제주도내 멸종위기야생식물의 분포와 식생

Abstract

This paper covers the study of distribution and vegetation of Endangered Wild Plants in Jeju Island designated by the Ministry of Environment. Through this research, only 22 species were confirmed out of the 30 such endangered species known to exist in the island based on previous research and documentational record. The endangered wild plants are evenly distributed from the subpolar region at the top of Mt. Halla down to the coastal areas, and even found on the surrounding islets of the main island. This means the entire area of Jeju Island serves as an important habitat for the endangered wild plants. The distribution, however, varies with climatic zones; most of the species can be found in warm temperate zone with some occurrences in its periphery, and in temperate and polar zone of the island as well. The distribution and vegetation of the endangered wild plants confirmed in this research are as follows: 1. Some plants including Euchresta japonica, Cymbidium lancifolium, Cymbidium nipponicum, Lasianthus japonicus, Chloranthus glaber, Cymbidium kanran grow among the evergreen broad-leaved forests on valley slopes where the water supply is plenty. Cymbidium kanran, in particular, is distributed along the outer region of the evergreen broad-leaved forest, and the distribution extends even to the temperate forest of the island. Protection measures for the habitat of the species should be taken without hesitation because their breeding is done through Botrychium ternatum. The measures should include long-term plans to conserve the evergreen broad-leaved forest centered on valleys in Seogwipo where major habitats for the species are found. Gotjawal in western part of the Island with its colline geography is of importance as a major habitat of Quercus gilva. Small population can also be found in colline zones in northern and southern part of the island as well. 2. Hibiscus hamabo and Paliurus ramosissimus are limited in the western and eastern coasts of Jeju Island. This is because southern and northern part of the island is not suitable for their growing; cliffs of southern part and breaking coastal waves brought by north wind during the winter season are believed to be the reasons that restrict the growths of the two species. Hibiscus hamabo does not grow in the western part due to the low precipitation in the area as well as unfavorable soil condition which is laid on top of lava bed that is easy to get dried. 3. Isoetes japonica can be found in the coastal grassland and in the ponds near the evergreen broad-leaved and deciduous broad-leaved forests. Most of the populations are distributed in the regions lower than 400 m except the natural habitats in Hawon area. Brasenia schreberi is mainly distributed lower than the 300 m level. The new habitats of Isoetes japonica and Brasenia schreberi are discovered and believed to originate from moving germ plasm by birds, which makes it require continuous monitoring. Saururus chinensis and Utricularia yakusimensis, both grow in marsh land, are found only in western part of Jeju Island and wetlands above the 1100 m, respectively. 4. Diapensia lapponica var. obovata is distributed western and northern slopes of Mt. Halla about 1,940 meter above the sea level. This alpine plant grows in very limited environment and hence occupies small area. It is, therefore, vulnerable even to a small environmental change or ecological interference. The population can also be affected by various causes such as human or natural interruptions. Various efforts including tissue culture should be sought for to conserve these plants on site and out of the site as well. 5. Psilotum nudum, one of epiphytes, is seen even in coastal areas of Gimnyung-Ri and Gotjawal. In other words, it is found to be distributed throughout the island. Sarcanthus scolopendrifolius is limited to colline areas in southern part of the island and its surrounding islets. The habitat for Neofinetia falcata is restricted to the three locations around the middle of Seongsan Sunrise Peak Park. 6. Galeola septentrionalis and Vexillabium yakushimense are mainly distributed in Mt. Halla National Park. The good management of the National Park offers a stable condition for their growth. 7. As a result of this research, the habitats of Mankyua chejuense in Jeju were confirmed in three regions of Seonheul, Gimnyung, and Dongbok between 65 to 200 m elevation. These areas are located in eastern part of the island, and inside secondary temperate forests where dried wetland is developed in a geological setting composed of volcanic scoria, or among the small trees surrounding the secondary temperate forests. Gimnyung is found to be the largest habitat for Mankyua chejuense and a habitat located in northeast part seems to be the lowest one in Jeju. 8. Asplenium antiquum has come to the brink of extinction due to reckless gathering and it is very hard to restore the natural habitat. In order to conserve the plant, taxonomical review on species should be preceeded before the restoration based on this result is taken place. Various species such as special local plants in Jeju Island are also needed to be designated as endangered wild plants with reference to its taxonomic characteristics and specific geographical distribution. However, only some of these plants are expected to be included in the endangered wild plants list by the Korean government. When related regulations are amended, it also needs to be considered that the designation of endangered species can be expanded to the genus level for the effective management, especially for the Isoetes and Leontopodium Genus, for instance.