제주도의 양치식물상

Abstract

Factors such as geographical conditions, peculiarities of topographical and geological features as a volcanic island, and various climatic conditions of Hallasan, which is 1,950 meters above sea level and located at the central part of the island, are thought to be the main causes for the variety of pteridophyte species on Jeju. Many studies about the Jeju pteridophyte flora have been conducted so far. However since some taxa have been added or subtracted without preserved specimens being identified in most flora studies, it is difficult to identify the recorded taxa. In addition, there is a need for rearrangement of scientific names and systematic classification, as there are some Jeju pteridophyte taxa whose distribution and existence are doubtful; there are also some taxa which have been combined through taxonomic studies, and the taxonomical hierarchy of some taxa have been changed. This study was conducted not only to clarify the status of doubtful taxa included in previous studies but also to compile a list of Jeju pteridophyte species and clarify the geographical distribution of each taxa. Six thousand ninety five pteridophyte specimens were collected throughout Jeju and used for this study. As a result, it has been determined that 162 taxa occur on the island, and they belong to 28 families, 59 genera, 158 species, and 4 varieties. 15 families, 22 genera, and 33 species which had been previously recorded but were not identified in this survey have been listed as doubtful taxa. Also, 19 families, 35 genera, and 50 species were excluded from the list. These include 3 species that had been used in past studies, and 45 species that, after verification of past records and referring to features of worldwide distribution, are now believed not to be part of the Jeju pteridophyte flora. In order to preserve Jeju pteridophyte species, after quantitative evaluation and classification were concluded, a sampling of taxa worth preserving was conducted. The results are as follows: two taxa, Mankyua chejuense B.-Y. Sun et al. and Isoetes sinensis Palmer, are suggested for Rank I, comprising 1.2%, and 16 taxa, such as Psilotum nudum (L.) P. Beauv. and Colysis simplicifrons (H. Christ) Tagawa for Rank II, comprising 9.9%. In conclusion, it has been determined that climatic features have a significant influence on the distribution of pteridophyte flora in Jeju. It is recommended that monographic studies should be conducted on species whose occurrence on the island is doubtful, and other problematic species of which the nomenclature and affinities with other species are uncertain. Also, there should be additional studies on rare pteridophyte species which have an important geographic status in order to develop an effective preservation program.