• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.247-255
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• 2023

The occurrence of sudden strike pest events in urban areas is increasing as global warming intensifies, consequently, re causing harmful impacts. Studies on these incidents are fewer in number and insufficient compared to research on other nuisances such as mosquitoes and flies. Therefore, we conducted a study on the development of a selective collection method, using a filter layer to establish a monitoring system for Ephemera orientalis (Ephemeroptera: Ephemeridae), a species frequently identified as a sudden strike pest. Three sampling points were selected along the Hangang River in Namyangju, where E. orientalis outbreaks occur. Prototypes, consisting of four layers and with a light source attached to attract insects, were installed at each sampling point. Sampling was performed every 30 minutes between 19:00 and 22:30 in the month of June. The filter interval of each layer was adjusted so that the collected mayflies were distributed into specific layers. To evaluate the collection efficiency in line with the materials and the filter intervals, the optimal collection efficiency was investigated by combining two types of layer materials (stainless and acrylic) and filter intervals (1-5 mm). The optimal conditions were as follows: The selective collection efficiency was found to be highest at 96.5% when the interval of the selective target filter was 2.0 mm and there was one upper filter.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.283-290
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• 2023

The Republic of Korea reclaimed land to increase its food self-sufficiency rate, but the yield was reduced due to abnormal climate. In this study, it was hypothesized that rapid and continuous monitoring technology could help improve yield. Using the vegetation index (VI) analysis, the drought stress index was calculated and the drought stress for corn grown in Hwaong, Saemangeum, and Yeongsan River reclaimed tidal land was predicted according to drying treatment. The vegetation index of corn did not decrease during the last 20 days of irrigation when soil moisture rapidly decreased, but decreased rapidly during the 20 days after irrigation. The reduction rate of the vegetation index according to the drying treatment was in the order of Saemangeum>Yeongsan River>Hwaong reclaimed tidal land, and normalized difference vegetation index(NDVI) decreased by approximately 50% in all reclaimed tidal lands, confirming that drought stress occurred due to the decrease in moisture content of the leaves. In addition, structure pigment chlorophyll index (SIPI) and photochemical reflectance index (PRI), which are calculated based on changes in light use efficiency and carotenoids, were reduced; drought stress caused a decrease in light use efficiency and an increase in carotenoid content. Therefore, vegetation index analysis was confirmed to be effective in evaluating and predicting drought stress in corn growing on reclaimed tidal land corn.

• Journal of Wetlands Research
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• v.26 no.1
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• pp.32-40
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• 2024

The purpose of this study is to collect basic information about Narrow-mouthed Toad (Kaloula borealis) by analyzing the morphological characteristics of Narrow-mouthed Toad (Kaloula borealis) caught in pitfall traps. The study site is in Godeok-dong, Gangdong-gu, Seoul, and a total of 1,063 individuals were captured using pitfall traps for a total of four years from July 2016 to November 2020. Narrow-mouthed Toad (Kaloula borealis) were classified into adult and immature individuals based on length (SVL), and differences in sex ratio and shape were confirmed for adults. As a result, all adult males had a pair of white bands observed in the abdomen, and females had eggs identified in the abdomen. Through previous studies, a pair of white bands on the abdomen were determined to be male gonads, and were also confirmed in some immature individuals. The sex of the Narrow-mouthed Toad (Kaloula borealis) could be distinguished by the presence or absence of a pair of white bands located on the abdomen, and it is believed that this can be used as a sex classification method that can be confirmed in the field. During the study period, the adult sex ratio was confirmed to be 697 male (65.57%) and 366 female (34.43%), with more males. It is expected that this method of sex ratio and male/female sex ratio will be used not only for species restoration and monitoring of migration and alternative habitats due to development, but also as basic data for various ecological studies.

• Journal of the Korea Society for Simulation
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• v.33 no.1
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• pp.1-17
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• 2024

Forest management is known to beneficially influence stand structure and wood production, yet quantitative understanding as well as an illustrative depiction of the effects of different management approaches on tree growth and stand dynamics are still scarce. Long-term management of beech forests must balance public interests with ecological aspects. Efficient forest management requires the reliable prediction of tree growth change. We aimed to develop a novel hybrid simulation approach, which realistically simulates short- as well as long-term effects of different forest management regimes commonly applied, but not limited, to German low mountain ranges, including near-natural forest management based on single-tree selection harvesting. The model basically consists of three modules for (a) natural seedling regeneration, (b) mortality adjustment, and (c) tree growth simulation. In our approach, an existing validated growth model was used to calculate single year tree growth, and expanded on by including in a newly developed simulation process using calibrated modules based on practical experience in forest management and advice from the local forest. We included the following different beech forest-management scenarios that are representative for German low mountain ranges to our simulation tool: (1) plantation, (2) continuous cover forestry, and (3) reserved forest. The simulation results show a robust consistency with expert knowledge as well as a great comparability with mid-term monitoring data, indicating a strong model performance. We successfully developed a hybrid simulation that realistically reflects different management strategies and tree growth in low mountain range. This study represents a basis for a new model calibration method, which has translational potential for further studies to develop reliable tailor-made models adjusted to local situations in beech forest management.

