1996 Fiscal Year Final Research Report Summary
A General Theory for Species Coexistence in Various Forests : the Diffusion Model for Plant Communities
| Project/Area Number |
06640822
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
生態
|
|---|
| Research Institution | HOKKAIDO UNIVERSITY (1996)
The University of Tokyo (1995)
Tokyo Metropolitan University (1994) |
|---|
Principal Investigator |
HARA Toshihiko Hokkaido Univ., Institute of Low Temperature Science, Professor, 低温科学研究所, 教授 (80183094)
|
|---|
| Project Period (FY) |
1994 – 1996
|
| Keywords | competition / asymmetric competition / symmetric competition / succession / coniferous trees / broad-leaved trees / diffusion model / size structure |
|---|
| Research Abstract |
I investigated growth dynamics, competition and recruitment processes in the following climax forests : sub-boreal forest on Mt.Taisetsu, Hokkaido (Abies sachalinensis, Picea yezoensis), warm-temperate forest in Miyakejima island, Tokyo (Castanopsis cuspidata), sub-alpine forest on Mt.Kitayatsugatake in Shinshu (Abies veitchii, A.mariesii) ; and in an early-successional Betula ermanii forest in Ashibetsu, Hokkaido. I analyzed the growth data based on the diffusion model (Hara 1984), and found that (i) in the climax forests, both intra-and interspecific competition between canopy trees was much weaker than that between saplings and the mode of competition was usually symmetric ; (ii) sapling recruitment process was determined by the species-specific combination of stand structural attributes such as fallen-log abundance, Sasa density in the forest floor ; (iii) in the early-successional Betula ermanii forest, competition between canopy trees was intense and asymmetric ; (iv) these results obtained in the field were confirmed by the canopy photosynthesis model, i.e.broad-leaved trees tend to show intense and asymmetric competition while coniferous trees weak and symmetric competition ; (v) it was shown by a theoretical model that the effect of disturbances on spatial pattern dynamics of plant communities is larger under symmetric competition than under asymmetric competition ; (vi) it was concluded that growth and spatial pattern dynamics are governed by deterministic factors (competition) in early-successional forests while these are governed by stochastic factors (disturbances) in climax forests.
|
