• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.4
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• pp.101-111
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• 2008

To provide more natural elements in the harsh urban environment, 'planting trees as urban forests' has been emphasized as having an important role, and trees are expected to be as functional as the trees under more natural conditions in rural areas, and provide people with benefits. To do this, urban forest policies needed a better idea of planting methods and management of trees through the theory of landscape ecology, and also the feedback system according to the evaluation and assessment of urban forests. In this case study, a new principle and assessment indices for the evaluation are applied for the 4 urban forests in two Korean metropolitan cities, Daejeon and Ulsan. The evaluation of Korean urban forest-function as biotope and the assessment for the classification of biotope diversity types are carried out. The AUEM(Adding Up Estimation Matrix) is applied for the analysis of urban forests. Unlikely previous researches on the other Korean metropolitan cities, the size of urban forest has less influence on the vegetation diversity. The most frequent biotope grade is the 3rd grade at Namseon park and Mt. Hamwol, while Mt. Bomun and Mt. Yeompo show the 4th grade. The grades of forest-function as biotope are from 3rd to 5th in which lower than average in forest-function grades. This means that the 4 sites are still not-matured forests and less-functional forests as the urban biotope.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.2
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• pp.126-139
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• 2007

In the autumn of 2000 and spring of 2001, field surveys were conducted to estimate the effectiveness of artificial reefs (type cube, $2{\times}2{\times}2m^3$) that were established in the four islands of Bangnyeong, Socheong, Daeyeonpyeong and Ganghwa in Kyonggi Bay, the west coast of Korea during 1995 and 1996. The condition of reefs was examined through SCUBA diving and a side-scan sonar. Much of the reefs in Daeyeonpyeong and Ganghwa area were buried in bottom sediment. Despite an intensive search in Bangnyeong area, even a cluster of reefs was not found and most of them seemed to be buried by sand waves. Thus an appropriate investigation on the sediment transport should be included in pre-assessment for the expected performance and protection of artificial reefs. Distribution of average CPUE in natural fishing ground (control) was estimated by bootstrapping simulation and possible comparison of CPUE between control and reef areas (treatment) were made in Bangnyeong and Socheong (Experiment I). Positive reef effect was detected in Socheong but CPUE of treatment in Bangnyeong was varied between or lower than the 99% CPUE confidence intervals of the control. Control/treatment abundance and biomass of fishes and invertebrates were tested by paired t-test and sign test (Experiment II). Only four cases among 22 showed significant positive effect. Based on the results, the cube artificial reef in Socheong was inferred as an affirmative one. Floor type was hypothesized to be one of the probable agents in determining the effectiveness of artificial reefs.

• Journal of Ecology and Environment
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• v.33 no.1
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• pp.3-13
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• 2010

The Tsushima leopard cat, Prionailurus bengalensis euptilurus, a small felid, inhabits only the Tsushima Islands in Japan. Previous studies of the Tsushima leopard cat revealed that natural factors; including sex, reproductive activity, season, and prey distribution and abundance affect leopard cat home range variation and habitat use. In this study, we focused on clarifying how anthropogenic factors influenced home range variation and habitat use of a male Tsushima leopard cat living near a suburban area in January, March, May and September 2005 using radio-tracking. The home range size (100% MCP) of this cat was $0.78\;{\pm}\;0.26\;km^2$ (mean ${\pm}$ SD, n = 4 tracking sessions) across the whole study period. However, the cat did not use all parts of its home range uniformly; rather it used some habitat types selectively. The cat avoided agriculture areas and residential areas in all of the tracking-sessions. On the other hand, the cat showed a weak preference for artificial structures and a strong preference for baiting sites in January and March, while it avoided them in May, and no baiting site was included in its home range in September. These results suggest that anthropogenic factors influenced the ranging patterns and habitat use of the leopard cat living near a suburban area. Artificial structures might provided good resting spaces for the cat in bad weather. When the density of its main prey was low in the winter, the cat tended to rely on artificial prey and had a small home range size.

• Journal of Korean Society on Water Environment
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• v.30 no.3
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• pp.261-268
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• 2014

Four clays (both natural and commercial types) mainly used in Korea were tested for removal efficiency of Microcystis spp. and ecotoxicity on Daphnia magna and Vibrio fischeri. Four clays (clay A~D) were composed of 91.9~100% of sand (0.02~0.2 mm in particle size). Clay D consisted of lager particles than other clays. Major elements of the four clays were $SiO_2$ (45.3~62.8%), $Al_2O_3$ (18.5~29.7%) and $Fe_2O_3$ (5.4~7.9%). They contained kaolinite (clay mineral), quartz, muscovite, and so on. Clay C and D contained montmorillonite, one of the clay minerals improving clay-cell aggregation. For clay A, B and C, removal efficiency of Microcystis spp. was over 60% at 2 g/L. It reached about 100% at over 5 g/L. For clay D, it was over 60% and 95~100% at 5 g/L and 20 g/L respectively. After adding clays, pH decreased. The greatest drop of pH appeared at clay C. Except for addition of 100 g/L clay C, ecotoxicity on D. magna and V. fischeri didn't appeared at all dose of clays.