• Korean Journal of Ecology and Environment
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• v.57 no.3
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• pp.162-168
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• 2024

The purpose of this study was to record for the first time in Korea the presence of Melanoides tuberculata (an invasive alien species), which was confirmed during the "National Survey on the Status of Alien Species" in Jukdang stream (also known as Guppy Stream, located in Icheon, Gyeonggi Province), which is affected by the year-round discharge of heated effluent from a large semiconductor factory and where various tropical organisms, including ornamental fish, appear due to artificial release. A Total of 52 specimens were collected, and they can be visually distinguished from native melanian snails by their reddish-brown flames and spots. Genetic analysis further confirmed the species as Melanoides tuberculate. Melanoides tuberculata typically inhabits tropical climates, but its presence has been confirmed in altered aquatic environments such as Jukdang stream, where the water temperature remains warm even in a temperate climate. This indicates the need for further monitoring of domestic streams with similar conditions, particularly those receiving heated effluent, like Jukdang stream. Additionally, due to its strong reproductive capacity, including parthenogenesis, and its adaptability to various environments, there have been cases where the populations of Pomacea lineata and Aylacostoma tenuilabris have declined. This suggests that Melanoides tuberculata may have a competitive advantage in interspecific competition, potentially suppressing native species populations if it spreads within the domestic ecosystem. Melanoides tuberculata serves as an intermediate host for parasites that can cause diseases in both humans and animals, raising public health concerns in many countries. There is also a significant risk that it could be mistaken for native melanian snail species and consumed, which necessitates a high level of caution.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2182-2189
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• 2024

The high-purity germanium gamma-ray spectrometer was used to measure the radioisotope in surface water of lakes in a Chinee petroleum industrial area. 92 samples were collected from surface water of three lakes. Activity concentrations of ²³²Th, ²²⁶Ra and ⁴⁰K in three lakes were measured, distributed in the range of 101.8-209.4, 192.1-224.9 and 335.0-548.9 mBq/L, respectively. Results were all within the limits of WHO and China. Potential environmental and health risks were assessed by calculating some radiation hazard indicators, radium equivalent index, annual effective dose, excess lifetime cancer risk, absorbed dose rate, external hazard index, internal hazard index, annual gonadal dose equivalent, activity utilization index and representative gamma index, which ranged 0.38-0.54 Bq/L, 0.06-0.08 mSv/y, 0.23 × 10^-3-0.31 × 10^-3, 0.17-0.24 nGy/h, 1.01 × 10^-3-1.46 × 10^-3, 1.55 × 10^-3-2.02 × 10^-3, 1.16-1.66 μSv/y, 3.13 × 10^-3-4.45 × 10^-3 and 2.60 × 10^-3-3.77 × 10^-3. The results were all at acceptable levels, meaning no impact on human health. The relationship between the electrical conductivity of surface water and the activity concentration of ²³²Th, ²²⁶Ra and ⁴⁰K was evaluated. The electrical conductivity value was 0.241-0.369 mS/cm, showing a significant correlation coefficient between ²²⁶Ra and ⁴⁰K and electrical conductivity. Multivariate statistical methods were used to determine the relationship between the activity concentrations of ²³²Th, ²²⁶Ra, and ⁴⁰K, radiation hazard indicators and electrical conductivity.

• Journal of Korean Society of Forest Science
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• v.113 no.3
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• pp.271-281
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• 2024

The purpose of this study is to establish baseline data on the habitat status of Dracocephalum argunense Fisch. ex Link by identifying its vegetation structure and correlating environmental factors. A total of 9 vegetation plots (10 m×10 m) were surveyed. Cluster analysis revealed a total of three clusters: Quercus aliena (Group 1), Pinus thunbergii-Rubus parvilolius (Group 2), and Indigofera kirilowii-Zanthoxylum piperitum (Group 3). The importance value of D. argunense was the highest in Group 2, with a value of 6.19. Diversity analysis indicated a range of 2.747-3.166, but differences among the groups was not statistically significant (p>0.05). In the areas surrounding sedimentary rock zones, invasive plants were identified as indicator species, emphasizing the need for monitoring invasive species in the future. Although D. argunense exhibits good adaptability to moisture and atmospheric conditions due to its diverse habitats (forest and coast), there is a risk of decline due to interspecific competition and human activities, as analyzed in this study.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.42 no.2
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• pp.33-46
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• 2024

