• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.575-581
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• 2022

Brown rats (Rattus norvegicusBerkenhout, 1769) were eradicated from Sasudo Island (33°55'13.04" N, 126°38'19.98" E), an uninhabited island designated as Natural Monument No. 333 and the largest breeding site for the streaked shearwater (Calonectris leucomelasTemminck, 1835) in South Korea. Twelve eradication studies were conducted from November 2015 to February 2021. The survey was conducted using a line census method that entailed slow wandering throughout the island and identifying starting and returning points. Capture traps were installed around traces of Rattus norvegicus,such as excrement and identified holes. As a result, 2 to 6 individuals were captured at each instance, except for the last time, when no individuals were captured. It is hypothesized that brown rats arrived at Sasudo Island via vessels arriving at the island for leisure and fishing. After the damage to streaked shearwater caused by brown rats was confirmed in 2006, entry to Sasudo Island was strictly prohibited through security measures, and marine clean-up programs that began in 2013 and continuous capturing since 2015 have been successful in eradicating brown rats. To maintain and manage the condition in Sasudo Island, preservation and management measures, such as strict visitor control, are necessary to prevent the inflow of new brown rats in the future.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.267-267
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• 2021

제주도는 화산섬의 지질특성상 강수의 지표침투성이 높아 지표수의 개발이용여건이 취약한 관계로 용수의 대부분을 지하수에 의존하고 있다. 따라서 지하수의 보전관리는 매우 중요한 사항이며 특히 지하수의 안정적인 이용을 위해서는 지하수 취수가 주변지역 지하수위에 미치는 영향 분석이 반드시 필요하다. 본 연구는 딥러닝 알고리즘인 Long Short-Term Memory(LSTM)를 활용하여 제주도 남동쪽 표선유역 중산간지역에 위치한 2개 지하수위 관측정을 대상으로 지하수 취수영향을 분석하였다. 입력자료로써 인근 2개 강우관측소의 일단위 강수량자료와 인근 6개 취수정의 지하수 취수량자료 및 연구대상 관측정의 지하수위 자료(2001. 2. 11. ~ 2019. 10. 31.)를 사용하였다. 지하수위 변동특성을 최대한 반영하기 위해 LSTM의 예측일수를 1일로 설정하였다. 보정 및 검증 기간을 사용하여 매개변수의 과적합을 방지하였으며, 테스트 기간을 사용하여 LSTM의 예측성능을 평가하였다. 평가지수로써 Nash-Sutcliffe Efficiency(NSE)와 평균제곱근오차(RMSE)를 사용하였다. 그리고 지하수 취수가 주변 지하수위 변동에 미치는 영향을 분석하기 위해 취수량을 최대취수량인 2,300 m³/일, 최대취수량의 2/3인 1,533 m³/일 및 0 m³/일로 설정하여 모의하였다. 모의결과, 2개 감시정의 보정, 검증 및 예측기간에 대한 NSE는 최대 0.999, 최소 0.976의 범위를 보였으며, RMSE는 최대 0.494 m, 최소 0.084 m를 보여 LSTM은 우수한 예측성능을 나타내었다. 이것은 LSTM이 지하수위 변동특성을 적절히 학습하였다는 것을 의미하며 따라서 추정된 매개변수를 활용하여 지하수 취수영향을 모의 및 분석하였다. 그 결과, 지하수위 하강량은 최대 0.38 m 였으며 이것은 대상지점에 대한 취수량은 지하수위 하강에 거의 영향을 주지 않는다는 것을 의미한다. 또한 취수량과 지하수위 하강량과의 관계는 한 개 관측정에 대해 선형적인 관계를 보인 반면 나머지 한 개 관측정에 대해서는 비선형적인 관계를 나타내는 것을 확인하였다. 따라서 LSTM 알고리즘을 활용하여 제주도 표선유역 중산간지역의 지하수위 변동특성을 분석할 수 있다.

• Journal of Mushroom
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• v.21 no.4
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• pp.228-240
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• 2023

To understand microorganism effects on wild mushroom fruiting bodies, we investigated the fungi in hyphosphere soil supporting wild mushroom species Cortinarius violaceus, Amanita hemibapha, Laccaria vinacelavellanea, and Amanita verna found in the Gotjawal area of Jeju Island. Fungal species identification based on morphological traits and molecular analysis of ITS, LSU rDNA, and β-tubulin gene sequences resulted in isolation and identification of eleven fungal species previously unrecorded in Korea. These newly-recorded species are: Arthrinium kogelbergensis, Kalmusia longisporum, Keithomyces carneum, Neopyrenochaeta cercidis, Penicillium ranomafanaense, Phomatodes nebulosa, Pyrenochaeta nobilis, Tolypocladium album, Talaromyces kendrickii, Talaromyces qii, and Umbelopsis gibberispora, and their morphological characteristics and phylogenetic positions are described.

