• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.4
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• pp.87-98
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• 2015

The natural monument forests (no.374) located at Pyeongdae-ri in Jeju island are described and classified by using phytosociological methods and numerical analysis. The purpose of this paper is to identify the ecological character of Torreya nucifera forests between natural habitat and artificial habitat, as well as their spatial and phytogeographical distribution in the Korea. The comparison of forests between Pyeongdae-ri and other regions was analyzed by using a non-metric multidimensional scaling analysis (NMDS) and hierarchical clustering. On the basis of the 12 phytosociological $relev{\acute{e}}s$, the vegetation of T. nucifera dominant forest in Jeju island was arranged in one syntaxon (Alangium platanifolium-Torreya nucifera community included typicum and one subcommunity) within Camellietea. The community of T. nucifera dominant forests were characterized floristically and ecologically. We discussed diagnostic species with references, and proposed a few important diagnostic species (Ilex crenata for. microphylla, Acer palmatum, Zingiber mioga, Mercurialis leiocarpa, Osmorhiza aristata, Mecodium wrightii etc.) to explain condition of the habitat and synecological character. The communities were described by concerning their edaphical and syndynamical niche; we discussed their total distribution in Korea. In most forests they are widespread in Korean peninsular and their distribution is primarily determined by artificial plantation and periodical management. The forests consisted of T. nucifera have developed from natural environment element and artificial management. As a result they have very unique characters with the floristic, structural characterization and distribution. Furthermore, we identified that they need to apposite management for sustainability.

• Microbiology and Biotechnology Letters
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• v.48 no.1
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• pp.57-63
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• 2020

Over the past 20 years, global warming has transformed the marine ecosystem of the Jeju Island into a subtropical zone making it conducive to the production of tropical fishes. Recently, the balloon fish (Diodon holoanthus) has been found off the coast of the Jeju Island. In this study, we analyzed the diversity of its intestinal microorganisms as a representative for the surrounding environment. In addition, the isolates were evaluated for their antibacterial activity. A total of 161 strains of various species were identified and isolated using 16S ribosomal RNA gene sequence analysis. They were separated into three groups, of which Phylum Proteobacteria was found to be the most dominant with 91% sequence similarity. This includes the class γ-proteobacteria that is made up of twelve genera and twenty-four hundred species. The second group comprised strains of the genus Vibrio, made up of 35% Photobacteria, 32% Shewanella, and 6% Psychrobacter. It was also determined that 4% of the isolates were Acinetobacter, 3% were Enterovibrio, while Moraxella_g2 accounted for 1% of the total isolates. Class α-proteobactera includes five genera and five species; Brevundimonas, Allorhizobium, Pseudoceanicola and Erythrobcter, each accounting for 1% of the total isolates. The Firmicute strains belonged to six genera and ten species. 5% of the strains were Terribacillus, while Paenibacillus, Salinicoccus, Staphylococcus and Streptococcus accounted for 1% each of the total isolates. Actinobacteria accounted for the final phylum with strains belonging to three genera and ten species with Janibacter, Micrococcus and Isoptericola each accounting for 1% of the total isolates.

• The Korean Journal of Malacology
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• v.30 no.1
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• pp.95-99
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• 2014

In the present study, we surveyed the molluscan fauna in a lagoon located near Seong-san harbor on the east coast of Jeju Island in July 2012. For the survey, a $25{\times}25cm$ quadrat was deployed over 3 randomly selected sites in the intertidal area of the lagoon. Sediment from the surface to a depth of 25 cm in the quadrat was removed and sieved using a 1 mm mesh sieve. All molluscan fauna retained on the sieve was identified to the species level. From the survey, 25 species of mollusca belonging to 2 orders and 16 families were identified. Species richness, in terms of total number of species, was found to be the highest at sampling site 1, where the substrate was composed of coarse sand and some rocks, while it was lowest at sampling site 3, composed of compact fine sand. Regardless of the type of substrate at the sampling sites, the mud-creeping snail Batillaria cumingii (Crosse, 1862) occurred at a high density, ranging from $324-468ind./m^2$. The luciniid bivalve Pillucina pisidium also occurred at a high density at sampling site 1, at $336ind./m^2$, while the density of this species was only $4ind./m^2$ at sampling site 3. The Manila clam Ruditapes philippinarum could be found at all 3 sampling sites with very low density ranging from $16-48ind./m^2$. The density and species richness of molluscs observed in this study was lower compared to the previously reported molluscan fauna in Jeju Island, suggesting that further investigation needs to be carried out to conserve the unique marine lagoon ecosystem in Jeju Island.

