2005 Volume 22 Issue 1 Pages 1-14
Other than artificial forests, three major types of lucidophyllous (evergreen broad-leaved) forests are found in Japan, according to the degree of human impact: (1) primeval; (2) natural-those that have been subjected to occasional low-impact human disturbance, such as tree or understory cutting, and to a high degree of fragmentation by human development; and (3) secondary-coppices that was used as a source of firewood and charcoal. In this study, species composition and richness were compared among primeval, natural, and secondary lucidophyllous forests on Tsushima Island, Japan, to clarify the effects of human disturbance and forest fragmentation. The vegetation of 76 plots of 100m^2 (30 primeval, 20 natural, and 26 secondary plots) was investigated. The results of detrended correspondence analysis showed that: (1) the species composition clearly differed among the forest types; and (2) the species composition of the natural forests was in between the compositions of the primeval and secondary forests, showing similarities to both. The differences in species composition among the three forest types seemed to greatly reflect the degrees of both past human disturbance and forest fragmentation. Distylium racemosum, which has a low coppicing ability, dominated in the primeval forests, but this was not or rarely the case in the natural and secondary forests. Species richness (number of species per 100m^2) differed significantly among the forest types, from highest (primeval) to lowest (secondary). The number of all species per 100m^2 did not have a clear relationship with forest fragmentation. However, the number of species whose distributions were biased toward the primeval and natural forests was highly and positively correlated with patch area of the primeval and natural forests, suggesting that forest fragmentation is partly responsible for the differences in species richness among the forest types.
