• Ocean and Polar Research
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• 제29권3호
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• pp.205-216
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• 2007

The purpose of this study was to investigate effects of large scale marine sand mining on the marine ecological community. For the study, four stations along the coast were selected and monitored in 1998 and 2001 at mining areas and non-mining areas about the Gyeonggi Bay. The result revealed that in 1998, 9 species of fishes, 16 species of crustaceans, and 6 species of mollusks were collected where as in 2001, 11 species of fishes, 5 species of crustaceans, and 2 species of mollusks were collected, uncovering the fact that fishes have diversified while crustaceans and mollusks have reduced on a grand scale. Also, there were two key characteristics regarding the changes of biological communities in mining and nonmining areas. The first was the dwindling of crustaceans inhabiting the sand area. This outcome may be accounted for by the facts that physical removal of seabed sediments and re-sediment due to expansion of floating particles cause direct influence on the ocean floor ecosystem and have continuous effect on the communities of crustaceans which feed on them. Secondly, the newly arrived species and their population during spring and summer seasons have increased in the non-mining areas and have decreased in the mining area. It can be concluded that highly nomadic fish species migrate toward areas with less disturbance or destruction of ecosystem from marine sand mining, and consequently, the communities of fishes change in the sea area. Setting aside the characteristics of the investigated sea areas where the arriving conditions of species vary by seasons, the clear differences of population of organisms in those areas are due to environmental alterations owing to the marine sand mining ; if those large-scale marine sand mining activities continue in the Gyeonggi Bay, their effects on biological communities in the areas will only grow.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 춘계학술대회
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• pp.464-465
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• 2018

국내의 대표적인 생태계 교란 외래어종인 배스와 블루길은 국내 토종 어류 개체군 감소에 가장 중요한 요인으로 보고되고 있다. 그러므로 이러한 외래어종 퇴치를 위한 시스템개발 및 현장 적용기술이 필요한 실정이다. 본 연구는 이러한 시스템개발에 앞서 물고기 인식을 위한 전체적인 시스템을 설계하고자 한다. 최근 들어 물체의 인식, 분류 그리고 학습에 이르는 일련의 과정들을 딥러닝(deep learning) 중 하나인 CNN(convolutional Neural Network)이 매우 뛰어난 성능을 나타내고 있다. 그러나 물체의 인식과 분류작업에 사용된 CNN의 데이터들은 특징들이 확연한 다른 물체의 인식과 분류에 주로 적용되었다. 본 연구는 비슷한 특징들을 갖는 물고기 개체들의 분류에 CNN을 적용하는 시스템을 설계하고자 한다.

• 한국환경복원기술학회지
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• 제12권1호
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• pp.82-91
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• 2009

Research was initiated to investigate vegetation characteristics of native ('Pureundle' and 'Sewon') and introduced ('Brilliant' and 'Midnight') Kentucky bluegrass (KB, Poa pratensis L.) varieties by soil-seed applying system on a cut-slope in May 17, 2008. There were no statistic differences observed in soil hardness and soil moisture content while significant differences were observed in surface coverage rate, height and disease occurrence in native and introduced KB varieties. The introduced 'Brilliant' KB was highest in the surface coverage rate from the early period of seeding to August 11, 2008. The surface coverage rate of introduced varieties were high when compared to native varieties in their early growth stage. But native varieties reached to equal surface coverage rate with the introduced varieties when three months after seeding. The height of 'Pureundle' and 'Brilliant' KBs were high compared with Midnight and Sewon KBs. 'Pureundle' and 'Brilliant' KBs were damaged by disease whereas there were no disease occurrence in 'Midnight' and 'Sewon' KBs. Probably, the disease occurrence was close related with the height of KBs not with native and introduced KB varieties. These results indicate that the growth of KB on a cut-slope are statistically affected by varieties in early growth stage of this experiment but reach equal rate between native and introduced KB varieties in three months after seeding. This growth characteristics implies the huge potential of native KB varieties seeding for cut-slope vegetation. Considering that native KB varieties are adapted to a environment and have no risk of causing disturbance to the ecosystem compared to the introduced KB varieties, the use of them as native varieties for a cut-slope vegetation can be increased.

• 한국약용작물학회지
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• 제25권3호
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• pp.139-145
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• 2017

Background: Invasion of these invasive plants in the ecosystem threatens the habitat of endemic species, reduces biodiversity, and causes a disturbance in the ecological system. Hypochaeris radicata L. (Asteraceae), the most invasive plant in Korea, particularly in Jeju Island, invades farmlands, and autochthonous forests, resulting in the establishment of monocultures and modification of the ecosystem structure. Methods and Results: In this study was, we evaluated the biological activity of 70% ethanolic extracts from different parts of Hypochaeris radicata L. The biological activities of 70% ethanolic extracts of different parts, such as flower, leaf, stem, and root, of H. radicata were investigated. The total polyphenol content was highest in flower extracts ($50.82{\pm}3.16mg{\cdot}QE/g$). In addition, the highest flavonoid content was observed in flower extract ($15.19{\pm}2.03mg{\cdot}QE/g$). The flower extract of H. radicata exhibited stronger DPPH radical-scavenging activities, ABTS radical scavenging activities, and reducing power than the other parts. The flower extract of H. radicata was observed to have the highest tyrosinase and ${\alpha}-glucosidase$ inhibitory activities. Conclusions: The flower extracts of H. radicata exhibited remarkable antioxidant activity as well as tyrosinase and ${\alpha}-glucosidase$ inhibitory effects. These activities might be related to the phenolic compounds present in the H. radicata flower extract.

