Biotic and abiotic factors affecting the structures of ground invertebrate communities in Japanese cedar [Cryptomeria japonica] dominant forests
2005
Ikeda, H.(Tokyo Univ. (Japan)) | Homma, K. | Kubota, K.
The relationships between the structures of ground invertebrate communities, forest structure, and abiotic and forest floor biotic factors in cedar dominant forests (Cryptomeria japonica) on Sado island, Japan were investigated. Three primary forests (one primary pure cedar forest and two primary coniferous-broadleaved mixed forests) and three plantation forests were chosen for this study. The diversity of invertebrate communities in the primary forests was higher than in the plantation forests. The primary forests also had a steeper slope angle, higher soil water content, higher photon flux density and canopy openness, and a thinner litter layer than the plantation forests. The structures of invertebrate communities strongly correlate with slope angle, elevation, light conditions, litter layer depth and understory species composition. In particular, light conditions and understory species composition were revealed as having a strong influence on the structures of invertebrate communities. The structures of ground invertebrate communities seem to be indirectly affected by light conditions through forest floor microclimates. Understory species seem to provide invertebrates with a food resource, sufficient protection against extreme microclimates and shelter from predators. The ground invertebrate community in one of the plantation forests was relatively similar to that in the primary forests, because as it has been managed regularly, it has a similar forest structure and light conditions, and is situated closer to some primary forests compared to the other plantation forests. Thus, this supports the hypothesis that differences in light conditions and understory species composition are the main factors affecting the diversity of invertebrate communities in primary and plantation forests.
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