• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.3
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• pp.29-42
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• 2023

As the destruction of habitats due to recent development continues, there is also increasing interest in endangered species. Mankyua chejuense is a vulnerable species that is sensitive to changes in population and habitat, and it has recently been upgraded from Endangered Species II to Endangered Species I, requiring significant management efforts. So in this study, we analyzed the potential habitats of Mankyua chejuense using MaxEnt(Maximum Entropy) modeling. We developed three models: one that considered only environmental characteristics, one that considered artificial factors, and one that reflected the habitat of dominant tree species in the overstory. Based on previous studies, we incorporated environmental and human influence factors for the habitats of Mankyua chejuense into spatial information, and we also used the habitat distribution models of dominant tree species, including Ulmus parvifolia, Maclura tricuspidata, and Ligustrum obtusifolium, that have been previously identified as major overstory species of Mankyua chejuense. Our analysis revealed that rock exposure, elevation, slope, forest type, building density, and soil type were the main factors determining the potential habitat of Mankyua chejuense. Differences among the three models were observed in the edges of the habitats due to human influence factors, and results varied depending on the similarity of the habitats of Mankyua chejuense and the dominant tree species in the overstory. The potential habitats of Mankyua chejuense presented in this study include areas where the species could potentially inhabit in addition to existing habitats. Therefore, these results can be used for the conservation and management planning of Mankyua chejuense.

• Korean Journal of Plant Taxonomy
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• v.48 no.1
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• pp.1-8
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• 2018

Mankyua chejuense is the only member of the monotypic genus Mankyua (Ophioglossaceae) and is endemic to Jejudo Island, Korea. To determine the precise phylogenetic position of M. chejuense, two cpDNA regions of 42 accessions representing major members of lycophytes are obtained from GenBank and analyzed using three phylogenetic analyses (maximum parsimony, maximum likelihood, and Bayesian inference). In addition, the divergence time is estimated based on a relaxed molecular clock using four fossil calibration points. The phylogenetic position of Mankyua still appears to be uncertain, representing either the earliest diverged lineage within Ophioglossaceae or a sister to the clade containing Ophioglossum and Helminthostachys. The most recent common ancestor of Ophioglossaceae and its sister lineage, Psilotum, was estimated to be 256 Ma, while the earliest divergence of Mankyua was estimated to be 195 Ma in the early Jurassic.

• Korean Journal of Environmental Agriculture
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• v.35 no.2
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• pp.137-142
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• 2016

BACKGROUND: Identification of endophytic yeasts inhabiting the internal roots of the Mankyua chejuense tree requires techniques involving biotechnology. There is a need for a culture-based method to isolate and identify yeast strains associated with M. chejuense.METHODS AND RESULTS: We spread homogenized M. chejuense root samples onto glucose-peptone- yeast agar containing antibiotics, Triton X-100, and L-sorbose. A total of 152 yeast isolates were obtained and identified via phylogenetic analysis based on ITS gene sequencing. The results revealed that the root-associated yeast species included the genera Cyberlindnera (140 isolates), Candida (11 isolates), and Kluyveromyces (one isolate). Additionally, three yeast isolates showed high bioethanol production.CONCLUSION: We identified the specific yeast community associated with M. chejuense roots. These yeast isolates may have industrial applications as bioethanol producers. Our findings revealed that Cyberlindnera isolates included C. suaverolens and C. satumus, while Kluyveromyces isolates showed high bioethanol production.

• Korean Journal of Plant Resources
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• v.24 no.4
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• pp.395-403
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• 2011

This study was conducted to investigate the habitat positional environment and vegetation properties of Mankyua chejuense. The habitats were classified into two types depending on the depth of the habitat, the ratio of rock exposure, the dominant species and the surrounding vegetation, which affected the vegetation of the habitats. The habitats with a high ratio of rock exposure showed a distinctive geographical boundary to the adjacent region and most of them were composed of trees that grow in humid environment. On the contrary, in the soil-rich habitats, the depth was shallow, soil layer was well developed, and the trees were introduced from the adjacent areas. However, the dominant species in the herbaceous layer were aquatic plants, which indicated that the habitats had the properties of wetland. Therefore, it was found that thes habitats of Mankyua chejuense have the properties similar to those of marshland. For the preservation of Mankyua chejuense, it is very important to make the habitats maintain such properties of wetland.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.95-101
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• 2014

This study was conducted to analyze the pattern of growth and phenological characteristics of Mankyua chejuense B.-Y. Sun, M.H. Kim & C.H. Kim, which belong to the Ophioglossaceae family. M. chejuense asexually reproduced using rhizomes, and a clone of the species grew up to 52 cm based on root growth and new leaves was produced from rhizomes. The development of leaves were divided into four stages; leaf emergence-separation and growth of leaf-sporophyll maturation-senescence. Most leaves emerged in July and August with high temperatures and precipitation and most leaves reached full expansion during September-October and died during April-May next year. The life span of leave was 10 months, from July to April, and the start of leaf senescence varied depending on the habitat environment and this might result from micro environmental differences among the habitats.

• Journal of Ecology and Environment
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• v.37 no.2
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• pp.61-67
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• 2014

Mankyua chejuense is a native endangered plant distributed only in Gotzawal, a forested wetland, in Jeju Province, Korea. In order to determine the optimal environmental conditions for the growth and development of M. chejuense, we investigated the above- and below-ground growth responses and survival rate to various soil texture (sand and clay), water regimes (flooding and non-flooding), and $CO_2+T$ (ambient and elevated) conditions. All of the treatments had significant effects on aboveground growth parameters, while only the water regime and $CO_2+T$ treatments influenced belowground growth. The survival rate of M. chejuense was about twice higher under the sand, non-flooding and elevated $CO_2+T$ conditions than clay, flooding and ambient $CO_2+T$ conditions. These results indicate that M. chejuense grows in well-drained sandy soil conditions and elevated $CO_2$ concentration and temperature situations. Thus, there is a need to maintain M. chejuense under constant non-flooding soil conditions by implementing appropriate soil drainage strategies.

• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.350-359
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• 2010

The distribution of the Mankyua chejuense was restricted to the northeast region of Jeju Island. It grows in the isolated pit crater-like swamp areas of various extent and shape, where the height is lower compared to the adjacent areas, and the adjacent regions contained a evergreen broad-leaved forests, a shrubbery, and a grassland vegetation. It contained 147 taxa of 61 families, 112 genera and 147 species in the habitats. The life form of the flora showed that the habitat of M. chejuense is different from the surrounding others, in particular, the ratio of the Therophytes and the Hydrophytes appeared highly. Preservation of habitat conditions is very important for stable maintenance the flora, and the surrounding area including habitats has to be designated a protection area for habitat preservation.

• Journal of Wetlands Research
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• v.14 no.1
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• pp.35-45
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• 2012

In order to characterize the habitat trait and vegetation structure of M. chejuense(Ophioglssaceae), endangered plant in Korea, we set 12 permanent quadrats in Jocheon-Sunhyul Gotzawal Wetland Region of Jeju Island, and surveyed the temporal pools, vegetation structure and counted the population size of the endemic rare plant. M. chejuense distributed in the vernal pools with a variety of shape, area of 150-$400m^2$, depth of 0.4-2.0m and slope of 3-$10^{\circ}$, at altitude of 88-165m in lowland area in Gotjawal Wetland Region, Jeju Island. The soil has a thin layer and high water content all the seasons. The population appeared with a density range of 1-423/pool in the boundary area of the wetlands under higher tree coverages(80-100%) in the deciduous forest communities. Vegetation wsa classified into five plant communities such as Ulmus parvifolia community, Cudrania tricuspidata community, Rosa multiflora community, Ardisia japonica community, Ophiopogon japonicus community. These results means that M. chejuense potentially has a shortage to evergreen plant succession, litter accumulation and water drainage, thus it is need to sustainable wetland environmental condition in the deciduous forest community for its sounded conservation.

• Korean Journal of Plant Taxonomy
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• v.43 no.4
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• pp.274-284
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• 2013

This study presents a survey on the bryophytes in Dongbaek-dongsan located at Seonheul Gotjawal on the north-eastern face of Mt. Halla in Jeju Island, Korea. A total of 85 taxa belonging to the Bryophyta (22 families 44 genera 62 species), Marchantiophyta (12 families 16 genera 23 species) were found. Among them, 3 moss species, Diphyscium perminutum Takaki, Racomitrium japonicum Dozy & Molk., and Isopterygium minutirameum (M$\ddot{u}$. Hal.) A. Jaeger. were new additions to the bryophyte flora of Korea. The liverwort index was 27.0%. Predominant life-form was weft. The rates for the bryophytes dominating in mesic to hygric sites were higher than for the bryophytes mainly observed in xeric habitats. We considered that the composition and distribution of species are affected by the different environmental factors according to the evergreen broad-leaved forests, wetlands and exposed spaces. Moreover, the rocks were the substrate type that play a major role in providing the micro-habitats for bryophytes in this area. Particularly, the bryophytes of swamps in this area were very unique and various for its limited space and showed plant communities with mosaic spatial pattern, along with vascular plants. We suggest more detailed and comprehensive studies on the swamps where endemic fern Mankyua chejuense B. -Y. Sun, M. H. Kim & C. H. Kim inhabits to provide valuable information for the conservation and restoration of the species and habitats.

• Korean Journal of Plant Taxonomy
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• v.45 no.1
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• pp.96-107
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• 2015

This study presents a comprehensive account of the flora of hydrophytes and hygrophytes on Jeju Island. This approach aims to contribute to fundamental information about the conservation of plant diversity in wetlands. Field surveys were carried out from May of 2010 to September of 2014 in various types of wetlands on Jeju Island. A total of 189 taxa, including 52 families, 98 genera, 181 species, 6 varieties, 2 forma and 189 taxa, were found. Among them, 99 taxa (38 families, 60 genera, 96 species and 3 varieties) were hydrophytes and 90 taxa (23 families, 45 genera, 85 species, 3 varieties and 2 forma) were hygrophytes. In addition, Eleocharis${\times}$yezoensis H. Hara (Cyperaceae) was newly added to the flora of Korea. The protected wild plants designated by the Ministry of the Environment were 5 taxa, including Brasenia schreberi J. F. Gmel. and Dysophylla yatabeana Makino. The endangered species found included one Critically Endangered Species (i.e., Mankyua chejuense B.-Y. Sun, M. H. Kim & C. H. Kim), 5 Endangered Species (e.g., Lysimachia leucantha Miq.) and 7 Vulnerable Species (e.g., Tillaea aquatica L.). The floristic regional indicator plants found in this area were 44 taxa comprising 10 taxa of grade V, 7 taxa grade IV, 15 taxa of grade III, 5 taxa of grade II, and 7 taxa of grade I. The identified naturalized plants were 10 taxa; 8 families, 8 genera, 9 species and 1 variety. In the wetlands on Jeju Island, high plant species diversity was shown, and a number of rare plants and phytogeographically important plants were found. For these reasons, we consider that the wetlands on Jeju Island are very important areas from a botanical point of view. It is necessary to establish specific protection and maintenance policies in an effort to conserve these wetlands and species.