• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.1
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• pp.61-68
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• 2011

The "ship's routeing" system was adopted by IMO and has been operated on the major sea routes of all over the world for the prevention of marine casualty and the improvement of marine traffic flow. Thereupon, also in Korea, the "Hong-do" and "Bogil-do" sea routes on southern coast were designated to mandatory sea area by traffic separation scheme(TSS) in 2003, and the "Geomun-do" sea route on southern coast was designated in 2005. But there were few or no studies on the effect of designated traffic separation scheme in Korea. For this reason, in this paper, we evaluated the contribution of traffic separation scheme to the prevention of marine casualty and the improvement of marine traffic flow after designation of domestic traffic separation scheme using data of the marine casualties and ship's tracks from AIS information. The results of evaluation showed that on the contrary, the cases of marine casualties were increased on some sea routes and regular traffic flows were disturbed by some vessels after designation of traffic separation scheme. For the safer and better sea routes, alternative ideas such as reposition of ship's routing on "Hong-do" and "Bogil-do" sea areas were suggested.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.3
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• pp.82-91
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• 2007

Rural areas dominate country landscape, where the population is rich in traditional and natural heritage. Dangsan forests and Rural community forests (RCF) have been maintained by local residents for hundreds of years. However, many of these forests have been disturbed, and only small amount of Dangsan forests and the RCF remain due to the efforts of local residents. Recently, the remnants of Dangsan forests and RCF have been regarded as living traditional landscapes representing the cultural and rural background of Korea. But the value of Dangsan forests and the RCFs has not been recognized by many. This study aims to understand the characteristics and management status of Dangsan forests in Sungnam-ri, Wonju. Sungnam-ri has four villages, each of which is bordered by a Dangsan forest at the riparian buffer. Sungnam-ri has been selsected as a site for a rural village development project by the Ministry of Agriculture & Forestry of Korea. Sunghwanglim (the Upper Dangsan forest) is designated as Natural Monument No.93 and entrance is limited in this area. The size of Sunghwanglim is $21,133m^2$, and the major tree species are Kalopanax pictus (Dangsan tree, Divine tree), Pinus densiflora, Abies holophylla, Acer triflorum, Ulmus davidiana, Fraxinus rhynchophylla and Quercus serrata. In total, 124 trees with more than 40 cm in DBH are at this site. As for cultural activities, the Dangsan festival is held on April 8th and September 9th of the lunar calendar at shrines in the forests. Although other Dangsan forests are smaller than Sunghwanglim, they also have similar cultural activities. The landscape of the Dangsan forests have been managed for several hundred years by the local people, and they intend to continue maintaining the Dangsan forests for the purpose of festivals and other cultural activities. The findings in this study suggest that Dangsan forests have the potential for the development of rural villages and for the improvement of cultural and natural landscapes in Korea.

• Journal of the Mineralogical Society of Korea
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• v.25 no.3
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• pp.155-162
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• 2012

We observed characteristic oxidation and dissolution phenomena induced by dissolved oxygen for mackinawite that is produced via sulfate-reducing bacteria (SRB) living in anaerobic environments such as soils and groundwater. We tried to recognize the role of the sulfide minerals that usually coexist with some stabilized radionuclides (e.g., reduced uranium), which can be reoxidized and redissolved by an oxygen-rich groundwater invaded into a contaminated area. The mackinawite produced by 'Desulfovibrio desulfuricans', a sulfate-reducing bacterium, was conducted to be dissolved for 2 weeks by some oxidants such as 'hydrogen peroxide' and 'sodium nitrite'. Although mineralogical oxidation and dissolution characteristics were different from each other according to the oxidants, the initially oxidized solution was early stabilized through the oxygen consumption by ${\mu}m$-sized sulfide particles and the resultant increase of sulfate in solution. From these results, we can anticipate that the large amount of sulfide minerals generated by SRB can not only repress the anoxic environment to be disturbed by the consumption of oxygen in groundwater, but also contribute to stabilize the reduced/precipitated radionuclides as a buffer material for a long time.