• Journal of agricultural medicine and community health
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• v.36 no.1
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• pp.25-35
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• 2011

Objectives: This study aimed to compare depression and social support according to general characteristics and to investigate the influence of social support on depression. Methods: This study analyzed raw data from a project funded by Jeju Province. Data were collected through home visit interview with 750 households selected by using a randomized cluster sampling method. CES-D was used to measure depression, and the Medical Outcomes Study Social Support Survey was used to measure social support. The data of 1,155 subjects were analyzed using t-test, ANOVA, and regression. Results: The mean was 11.35 for depression and 75.53 for social support. Women showed a higher depression score and a lower social support score than men did. Older people; the divorced or the bereaved; and those in groups comprising people with lower education, lower social class, poor health, or high stress presented higher depression and lower social support. The result of stepwise regression showed that social support was one of the predictive variables of depression, and 22% of variance was explained by social support in this study. Conclusions: Social support was a powerful predictive variable of depression, and it was suggested that to prevent and manage depression, strategies that enhance social support should be developed and evaluated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7761-7772
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• 2015

This study describes the spatio-temporal distributions in phytoplankton community such as species composition, standing crops and dominant species from April to November 2008 in the Jeju Marine Ranching Area (JMRA). A total of 106 species of phytoplankton belonging to 63 genera was identified. In particular, diatoms and dinoflagellates were occupied more than 61% and 35% of total species, respectively. The annual dominant species were Skeletonema costatum-like species(ls) in April, Torodinium teredo, Cylindrotheca closterium, Scrippsiella trochoidea in June, S. costatum - ls, Thalassionema nitzschioides, Pseudo-nitzschia pungens, Ebria tripartita in September and Corethron pennatum, Dictyocha fibura, Neoceratium teres in November. Phytoplankton cell density ranged between $0.6cells{\cdot}mL^{-1}$ in June and $64.0cells{\cdot}mL^{-1}$ in April. It fluctuated with an annual mean of $11.7cells{\cdot}mL^{-1}$ between the lowest value of $0.9cells{\cdot}mL^{-1}$ in November and the highest value of $37.0cells{\cdot}mL^{-1}$ by S. costatum -ls in April. Diversity index in September was higher than diatom blooming seasons in April. According to the phytoplankton community structure, the biological oceanographic characteristics of the JMRA was characterized by nanoplankton during a year. That is, primary production is deemed to have a higher possibility of being adjusted by a reproduction by material cycle in the ecosystems than nutrients supply from the lands.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.110-113
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• 2004

제주도내에 개발ㆍ이용 중인 사설 농업용 44개 관정을 대상으로 2002년 11월부터 2003년 11월까지 1년간 지하수 이용량 모니터링 조사를 실시하였다. 재배작물 유형별 지하수 이용특성을 평가한 결과, 밭작물은 대체로 9월에서 11월 초순까지 집중적으로 지하수를 이용하고 있으며, 시설하우스의 경우에는 2월에서부터 10월말까지 비교적 지속적으로 지하수를 이용하고 있는 것으로 분석되었으나, 노지 감귤원은 가뭄이 아닌 경우에는 농약살포시 매우 소량의 지하수를 이용하고 있으며 이용시기도 매우 불규칙한 것으로 조사되었다. 평균 총 가동 일수는 시설하우스 및 밭작물에 혼용으로 사용하고 있는 지하수 관정의 128일로 최대치를 나타내고 있으며, 연간 지하수 총 이용량의 경우도 관정 가동 일수와 같은 경향을 나타내고 있다. 단위 면적(ha) 당 지하수 일 평균 이용량은 시설하우스가 74m$^3$/일으로 가장 많았고 밭작물이 50m$^3$/일로 조사되었다. 원격검침 시스템에 의해 얻어진 모니터링 테이터로부터 산정된 양수량과 계량기 검침에 의한 양수량과의 관계를 비교 분석한 결과, 상관계수가 $R^2$ =0.997을 나타내 수중모터펌프 가동시간 모니터링에 의한 양수량 산정방법이 매우 유효함이 입증되었다.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.582-591
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• 2022