• Korean Journal of Environment and Ecology
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• v.24 no.6
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• pp.772-780
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• 2010

The golden apple snail-Pomacea canaliculata was an alien species and introduced into Korea as table use in 1983. This species is possible pest in direct seeded rice paddy in Korea. We investigated the effects of this exotic snail on the macrophytes and the water quality in water canal. Also, the basic life cycle of this species and the overwintering ecology in Chungnam and Jeonbuk province were elucidated. A survey of natural water canal in Korea showed that high densities of the snail were associated with absences of macrophytes-Hydrilla verticillata, Ceratophyllum demersum, Spirodela polyrhiza and Lemna perpusilla. Experiments in water tank also demonstrated that the golden apple snail can cause the loss of macrophytes, and increase the EC(Electric conductivity), COD(Chemical oxygen demand), T-N(Total nitrogen) and T-P(Total phosphorus) in water.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.56-63
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• 2013

We have characterized the putative ${\alpha}$-glucosidase gene (st2525) selected by total genome analysis from the acidothermophilic crenarchaeon Sulfolobus tokodaii strain 7. The ORF was cloned and expressed as a fusion protein in Escherichia coli, and recombinant ST2525 was purified by Ni-NTA affinity chromatography. Maximum activity was observed at $95^{\circ}C$ and pH 4.0, and the enzyme exhibited stability with half-lives of 40.1 min and 7.75 min at extremely high temperatures of $100^{\circ}C$ and $105^{\circ}C$, respectively. The enzyme retained at least 85% of its maximal activity in the pH range of 4.0-11.0. ST2525 exclusively hydrolyzed ${\alpha}$-1,4-glycosidic linkages of oligosaccharides in an exo-type manner, with highest catalytic efficiency toward maltotriose. The enzyme also displayed transglycosylation activity, converting maltose to isomaltose, panose, maltotriose, isomaltotriose, etc. From these results, ST2525 could be potentially useful for starch hydrolysis as well as novel synthesis of oligosaccharides in industry.

• Journal of Forest and Environmental Science
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• v.37 no.1
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• pp.62-68
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• 2021

Despite numerous efforts on reducing road-kill worldwide, the collisions have been occurring continuously. Many factors are affecting road-kill occurrences and the effect is various by species. We investigated Hydropotes inermis argyropus road-kill characteristics on the national highway. We examined 9,099 H. i. argyropus road-kill points with distance to the gaps on road (interchange and intersection) and distance to six natural land-cover types as explanatory variables. We also examined the number of road-kill occurrences according to temporal variation using chi-square test with 9,658 events. In general, H. i. argyropus road-kill location tended to occur close to the gaps on road, agricultural lands and forests. The average distance from road-kill to the gap was 694.7 m and 78.6% of the collisions were occurred within 1 km from the gaps. In addition, Kruskal-Wallis test showed the distance between road-kill points and each land cover and the gaps was significantly different. The temporal analyses showed that the differences of the H. i. argyropus road-kill frequency are significant in both month and season. Our results implies H. i. argyropus road-kill location tended to occur close to the gaps on road, agricultural lands and forests in general, especially during May and June, according to their seasonal behavior. Thus, we suggest there is a need of concentrated management on the roads with specific characteristics for both wildlife and human safety.

• Journal of Environmental Science International
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• v.31 no.10
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• pp.861-868
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• 2022

The Namdae stream in Gangneung-si is one of the rivers where salmon stock is mainly maintained by natural spawning rather than artificial seedlings. There are structures including weir, and fish distribution and movement characteristics can be different by these structures. In this study, we investigated the distribution and behavioral characteristics of salmon by sighting survey within 12 km immediately upstream of the river mouth between October 2021 and February 2022. As a result, salmon distributed within 9 km from rivermouth. There were more salmon in the lower reaches of Doosan weir than in the upper reaches of that. The main spawning ground for salmon was between 7-9 km from rivermouth and around the lower part of Doosan weir. Salmon behaved for spawning in the gravel-bed area and undercut slope of the mainstream, such as mating, digging the riverbed, and competition among males. Salmon moved more slowly in the gravel-bed area than sand-bed area. Doosan weir hinders the spawning migration of salmon by frequent flow changes and terraced fishway. This study provides primary information to understand the ecological changes of salmon by environmental changes in the Namdae stream.

• Journal of Ecology and Environment
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• v.36 no.4
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• pp.315-325
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• 2013

Taxa in the order Chlorococcales inhabiting Hongcheon River, South Korea were collected and identified from December 2011 to September 2012. As a result, nine taxa in the Order Chlorococcales including unrecorded genera Oocystidium and Heleococcus were newly added to the Korean flora: Oocystidium ovale, Heleococcus mucicola, Chlorella mirabilis, Monoraphidium convolutum var. pseudosabulosum, M. minutum, Raphidocelis mucosa, Eutetramorus tetrasporus, Scenedesmus flavescens, and S. multicauda. The morphological characteristics of the nine taxa identified in this study mostly corresponded to already reported characteristics; however, M. minutum had a shorter cell length than the recorded description, Raphidocelis mucosa and S. flavescens were larger than previous descriptions, and Scenedesmus multicauda had larger spines than the cell itself. Eight of the nine taxa were found in planktonic samples, whereas Heleococcus mucicola was found in an epilithic sample. Therefore the Korean order Chlorococcales, including these newly reported ones, totals to 255 species.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.929-934
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• 2001

As the notion of environment protection changes throughout the world, construction engineers, as part of the effort to resolve environmental problems, have been actively doing research on environmental friendly porous concrete using large and non-uniform aggregate. Concrete having a great deal of continuous porosity enable water and air to pass freely through firmly hardened material, allowing necessary nutrients to reach roots of vegetation, thereby sustaining them. It is possible to prevent the exhaustion of natural resources by recycling waste concrete and industrial by-products, to reduce damage caused by the destruction of nature through effective management of natural resources, to preserve the natural environment and vegetation in urban areas by activating the soil, protecting the underground ecology system, and growing garden plants through the application of environmentally friendly concrete.