• Korean Journal of Environment and Ecology
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• v.28 no.2
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• pp.205-214
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• 2014

The purpose of this study is to suggest vegetation management method as the cultural landscape forest of Dongbaek Island which is the district monument. The study area was $20,000m^2$ around the peak area in management as the nature sabbatical area. Vegetation structure type was classified with the criteria of topography, vegetation, management and the management plan was derived from the vegetation structure analysis according to the types. Vegetation structure types were Management-Camellia japonica, Non-management-Eurya japonica, Non-management-Rugged area-Eurya japonica. As the result of vegetation structure, Pinus thunbergii dominated in canopy layer and Camellia japonica and Eurya japonica dominated in Type I and in Type II and III, respectively. Especially, Machilus thunbergii as the climax species in the warm temperate forest were distributed centering shrubs, and as the result of distribution of diameter of breast height, middle size of Celtis sinensis and Machilus thunbergii were distributed in type I, II. Machilus thunbergii were distributed in range of 4 to 44 individuals through the all types. Mean age of canopy layer was 66 year-old and sub-canopy layer was 22.9 year-old. Shanon's species diversity was analysed from 0.5472 to 0.8646. As the vegetation management direction of Dongbaek island, managed Camellia japonica forest was suggested to maintain the regular management and non-managed Eurya japonica forest was required to remove the Eurya japonica and plant the Camellia japonica. In case of non managed Eurya japonica forest in rugged area, vegetation succession was required to laurel forest.

• Journal of the Korean association of regional geographers
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• v.13 no.6
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• pp.609-622
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• 2007

This paper examines the lava tubes designated as a natural monument in Jeju Island, and then makes the several suggestions for conserving and managing them. The cave entrances should be scientifically and strictly managed to prevent the deterioration, and to preserve the interior ecosystem, of the lava tubes. The land use and vegetation of the ground surface over the lava tubes should be also systematically managed; the destroyed sand dunes must be recovered for the development of speleothem in the lava tubes, and the plants with deep roots must be removed for the prevention of ceiling collapse. The provincial authorities should manage the ground surface over the lava tubes as a public land to remove the factors threatening the stability of the lava tubes. Since the roads crossing the ground surface are likely to cause the collapse of the lava tubes, new roads bypassing the caves need to be constructed, and warning signs should be also installed at the traverse points. A monitoring system on the cultural properties protection area over the lava tubes could be effectively established by encouraging residents to participate the conservation program of lava tubes. Since the falling blocks from ceilings have been usually observed in the lava tubes, it is urgent to examine their stability. In particular, the dangerous sections must be continuously monitored for taking a quick measure against the collapse. The air environments of lava tubes need to be scientifically analyzed based upon the long-term observations. The lighting equipments must be improved to minimize the green pollution in the lava tubes open to the public. The numbers of visitors should be also controlled to prevent the destruction and contamination of lava tubes caused by a large number of visitors.

• Korean Journal of Plant Taxonomy
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• v.46 no.1
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• pp.83-116
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• 2016

This study was carried out to investigate the flora and vegetation of Yokjido Island in Tongyeong-si, Korea. Vascular plants collected six times (from March of 2015 to January of 2016) were identified as 547 taxa in total, including 113 families, 354 genera, 487 species, four subspecies, 50 varieties, four forms and two hybrids. The first records from this region contained 314 taxa. In the flora of this area, endemic Korean species numbered eight taxa, and the red list of vascular plants according to the IUCN valuation basis numbered six taxa. In addition, 86 taxa of floristic regional indicator plants specially designated by the Ministry of Environment are included. Among the species investigated in this survey, 99 taxa were identified as specific species bio-geographically as compared floras of other terrestrial regions; 97 taxa of plants in southern areas and two taxa of limited distribution plants on the Korean Peninsula. In all, 74 naturalized plants were recorded in the investigated area. Samples of the forest vegetation of Yokjido Island were mainly classified as Pinus thunbergii community and the Alus firma community. Vertical structures of the communities were stable, and a DBH-class analysis showed that the dominant tree species would be maintained. If disturbance factors such as thinning could be halted, the composition of woody species and herbaceous species would change.