• Journal of Ecology and Environment
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• 제43권4호
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• pp.364-375
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• 2019

Background: Ecologists continue to investigate the factors that potentially affect the pattern and magnitude of tree damage during catastrophic windstorms in forests. However, there still is a paucity of research on which trees are more vulnerable to direct damage by winds rather than being knocked down by the fall of another tree. We evaluated this question in a mixed hardwood-softwood forest within the Big Thicket National Preserve (BTNP) of southeast Texas, USA, which was substantially impacted by Hurricane Rita in September 2005. Results: We showed that multiple factors, including tree height, shade-tolerance, height-to-diameter ratio, and neighborhood density (i.e., pre-Rita stem distribution) significantly explained the susceptibility of trees to direct storm damage. We also found that no single factor had pervasive importance over the others and, instead, that all factors were tightly intertwined in a complex way, such that they often complemented each other, and that they contributed simultaneously to the overall susceptibility to and patterns of windstorm damage in the BTNP. Conclusions: Directly damaged trees greatly influence the forest by causing secondary damage to other trees. We propose that directly and indirectly damaged (or susceptible) trees should be considered separately when assessing or predicting the impact of windstorms on a forest ecosystem; to better predict the pathways of community structure reorganization and guide forest management and conservation practices. Forest managers are recommended to adopt a holistic view that considers and combines various components of the forest ecosystem when establishing strategies for mitigating the impact of catastrophic winds.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1998년도 21세기 한반도 농업전망과 대책(한국작물학회.한국육종학회 공동주관 심포지움 회보)
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• pp.313-335
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• 1998

If the atmospheric concentrations of greenhouse gases double, the annual temperature increase in mean surface temperature relative to 1990 will be about 2.0 to $2.5^{\circ}C$ and the annual precipitation increase about $15{\%}$ by 2100 in Korea. When the temperature rises $2^{\circ}C$, the annual temperature will be $13^{\circ}C,\;15^{\circ}C,\;and\;16^{\circ}C$ in Western Central, Yeongnam Basin, and Southern Coastal respectively. Consequently the crop period could be prolonged $10{\~}29$ days. In the case of gradual global warming, annual crops could be adapted to the changed environment by breeding, and the perennial crops should be shifted to ether area. If global warming happens suddenly over the threshold of atmospheric greenhouse gases concentration, then we shall have disturbance of ecosystem. When $2^{\circ}C$ higher than present, the optimum flowering date of rice plant delayed about 10 days, so it may not possible to adopt the fate with present japonica rices, therefore, the recommended characteristics of rice varieties are longer basic vegetative period, more late maturing and higher ripening temperature. Barley and wheat crops could be shifted to northern coastal areas and apple production areas should be shifted to those areas under $13.5^{\circ}C$ in annual mean temperature at global warming. Ideotypes of crops under climate changes should have such ecological characteristics that are indispensable to accomplish the sustainable agriculture under increased $CO_{2}$ and temperature condition as the diversification of genetic resources from yield-oriented to biomass-oriented characteristics with the higher potentials of $CO_{2}$ absorption and Primary production. In addition, a heat-tolerance, a pest resistance, an environmental adaptability and a production stability should be also incorporated collectively into our integrated agroecosystem.

• Journal of Ecology and Environment
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• 제45권4호
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• pp.237-254
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• 2021

Background: Some of the introduced alien species introduced settle, multiply, and spread to become invasive alien species (IAS) that threaten biodiversity. To prevent this, Korea and other countries legally designate and manage alien species that pose a risk to the environment. Moreover, 2160 alien species have been introduced in South Korea, of which 1826 animals and 334 plants are designated. The inflow of IAS can have negative effects such as ecosystem disturbance, habitat destruction, economic damage, and health damage to humans. To prevent damage caused by the inflow of IAS in advance, species that could potentially pose a risk to the environment if introduced in South Korea were designated as alert alien species (AAS). Results: The designation criteria were in accordance with the "Act on the Conservation and Use of Biological Diversity" and the "Regulations on the Ecological Risk Assessment of AAS and IAS" by the National Institute of Ecology. The analysis result of risk and damage cases indicated that mammals affect predation, competition, human economic activity, virus infection, and parasite infection. Birds have been demonstrated to affect predation, competition, human economic activity, and health. It was indicated that plants intrude on the ecosystem by competing with native species with their high-population density and capacity to multiply and cause allergic inducement. Interestingly, 300 species, including 25 mammals, 7 birds, 84 fishes, 28 amphibians, 22 reptiles, 1 insect, 32 spiders, 1 mollusk, 1 arthropod, and 99 plants, are included in the list of AAS. Conclusions: AAS designation plays a role in preventing the reduction of biodiversity by IAS in South Korea and preserving native species. Moreover, it is determined to provide considerable economic benefits by preventing socio-economic losses and ecological damage.