• Journal of Environmental Impact Assessment
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• v.23 no.4
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• pp.271-284
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• 2014

The objectives of this research were to analyse the microhabitat of Cobitis choii which is designated as an endangered fish species (I) and national monument species in Korea (No. 454), and provide valuable information of suitable replacement habitat in the future for a conservation of the population with rapid decreases by environmental pollution. Sampling and microhabitat analysis in three streams such as Baekgok, Yugu and Gap Stream, known as one of the least habitats in Korea showed that the mean number of Cobitis choii observed was 2.6. This result indicated that the richness was too low, so the species conservation was very urgent. Optimal physical microhabitat of the population was determined as environmental conditions with > 60% sand with 1 mm particle size, optimal water depth of 20 - 60 cm in the habitats, and the optimal current velocity of < 0.4 m/s. Under the circumstances of the microhabitat, optimal water volume (discharge) was 0 - 2 m3/s in the each sectional analysis and this reach was mainly composed of the stream section with intermittant slow runs and pools. These microhabitats were largely disturbed by physical modifications of habitat and chemical pollutions due to direct influences of nutrient-rich water inputs from the urban area and intensive agricultural pollutants. For these reasons, optimal habitat replacement are required in the future for the conservation of the species.

• Wind and Structures
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• v.7 no.5
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• pp.317-332
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• 2004

Wind tunnel experiments were conducted under highly turbulent and disturbed flow conditions over a solid/perforated plate with a long splitter plate in its plane of symmetry. The effect of varied level of perforation of the normal plate on fluctuating velocities and fluctuating pressures measured across and along the separation bubble was studied. The different perforation levels of the normal plate; that is 0%, 10%, 20%, 30%, 40% and 50% are studied. The Reynolds number based on step height was varied from $4{\times}10^3$ to $1.2{\times}10^4$. The shape and size of the bubble vary with different perforation level of the normal plate that is to say the bubble is reduced both in height and length up to 30% perforation level. For higher perforation of the normal plate, bubble is completely swept out. The peak turbulence value occurs around 0.7 to 0.8 times the reattachment length. The turbulence intensity values are highest for the case of solid normal plate (bleed air is absent) and are lowest for the case of 50% perforation of the normal plate (bleed air is maximum in the present study). From the analysis of data it is observed that $\sqrt{\overline{u^{{\prime}2}}}/(\sqrt{\overline{u^{{\prime}2}}})_{max}$, (the ratio of RMS velocity fluctuation to maximum RMS velocity fluctuation), is uniquely related with dimensionless distance y/Y', (the ratio of distance normal to splitter plate to the distance where RMS velocity fluctuation is half its maximum value) for all the perforated normal plates. It is interesting to note that for 50% perforation of the normal plate, the RMS pressure fluctuation in the flow field gets reduced to around 60% as compared to that for solid normal plate. Analysis of the results show that the ratio [$C^{\prime}_p$ max/$-C_{pb}(1-{\eta})$], where $C^{\prime}_p$ max is the maximum coefficient of fluctuating pressure, $C_{pb}$ is the coefficient of base pressure and ${\eta}$ is the perforation level (ratio of open to total area), for surface RMS pressure fluctuation levels seems to be constant and has value of about 0.22. Similar analysis show that the ratio $[C^{\prime}_p$ max/$-C_{pb}(1-{\eta})]$ for flow field RMS pressure fluctuation levels seems to be constant and has a value of about 0.32.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.26-26
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• 2019

