1989 Fiscal Year Final Research Report Summary
Ecophysiological studies on the mechanisms for appearance and disappearance of species in successional stages.
| Project/Area Number |
62480005
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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 |
生態学
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| Research Institution | University of Tsukuba |
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Principal Investigator |
IWAKI Hideo Univ. Tsukuba, Inst. Biol. Sci., Prof., 生物科学系, 教授 (60114039)
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| Co-Investigator(Kenkyū-buntansha) |
WASHITANI Izumi Univ. Tsukuba, Inst. Biol. Sci., Assistant Prof., 生物科学系, 講師 (40191738)
OIKAWA Takehisa Univ. Tsukuba, Inst. Biol. Sci., Associate Prof., 生物科学系, 助教授 (70011682)
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| Project Period (FY) |
1987 – 1989
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| Keywords | Succession / Seedling / Microsite / Light availability / Growth / Germination / Agualic Plant / Heterophylly |
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| Research Abstract |
Mechanisms for successional appearance, replacement.and disappearance of species were studied for three ecological scenes in common Successional processes in warm-temperate Japan: 1. cyclic replacement of species in anaquatic habitat; 2. invasion of heliophilic trees into Miscanthus sinensis grassland; 3. recruitment of pioneer trees from seeds in early secondary succession. Detailed measurements on temporal and micro-spatial heterogeneity of light environment within plant communities were performed to evaluate the distribution of the microsites in which seedlings of a certain species can survive and establish. Various physiological and life-history parameters associated with growth and reproduction were measured for Quercus serrata, a representative species invading into Miscanthus sinensis grassland, Nelumbo nucifera and Nuphar japonicum, the aquatic plants involving in the cyclic species-replacement in Lake Kasumigaura, and Rhus javanica and Mallotus japonica, typical pioneers appearing immediately after forest clearing or fire. The main results and conclusions are: 1. Biomass allocation and longevity of heterophylous leaves in the aquatic plants seem to play important roles in intra- and interspecific competition and occupation of two-dimensional life space in an aquatic habitat. 2. There is a great micro-spatial heterogeneity in light availability, within a Miscanthus sinensis canopy. Although, the microsites with 'Permissible light-availability levels for survival and establishment of Quercus serrata seedlings are relatively abundant, the survival and growth of the individual seedlings depend on the light availability level of the microsite. The large seed size and the morphological and growth responses to shading have important ecological significances in successful invasion of the species into the grassland. 3.
Gap-detection in seed germination of pioneer tree species can effectively raise seedling fitness in gaps.
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