Abstract
Castanopsis cuspidata, which is considered as a late successional species in a warm-temperate, evergreen broad-leaved forest, has often expanded its range in abandoned secondary forests of Kyoto City. To clarify changes in species composition and diversity in the course of succession, we established two study plots with different successional stages, i.e. one was located in a mid-succecssional forest dominated by deciduous broad-leaved species, such as Quercus variabilis and Q. serrata, and the other was located in a late-successional forest dominated by evergreen broad-leaved species of C. cuspidata, and examined their species composition and diversity in relation to stem size class. In larger size classes (stem length ≥ 100 cm), species diversity was similar for the two plots. However, species composition differed between them: shrub, deciduous, and/or wind-dispersed species were more abundant in a mid-successional plot than in a late-successional. In smaller size classes (stem length < 100cm), species composition became similar and species diversity decreased in the two plots because evergreen broad-leaved tree species, such as C. cuspidata and Q. glauca, extremely increased in number in both plots. Although bird-dispersed species established in smaller size classes in the mid-successional plot, few individuals of shrub, deciduous, and/or wind-dispersed species occurred there in smaller size. These results suggest that species richness will decrease in this region without any intervention.