DMZ 일원은 정전협정으로 비무장지대(DMZ: Demilitarized Zone)가 설정된 이래 민간인의 출입이 엄격히 금지된 채로 외부의 간섭에서 벗어난 독보적 공간으로 보전되어 오고 있다. 하지만 일부 지역은 자연재해 및 군사적 목적으로 훼손되어 생태적으로 교란된 지역이 발생하여 생태적 건강성이 저하되고 있다. 무엇보다 군사분계선 남쪽 2km에 설치된 남방한계선은 군사적 목적에 따라 시계확보를 위해 불모지작전을 수행하여 생태적 교란 및 토양침식에 의해 생태계가 열악한 실정이다. DMZ 내 생태교란지 식물복원 연구는 DMZ내 생태교란지를 하나의 특수한 생태계로 간주하여, 향후 DMZ내 생태교란지에 특화된 식생복원 체계를 마련하는데 그 목적이 있다. 이에 본 연구에서는 DMZ 155마일(248km)에 대해서 위성영상분석을 수행하여 생태교란지 유형화분류 연구를 수행하여 7개 유형(저지대초지, 서부저지대산지, 저습지 및 수공간 지역 등)으로 분류하였다. 또한 DMZ 생태교란지에 적합한 식물종 선정을 위하여 DMZ 전역을 대상으로 식물상 조사를 실시하여, 분포가 확인된 종을 대상으로 도입 가능종의 검토, 종자 수집 및 채종원 조성을 실시하였다. 추후 DMZ 생태교란지 식물복원에 적합한 공법연구를 수행하고자 한다. 시계확보를 위해 수행되는 불모지 작전에 적합한 종의 선정, 선정된 종을 대상으로 유사환경 조성에 따른 공법 적용, 적용된 공법에 따른 관리 방안 연구를 함께 수행하고자 한다. 본 연구를 통해 DMZ 일원에 특화된 공법개발이 이루어진다면 불모지 작전 및 관리 최소화가 이루어지고, 무엇보다 우리나라 종자 및 야생화 산업의 활성화와 현재 파편화 되어 있는 생태축이 하나의 축으로 연결 될 것이라고 기대해 본다.

• Journal of Ecology and Environment
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• v.45 no.4
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• pp.277-286
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• 2021

Background: As trade increases, the influx of various alien species and their spread to new regions are prevalent and no longer a special problem. Anthropogenic activities and climate changes have made the distribution of alien species out of their native range common. As a result, alien species can be easily found anywhere, and they have nothing but only a few differences in intensity. The prevalent distribution of alien species adversely affects the ecosystem, and a strategic management plan must be established to control them effectively. To this end, hot spots and cold spots were analyzed according to the degree of distribution of invasive alien plants, and major environmental factors related to hot spots were found. We analyzed the 10,287 distribution points of 126 species of alien plants collected through the national survey of alien species by the hierarchical model of species communities (HMSC) framework. Results: The explanatory and fourfold cross-validation predictive power of the model were 0.91 and 0.75 as AUC values, respectively. The hot spots of invasive plants were found in the Seoul metropolitan area, Daegu metropolitan city, Chungcheongbuk-do Province, southwest shore, and Jeju island. Generally, the hot spots were found where the higher maximum temperature of summer, precipitation of winter, and road density are observed, but temperature seasonality, annual temperature range, precipitation of the summer, and distance to river and sea were negatively related to the hot spots. According to the model, the functional traits accounted for 55% of the variance explained by the environmental factors. The species with higher specific leaf areas were more found where temperature seasonality was low. Taller species preferred the bigger annual temperature range. The heavier seed mass was only preferred when the max temperature of summer exceeded 29 ℃. Conclusions: In this study, hot spots were places where 2.1 times more alien plants were distributed on average than non-hot spots (33.5 vs 15.7 species). The hot spots of invasive plants were expected to appear in less stressful climate conditions, such as low fluctuation of temperature and precipitation. Also, the disturbance by anthropogenic factors or water flow had positive influences on the hot spots. These results were consistent with the previous reports about the ruderal or competitive strategies of invasive plants instead of the stress-tolerant strategy. The functional traits are closely related to the ecological strategies of plants by shaping the response of species to various environmental filters, and our result confirmed this. Therefore, in order to effectively control alien plants, it is judged that the occurrence of disturbed sites in which alien plants can grow in large quantities is minimized, and the river management of waterfronts is required.

