water such like a pond or wet-type rice fields.
2) Experiments for regenerating RDB populations in mesocosm level
In university farm, some experiments were carried out for analyzing habitat condition for each RDB populations. Especially in LISA rice cultivation method with no-tillage and legume mulching, diverse water insect populations were abundant than conventional rice production systems. Furthermore, in practical examinations in RDB population field area, diversified cropping systems with traditional crops might be available for regenerating RDB populations.
3) Tentative theory of agro-biotope
Acordings to integration of two kinds of examinations, the most effective biotope for practical situation in Japanese agriculture is sustainable rice production with lower input which reduce disturbance to RDB populations. In the case of abundant rice fields, diversified cropping systems cultivated with traditional variety such like a red-type rice under LISA.
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