• 한국물환경학회지
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• 제39권4호
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• pp.329-342
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• 2023

Turbid water and suspended sediment (SS) load are having negative consequences such as water quality degradation and ecological damage, thus necessitating the establishment of management guidelines to reduce their impact. The present work investigates the spatio-temporal distribution of fish species and the effects of turbid water from 2011-2016 in the upper reaches of Soyang-Dam. The family Cyprinidae is the largest population in the study area, among which Zacco platypus and Zacco koreanus are the dominant species. The diversity of species is relatively abundant in the upper watershed, while the seasonal effect on the population distribution remains unclear. Using two main common components of the empirical orthogonal function (EOF) analysis, the distribution characteristics of 27 species at five survey sites are revealed. Zacco koreanus is found to be predominant at the upstream A-Naerincheon, while Zacco platypus and Rhinogobius brunneus are found to be predominant at the upstream B-Bukcheon. Disturbance of an aquatic ecosystem has a relatively greater impact in the downstream, as-compared to the upper area-the high proportion of forest area is decreased whereas that of agricultural and urbanized areas is increased. The patterns of representative species are changed according to the mid- to long-term effects of turbid water and SS. Accordingly, the significant correlation between the SS load and fish distribution EOF analysis indicates that it should be considered as a potential alternative that can overcome the limitations of impact assessment on turbid water to the Fish Assessment Index (FAI). A comprehensive study examining the long-term effects of SS load to the fish ecosystems with a systematic statistical analysis of sufficiently accumulated data at the national level is needed as future research.

• 한국환경과학회지
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• 제23권8호
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• pp.1523-1536
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• 2014

Restoration is the process of reducing or reversing damage to an ecosystem so that it can function in its original manner. However, many restoration programs do not achieve this. In the Nakdong Estuary, the largest migratory nesting site in the center of the East Asian-Australasian flyway, an estuarine barrage was constructed in the 1980s that required site restoration following its completion in 1987 and the expansion of several large industrial complexes(Noksan and Jangrim) and a residential development(Myeongji). The goal of the restoration was to restore the function of the wetland to its pre-disturbance state. To achieve this, a restoration program was designed consisting of three stages. The first stage(1993-1995), saw the construction of three artificial wetlands(Shinhori, Daemadeung, and Eulsuk), the second(2003-2005) involved the dredging and returning of farmed lands to their natural state, and the third(2008-2012) focused on the rehabilitation and vegetation development of the wetlands. However, the project has not achieved all of the desired goals, and it is an example of the lapses in ecological restoration following anthropogenic disturbance. Issues that resulted in an incomplete restoration included the timing of the stages, noncompliance with the restoration plan, not directly monitoring the restoration or continuing the monitoring following completion of the development project, and the political subversion of the restoration plan. For the success of the restoration plan, it is necessary to avoid mistakes such as inconsistent monitoring, unequal levels of stakeholder involvement, and political interference.

• 한국물환경학회지
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• 제21권4호
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• pp.368-378
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• 2005

Inorganic matters originated from stone quarries and manufacturing plants could alter the ecological characteristics of adjacent aquatic systems, especially the structure and function of benthic macroinvertebrate community. In such situation, the locality of stone quarry and the quantity of inorganic matters would be important factors that determined the disturbing strength to the benthic macroinvertebrate community. Locality patterns of stone quarries were classified into 3 types in relation to the stream ecosystem; stream-proximity, upstream-inclusion and tributary-inclusion type. In the result of species:abundance analysis, stone quarry B (upstream-inclusion type) showed geometric distribution, while others showed broken-stick distribution pattern. The benthic macroinvertebrate communities closer to stone quarries showed smaller species numbers and standing crops among all types of stone quarries. However the values of species evenness index were not seriously different between controls and directly affected sites. These results indicated that the effect of inorganic disturbance would differ from those of organic pollution that induced the highly dominant state occupied by tolerant species. Number of occurred species, standing crops, community indices and biotic indices indicated that the community of upstream-inclusion type was the most seriously damaged from the inorganic disturbance, and the community would be very simple and unstable. Tributary-inclusion stone quarry heavily damaged to tributary system in biologically, but influence to the main stream seemed to be depended on the scale of main stream. Among 3 types of stone quarry localities, stream-proximity type induced the least damages to benthic macroinvertebrate community, though the degrees of damage were different along with distances between stream and stone quarry.