• Journal of Life Science
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• v.22 no.10
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• pp.1384-1391
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• 2012

Five coastal plant species, Artemisia fukudo, Aster sphathulifolius, Plantago camtschatica, Sedum oryzifolium, and Setaria viridis, were collected from the coastal region of Ulleung Island (Ulleung-Do, South Korea). Thirty-six endophytic fungi were isolated from the roots of these plants, and all were identified by using PCR with the following specifications: internal transcribed spacer 1 (ITS1), 5.8S rRNA, and ITS2 regions. Phylogenetic analysis indicated that all fungal strains belong to the phylum Ascomycota and comprise four orders (Capnodiales, Eurotiales, Hypocreales, and Pleosporales). Among all the identified species, the Eurotiales species were more abundant than species in the other orders. Nine different genera (Alternaria, Aspergillus, Cladosporium, Exserohilum, Fusarium, Neosartorya, Penicillium, Phoma, and Pyrenochaeta) in the four orders were confirmed. Penicillium and Aspergillus species were the most dominant species among the endophytic fungi isolated from the coastal plants. Shannon's diversity index (H') ranged from 0.684 to 1.609, and the endophytic fungi in S. oryzifolium was more diverse compared to the endophytic fungi in the other plants.

• Journal of Wetlands Research
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• v.12 no.2
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• pp.35-46
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• 2010

This study was conducted for searching the fauna, altitudinal distribution, and food patterns of the aquatic insects on Jeju island. The samples were collected from 102 freshwater wetlands during 2004 to 2008. The identified species were 100 belonged to 73 genera, 32 families, and 7 orders. One species of the genus Ephemeroptera, 23 of the Odonata, 1 of the Plecoptera, 23 of the Hemiptera, 47 of the Coleoptera, 3 of the Trichoptera, and 2 of the Diptera were identified in this study. The most widely distributed species was Sigara substriata, which was followed by Crocothemis servilia, Orthetrum albistylum, Gerris latiabdominis, and Anisops ogasawarensis. Sixteen species including Gynacantha japonica were very restrictedly distributed, which were sampled from only one site, respectively. The restrictedly distributed species (R) were classified into three altitudinal ranges, low (L), middle (M), and high (H). Ten species including Ranatra unicolor were RL type, only one species, Berosus japonicus, was RM, and 6 species including Nemoura KUb were RH. Narrowly distributed species (N) were 44 including Lethocerus deyrollei and intermediately distributed species (I) were 18 including Hesperocorixa distanti, and widely distributed species (W) were 21 including Nepa hoffmanni. According food uptake patterns, 75 species were carnivores, 18 herbivores, 5 omnivores, and 2 detritivores. Especially almost W were carnivores. From these results, we could concluded that the most aquatic insects species of Jeju island were characterized by their very limited altitudinal distribution range and carnivorous preference.

• Korean Journal of Plant Taxonomy
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• v.50 no.4
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• pp.377-384
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• 2020

Korean Sedum formosanum N. E. Br. (Ju-geog-nip-gaet-bi-reum in Korean) was first recorded in 1887, 133 years ago. Since then, the species has not been collected and its current state has remained unclear. However, these plants were collected in 2020 and the corresponding taxonomic entity and distribution status were revealed. It is known to be distributed only in the southern region of Japan, the northern islands of the Philippines, and in Taiwan, with Taiwan being the collection site of the type specimen. However, on the basis of the findings of the fourth national natural environment survey, it has recently been established that this plant also grows in the crevices of rocks along the seashores of the Korean islands of Hataedo Island and Sangtaedo Island, Sinan-gun, Jeollanam-do. S. formosanum inhabiting Korea is a large succulent biennial that can attain a height of up to 65 cm and differs from its congeneric species in having erect follicles during the fruiting period. Notably, among the Korean Sedum species, S. formosanum is most similar to S. tosaense, although it can be distinguished from this species with respect to its monomorphic leaves that have rounded apices, and it also bears separate flowering and sterile stems. In this paper, we present a description and photographs of the Korean S. formosanum, indicate the differences between this and related species, and provide a key to related taxa.

• The Journal of Engineering Geology
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• v.34 no.2
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• pp.163-171
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• 2024

Changes in the soil layer on Dokdo are important both academically and with regard to sustainable conservation and utilization of the islands. Continuous investigation and observation are necessary, as the soil layer is essential to the growth of plants and, therefore, the islands' ecosystem. Such work was carried out for about 8 years using soil erosion measuring bars, which are durable and facilitate simple monitoring of changes in the soil layer. Each bar comprised a rod measuring 30~50 cm long and 1.5 cm in diameter, and the use of stainless steel afforded resistance to corrosion caused by sea breezes. Six measuring bars were installed in the soil layers of each of two islands, Dongdo and Seodo, and measurements were taken one to three times a year from 2014 to 2021. The field measurements indicate that soil was deposited on Dongdo but eroded on Seodo during the observation period. As the measuring bars on Dongdo were located in the central and lower parts of the island, the observed changes in the soil layer resulted mainly from sedimentation of material eroded by weathering or soil runoff from the upper part of the island. In contrast, the measurement locations on Seodo were located in the upper and central parts of the island, where soil erosion and runoff diminished the soil layer at the observation points.