This study was conducted to eliminate Myocastor coypusMolina, 1782 (Nutria) from Jeju Special Self-Governing Province, South Korea. Habitat identification and eradication were carried out from September to November 2013, and a survey was carried out until June 2022 to check whether the eradication was successful. The habitat was identified with unmanned cameras, interviews, and literature surveys, and the capture was performed using the trapping method with food to attract nutria to the habitat area. The study area for the follow-up survey, which was set relatively wide considering nutria's home range, included wetlands and rivers within 4.0 km² of the habitat area (eradication area). As a result, nutria's habitat was confirmed only at Songdang Ranch, Songdang-ri, of Jeju Island, with traces of habitat (footprints, excrement, and burrows) confirmed in waterways and ponds within the pasture. Eight individuals were captured, including four females, three males, and one individual in too advanced a state of decay to identify the sex. The follow-up survey thoroughly investigated the habitat and its surroundings, focusing on three areas with permanent water, Seongeup Reservoir, Cheonmi Creek, and Molsuni Pond, but no signs of habitat were identified. Therefore, it is determined that nutria inhabiting Jeju Island has been completely eradicated. It is believed that the successful eradication of nutria in the Jeju Special Autonomous Region was possible due to a synergy between 1) the eradication of nutria at the beginning of the settlement phase through rapid capture after confirming the nutria habitat and 2) the delayed expansion period because of rare presence of wetlands, where water is constantly stagnant, on Jeju Island. These results imply that quickly identifying the ecological characteristics of the species and preventing disturbances before they or at the beginning of the ecological disturbance through control and eradication at the initial stage of settlement before the expansion stage is an effective measure to cope with the influx of alien species.

• Korean journal of applied entomology
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• v.18 no.4 s.41
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• pp.169-175
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• 1979

A study on the plant parasitic nematodes (Tylenchida) in JeJu province has been undertaken to know the kinds and distribution of the nemic fauna. The 42 samples taken from 28 kinds of host plants were used. 1. The 22 species belonging to 16 genera in 10 families were discovered in this study and among them Meloidogyne was the most common and widely distributed genus, composing $25\%$, followed by Helicotylenchus $15\%$, Criconemoides $14\%$, Tylenchus $10\%$, Pratylenchus $6\%$, Neolobocriconema $6\%$, Aphelenchus $6\%$, Aphelenchoides $6\%$, Hirshmaniella $3\%$, Heterodera $3\%$ Nothotylenchus $1\%$, Tylenchorhynchus $1\%$, Merlinius $1\%$, Rotylenchus $1\%$ Discocriconemella $1\%$ and Hemicriconemoides $1\%$. 2. The ll species belonging to 10 genera in 7 families such as Nothotylenchus acris, Tylenchorhynchus dubius, Merlinius nothus Pratylenchus minyus, Pratylenchus thornei, Hirshmaniella imamuri, Rotylenchus robustus, Helicotylenchus erythrinae, Meloidogyne arenaria, Discocriconemella hengsungica and Aphelenchoides besseyi were newly discovered species in JuJu province.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.255-262
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• 1982

The data of 37 oceanographic stations in the coastal sea of Jeju island are compiled in terms of temperature, salinity, dissolved oxygen, silicate, nitrate and phosphate to analyge the chelnical characteristics in this region. This work was carried out during June, 1951. The concentrations of nutrients in the layer more than 50 m are generally 0.5-3 times larger than the surface layer. Each constituents in this layer are as follows: temperature ranged 11.8 to $15.4^{\circ}C$ and salinity, 33.8 to $34.8\%_{\circ}$; and also dissolved oxygen and slicate are 5.2 to 5.6ml/l and 5.6 to $9.0{\mu}g-at/l$, respectively. And nitrate and phosphate ranged 1.0 to $6.0{\mu}g-at/l$ and 0.1 to $0.5{\mu}g-at/l$, respectively. The coastal sea of Jeju island is divided into two parts in chemical view point : one is the southeastern sea of Jeju island under the influence of the Tsushima Current, md the other is the northeastern sea of Jejo island under the influence of the Yellow Sea Bottom Cold Water and the south coastal water of Korea. The north-western sea of Jeju island had relatively a cold (about $13^{\circ}C$) and low saline water (about $34\%_{\circ}$), and dissolved oxygen was higher than in the neibouring waters. It seems that in the southern area between Moseulpo and Seogwipo of Jeju island, two different Ivater masses are complicately intermixed and a tidal front is formed.

• 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.