Distribution and Vegetation Structure of Genus Cymbidium (Orchidaceae) in Jeju Island

Abstract

This study was carried out to investigate the range of distribution and vegetation structure of habitats of genus Cymbidium which is distributed in Jeju Island, Korea. This genus is distributed in tropical and subtropical Asia and North Australia. In Korea, there are six species [i. e. C. goeringii (Rchb. f.) Rchb. f., C. kanran Makino, C. lancifolium Blume var. aspdistrifolium (Fukuy.) S. S. Ying., C. macrorhizum Lindl., C. nagifolium Masam. and C. ensifolium L.], which were also distributed in Jeju Island. The habitats of this genus ranged between 16 meter and 574 meter above sea level in Jeju Island. C. macrorhizum had the broadest altitudinal range (16-574 meter above sea level), whereas C. ensifolium, C. nagifolium and C. lancifolium var. aspidistrifolium had the narrow altitudinal range. According to the classification analysis by TWINSPAN, the plant communities were divided into five groups of Castanopsis sieboldii community, Castanopsis sieboldii-Pinus thunbergii community, Pinus thunbergii-Quercus acutissima community, Pinus thunbergii community and Quercus glauca-Aphananthe aspera community. Three species, C. kanran, C. nagifolium, and C. ensifolium inhabited Castanopsis sieboldii community and C. lancifolium var. aspdistrifolium inhabited Castanopsis sieboldii-Pinus thunbergii community. C. macrorhizum inhabited Pinus thunbergii community, Pinus thunbergii-Quercus acutissima community and Quercus glauca-Aphananthe aspera community. C. goeringii inhabitated Castanopsis sieboldii-Pinus thunbergii community and Pinus thunbergii-Quercus acutissima community. The populations of the genus Cymbidium have been extremely decreased due to illegal collection in Jeju Island. Especially, the distribution range of C. kanran, C. nagifolium, and C. ensifolium was narrow and limited to evergreen broad-leaved forests, therefore, conservation plans are needed for the protection of these species.