Abstract
In order to clarify the effects of human disturbance and forest fragmentation on the lucidophyllous forest, we compared species composition and richness among the following three types of lucidophyllous forest in Miyazaki Prefecture in southeastern Kyushu, Japan: (1) primeval lucidophyllous forest; (2) natural lucidophyllous forest, i.e., small patches of shrine forest in which no periodic clear cutting has occurred but where there has been occasional, low-impact human disturbance as well as a high degree of fragmentation by human development; and (3) secondary lucidophyllous forest, i.e., coppices that were used as a source of firewood and charcoal. We set a total of sixty-two 100m^2 plots (11 primeval plots, 19 natural plots, and 32 secondary plots) at the study sites. In each plot, all vascular plant species were identified. The species composition clearly differed among the three forest types; that of the natural forests was intermediate between those of the primeval and secondary forests. Species composition was strongly influenced by both human disturbance and forest fragmentation. Compared to the primeval forests, species that prefer shade and mesic soil and epiphyte species were absent or rare in the natural forests. The number of species per plot for all species and that for the component species of lucidophyllous forests tended to be lowest in the primeval forests, followed in order by the natural and secondary forests. The number of species that occurred disproportionately in the primeval and natural forests when compared to the secondary forests was highly and positively correlated with forest patch area for these two types of forest, indicating that forest fragmentation causes the decrease in species richness.
