Comparison between Primeval Lucidophyllous Forest and Secondary artificial forests with regard to species composition and species richness in the Upper Reaches of the Ayaminami River, Miyazaki Prefecture, Southwestern Japan

Abstract

A primeval lucidophyllous forest surrounded by large secondary lucidophyllous and artificial coniferous forests is distributed in the region of the upper Ayaminami River in Miyazaki Prefecture of southwestern Japan. This area is excellent for studying the differences in species composition and species richness between primeval forest and secondary/artificial forests. Sixteen species groups (differentia lspecies) were recognized on the basis of phytosociological fidelity degree of 5. The primeval lucidophyllous forest was characterized by the presence of Buibophyilum drymoglossum, Chloranthus spicatus, Selaginella involvens, Eria reptans, Asplenium wilfordii and other species, and by the absence of Symplocos lucida, Symplocos prunifolia, Neolitsea sericea and other species that are the main elements of secondary lucidophyllous forest .The secondary lucidophyllous forest was differentiate dby the presence of Mallotus japonicus, Zanthoxylum ailanthoides, Rhus succedanea, and Styrax japonica, which were summergreen trees. The artifici aClryptomeria japonica and artifici aPlinus forests were characterized by the dominance of Cryptomeria japonica and Pinus spp., respectively. The mean number of total species and the mean number of lucidophyllous elements per stand in the four forests, which were indicative of the species richness, ranged from 62.6 and 46.6 to 60.4 and 33.8, respectively. The species richness of the secondary/artificial forests was 56-68% that of the primeval forest. Ferns and orchids play an important role in the species richness of primeval forest. It appeared that the secondary/artificial forests did not posses the capacity to well maintain the species richness of lucidophyllous elements