This study analyzes the planting status of alien plants in Gongsanseong, a UNESCO World Heritage Site. It provides ecological information necessary to maintain and manage traditional landscapes and environments. Vascular flora was identified as 174 taxa (88.3%) of native plants, 21 taxa (10.7%) of alien plants, and 22 taxa (11.2%) of naturalized plants among the total 197 taxa. As for rare plants, endangered species (CR) Magnolia kobus DC. appeared, accounting for 0.5% of all plant species. Endemic plants were not identified. As for the invasive alien plants, 21 taxa were identified, such as the Rumex obtusifolius L and Sicyos angulatus L. As for the degree of spread, mild spread (MS) was identified as 7 taxa (35.0%), severe spread (SS) as 2 taxa (10.0%), and extensive spread (WS) as 10 taxa (50.0%). As for naturalized plants, 22 taxa were naturalized, followed by 8 taxa of Asteraceae and 4 taxa of Fabaceae. The urbanized index was 10.7% and the naturalized plants ratio was 6.5%. The management plan is to identify the location, size and growth information of each plant species in advance through continuous monitoring using experts. It is possible to establish an annual removal project plan based on basic information on alien species.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.115-123
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• 2020

The vertical distribution of vegetation can be classified according to the altitudinal gradient and the distribution of species along this gradient. The purpose of this study was to analyze the vegetation structure, species composition, dimensional density, and change according to altitude. These data illustrate the distribution of coniferous forest by altitude. By order of importance, the vegetation structure of this mixed forest consisted of Abies nephrolepis (12.2), Pinus koraiensis (10.86), and Acer komarovii (8.11). As a result of species composition according to the altitude, A. nephrolepis and Maianthemum bifolium increased in importance with increasing altitude. Tripterygium regelii emerged between 1,400 m and 1,600 m, which indicates that forest gaps were frequent at that elevation. The species diversity index was the highest from 1,400-1,500 m and coincided with the presence of forest gaps. The changes in A. nephrolepis of evergreen conifers increased significantly from 402 ± 5.4 ha.^-1 to 528 ± 11.6 ha.^-1 for two years, and decreased from 57 ± 1.3 ha.^-1 to 56 ± 1.6 ha.^-1 for P. koraiensis. The density of A. nephrolepis and P. koraiensis seedlings significantly increased at 1,500-1,600 m. The results of this study can be used as a basis to identify the mast seeding year with the increase or decrease of seedlings. In addition to documenting the evergreen conifer population of the Seorak Mountain, these results can be built upon for future monitoring of seedlings mortality.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.895-903
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• 2007

As for the increasing demanding on the development of direct-ecological landfill monitoring methods, it is needed for critically defining the condition of landfills and their influence on the environment, quantifying the amount of enzymes and bacteria mainly concerned with biochemical reaction in the landfills. This study was thus conducted to understand the fates of contaminants in association with groundwater quality parameters. For the study, groundwater was seasonally sampled from four closed unsanitary landfills(i.e. Cheonan(C), Wonju(W), Nonsan(N), Pyeongtaek(P) sites) in which microbial diversity was simultaneously obtained by 16S rDNA methods. Subsequently, a number of primer sets were prepared for quantifying the specific gene of representative bacteria and the gene of encoding enzymes dominantly found in the landfills. The relationship between water quality parameters and gene quantification were compared based on correlation factors. Correlation between DSR(Sulfate reduction bacteria) gene and BOD(Biochemical Oxygen Demand) was greater than 0.8 while NSR(Nitrification bacteria-Nitrospira sp.) gene and nitrate were related more than 0.9. A stabilization indicator(BOD/COD) and MTOT(Methane Oxidation bacteria), MCR(Methyl coenzyme M reductase), Dde(Dechloromonas denitrificans) genes were correlated over 0.8, but ferric iron and Fli(Ferribacterium limineticm) gene were at the lowest of 0.7. For MTOT, it was at the highest related at 100% over BOD/COD. In addition, anaerobic genes(i.e., nirS-Nitrite reductase, MCR. Dde, DSR) and DO were also related more than 0.8, which showing anaerobic reactions generally dependant upon DO. As demonstrated in the study, molecular biological investigation and water quality parameters are highly co-linked, so that quantitative real-time PCR could be cooperatively used for assessing landfill stabilization in association with the conventional monitoring parameters.