• Korean Journal of Environmental Biology
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• v.42 no.1
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• pp.28-45
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• 2024

This study was conducted to investigate the flora of Sonjukdo Island(Yeosu-si), Korea. From results of four field surveys from April 2023 to October 2023, we identified 483 total taxa, representing 440 species, seven subspecies, 35 varieties, and one hybrid. They were placed in 322 genera and 109 families, including 249 taxa newly recorded in this study. Among them, four taxa were endemic to Korea, four taxa were IUCN red list plants, and 22 taxa were climate sensitive indicator plants. Floristic target plants amounted to 99 taxa, including two taxa of grade IV, 41 taxa of grade III, 10 taxa of grade II, and 46 taxa of grade I. A total of 54 taxa of alien plants were identified, with a Naturalized Index of 11.2% and an Urbanization Index of 13.8%. Three plants disturbed the ecosystem. The flora of this surveyed area belongs to the south-coast province among floral provinces of the Korean Peninsula. Our results provide basic data on vascular plants flora, plant species diversity, and distributional changes.

• Korean Journal of Environmental Biology
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• v.42 no.1
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• pp.95-126
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• 2024

In this study, we investigated the vertical distribution and vascular plants on Joryeongsan Mountain in Baekdudaegan, Korea. The results of four field surveys from April to September 2023 identified a total of 552 taxa, representing 491 species, ten subspecies, 43 varieties, six forms, and two hybrids in 314 genera and 101 families. The elevational distribution ranges of 360 taxa of vascular plants were also identified. Among them, 19 taxa were endemic to Korea, and two taxa were rare plants. The floristic target plants amounted to 100 taxa, specifically two taxa of grade V, seven taxa of grade IV, 25 taxa of grade III, 33 taxa of grade II, and 33 taxa of grade I. Seventy-eight taxa were northern lineage plants. In all, 29 taxa of alien plants were recorded in the investigated area, with a naturalized index of 5.3% and an urbanization index of 7.4%. Two plants disturbed the ecosystem. Species richness along the elevation showed a reversed double-hump shape with peaks at low, mid, and high elevations. The results of a cluster analysis showed a high degree of similarity between adjacent elevation sections, except in lowlands. Detrended Correspondence Analysis ordination also supported distinct groups by elevation. Warmth index values ranged from 62.1℃·month to 92.9℃·month on Joryeongsan Mountain. Our results provide primary data on vascular plants and valuable information on the current distribution ranges of plant species on Joryeongsan Mountain. These data could serve as a baseline for comparing species shifts at elevations under future climate changes.

• Journal of the Korean Association of Geographic Information Studies
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• v.16 no.4
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• pp.79-90
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• 2013

The altitude range of habitats in which Fairy Pitta inhabited in 1960s is different from the present in Jeju Island. We studied on the habitat environment to understand the causes of difference through the comparison of satellite image data(Landsat) between 1975 and 2002, the literature review in relation to habitats, vegetations, and forest landscapes. The area of below 600m asl.(above sea level) where is mainly Fairy Pitta inhabited at the present with a lot of forests, was massive pasture with small isolated forests nearby valley. The forests were broad-leaved evergreen forests, and second forests with poor condition in the size and forest structure. The forests around 700m asl. were also second forests with approximately 3m height trees. The forests from 800m to 1300m asl. were also disturbed by mushroom cultivation by local people. The authors believe that Fairy Pitta could not inhabited in the area above 1300m because of the poor forest conditions in the size and structure in which consist of Ilex crenata, Rhododendron mucronulatum var. ciliatum and coppice forests. Therefore it might be possible that the best forests for the Fairy Pitta habitat were located in the area of 1,000m to 1,300m above sea level in 1960s. Compared to present habitats, forests at 100m up to 800m above sea level, the authors believe that the size of habitats were smaller with less population of Fairy Pitta. Since 1960s the forest landscape of Jeju Island has been improved successfully, and because of that the population of Fairy Pitta also has been increased. To protect the Fairy Pitta and habitats in Jeju Island, it is suggested that sustainable forest management focusing on the species composition and stand structure maintain or enhance the biodiversity.