2009 Volume 26 Issue 1 Pages 49-61
The lucidophyllous forests on Mt. Ichibusayama (Kumamoto Pref.), Kawanaka (Miyazaki Pref.), Mt. Omoridake (Miyazaki Pref.), Mt. Kurinodake (Kagoshima Pref.) and Shiratani (Yakushima Island, Kagoshima Pref.), were studied in order to clarify the species composition of the vascular epiphytes of the lucidophyllous forest and the relationship between host tree size at breast height (DBH) and species richness of the vascular epiphytes (epiphytic richness) on each host tree. In these forests, a total of 586 host trees (45 species), including 84 Distylium racemosum, 66 Persea thunbergii, 60 Quercus acuta, and 376 others were chosen as sample trees. The vascular epiphytes on the host trees comprised 37 species, including Lemmaphyllum microphyllum, Bulbophyllum drymoglossum, and Davallia mariesii. The common characteristic of the vascular epiphytes flora of the lucidophyllous forest in Japan was the dominance of ferns and orchids. The species composition of the vascular epiphytes was compared among five localities. The vascular epiphytes were assorted into 8 species groups according to the summarized table of the frequency (%) of occurrence and mean coverage (%) of each species. The species composition of the vascular epiphytes in five localities was characterized by the combination of the species groups, respectively, and each locality had a different species combination. The species composition of Mt. Kurinodake was similar to that of Mt. Ichibusayama. The species composition of Kawanaka and Shiratani was different from each other. The ordination obtained by Detrended correspondence analysis (DCA) revealed that three groups (Kawanaka, Omoridake-Mt. Ichibusayama-Mt. Kurinodake and Shiratani) of host trees (stands) were clearly different from each other. The difference of species composition among the five localities was due to the climatic conditions of the localities. The species richness of the vascular epiphytes on each host tree in five localities or in seven host tree species had a high positive correlation with host tree DBH (cm), respectively. This relationship in five localities or in seven host tree species was expressed by the equation: y=ax+b (where y is the number of vascular epiphytes, x is the DBH (cm) of the host tree, and a and b are the constants). The constants of the five localities or seven host tree species are different, respectively, due to the precipitation and humidity of the localities or the properties of the host tree bark.
