• Korean Journal of Ecology and Environment
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• v.35 no.4 s.100
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• pp.306-311
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• 2002

The amount and composition of dissolved organic carbon in wetlands are of great importance for their influence in secondary productivity, various biogeochemical processes, and aquatic ecosystem functions. In the present study, we measured variations of DOC and phenolics concentrations in pore-water of three northern peatlands (bog, fen, and swamp) over a 1-year period. General microbial activity (soil respirometry) and phenol oxidase enzyme activity were determined in the same peatlands to elucidate mechanisms underlying the differences in DOC and phenolics contents. The concentrations of DOC varied 25.5-45.4 (bog),29.2-71.4 (fen), and 13.5-87.6 (swamp) mg/L, while phenolic concentrations ranged 13.3-48.1 (bog), 7.6-29.5(fen) , and 4.9-30.8 (swamp) mg/L. The seasonal variations of DOC and phenolics in the swamp suggest that litterfall may be one of the most important factors for the DOC dynamics in such systems. The lowest microbial activity and phenol oxidase activity were found in the bog, which appears to Induce high percentage of phenolic contents in pore-water from bogs. It is also suggested that not only the DOC concentrations but also composition of DOC is of great importance in wetland biogeochernistry.

• Korean Journal of Ecology and Environment
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• v.54 no.3
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• pp.170-189
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• 2021

Environmental DNA (eDNA) is a genetic material derived from organisms in various environments (water, soil, and air). eDNA has many advantages, such as high sensitivity, short investigation time, investigation safety, and accurate species identification. For this reason, it is used in various fields, such as biological monitoring and searching for harmful and endangered organisms. To collect eDNA from a freshwater ecosystem, it is necessary to consider the target organism and gene and a wide variety of items, such as on-site filtration and eDNA preservation methods. In particular, the method of collecting eDNA from the environment is directly related to the eDNA concentration, and when collecting eDNA using an appropriate collection method, accurate (good quality) analysis results can be obtained. In addition, in preserving and extracting eDNA collected from the freshwater ecosystem, when an accurate method is used, the concentration of eDNA distributed in the field can be accurately analyzed. Therefore, for researchers at the initial stage of eDNA research, the eDNA technology poses a difficult barrier to overcome. Thus, basic knowledge of eDNA surveys is necessary. In this study, we introduced sampling of eDNA and transport of sampled eDNA in aquatic ecosystems and extraction methods for eDNA in the laboratory. In addition, we introduced simpler and more efficient eDNA collection tools. On this basis, we hope that the eDNA technique could be more widely used to study aquatic ecosystems and help researchers who are starting to use the eDNA technique.

• Journal of Ecology and Environment
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• v.44 no.4
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• pp.275-285
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• 2020

Background: In Korea, Symplocos prunifolia Siebold. & Zucc. is only found on Jeju Island. Conservation of the species is difficult because little is known about its distribution and natural habitat. The lack of research and survey data on the characteristics of native vegetation and distribution of this species means that there is insufficient information to guide the management and conservation of this species and related vegetation. Therefore, this study aims to identify the distribution and vegetation associated with S. prunifolia. Results: As a result of field investigations, it was confirmed that the native S. prunifolia communities were distributed in 4 areas located on the southern side of Mt. Halla and within the evergreen broad-leaved forest zones. Furthermore, these evergreen broad-leaved forest zones are themselves located in the warm temperate zone which are distributed along the valley sides at elevations between 318 and 461 m. S. prunifolia was only found on the south side of Mt. Halla, and mainly on south-facing slopes; however, small communities were found to be growing on northwest-facing slopes. It has been confirmed that S. prunifolia trees are rare but an important constituent species in the evergreen broad-leaved forest of Jeju. The mean importance percentage of S. prunifolia community was 48.84 for Castanopsis sieboldii, 17.79 for Quercus acuta, and 12.12 for Pinus thunbergii; S. prunifolia was the ninth most important species (2.6). Conclusions: S. prunifolia can be found growing along the natural streams of Jeju, where there is little anthropogenic influence and where the streams have caused soil disturbance through natural processes of erosion and deposition of sediments. Currently, the native area of S. prunifolia is about 3300 ㎡, which contains a confirmed population of 180 individual plants. As a result of these low population sizes, it places it in the category of an extremely endangered plant in Korea. In some native sites, the canopy of evergreen broad-leaved forest formed, but the frequency and coverage of species were not high. Negative factors that contributed to the low distribution of this species were factors such as lacking in shade tolerance, low fruiting rates, small native areas, and special habitats as well as requiring adequate stream disturbance. Presently, due to changes in climate, it is unclear whether this species will see an increase in its population and habitat area or whether it will remain as an endangered species within Korea. What is clear, however, is that the preservation of the present native habitats and population is extremely important if the population is to be maintained and expanded. It is also meaningful in terms of the stable conservation of biodiversity in Korea. Therefore, based on the results of this study, it is judged that a systematic evaluation for the preservation and conservation of the habitat and vegetation management method of S. prunifolia should be conducted.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.305-313
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• 2011

Fertilization is essential to seedling production in nursery culture, but excessive fertilization can contaminate surface and ground water around the nursery. The objective of this study was to find optimal fertilization practice of container seedling production for reducing soil and water contamination around the nursery without compromising seedling quality. This study was conducted to investigate growth performance, photosynthesis, chlorophyll fluorescence, and chlorophyll contents of Liriodendron tulipifera growing under three different fertilization treatments (Constant rate, Three-stage rate, and Exponential rate fertilization). Root collar diameter, height, and biomass of L. tulipifera were the highest at Constant treatment. Like growth performance, seedling quality index (SQI) were higher at Constant than at other treatments, but not significantly different among treatments. L. tulipifera showed good photosynthetic capacity at all treatments. Photochemical efficiency and chlorophyll contents were significantly lower at Exponential than at other treatments. Therefore, Exponential fertilization which is 50% fertilizer of other treatments would maximize seedling growth and minimize nutrient loss.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.565-576
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• 2011

This study was conducted to describe forest stand characteristics of the habitats of Allium victorialis var. platyphyllum population from the ecological analysis of classification of vegetation types, importance values, species diversity, interspecific association and community similarity in Ulleung Island and Mt. Hambaek, in which investigated by 48 plots ($10m{\times}10m$). The vegetation studied was classified into 1 community group, 2 communities, 2 groups and 3 subgroups for a species unit and divided by 5 units for a vegetation unit. In the Fagus engleriana group (vegetation unit 1, 2 and 3), importance value of A. victorialis var. platyphyllum in herb layer showed relatively higher value than other units. Importance value of A. victorialis var. platyphyllum in herb layer had higher value. In the analysis of interspecific association, most of the species associated positively to A. victorialis var. platyphyllum belonged to habitat features of valley area and sub-alpine zone. Therefore, it was considered that the growing environment of A. victorialis var. platyphyllum population was closely correlated to soil moisture and air humidity.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.245-257
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• 2021

Ulleungdo, a volcanic island, has different climate, soil, and topography characteristics from inland of the Korean Peninsula. Its agriculture also exhibits distinctive features. This study focused on floristic compositions and characteristics of crop lands in Ulleungdo. Flora surveys were conducted for 37 areas three times, one in May of 2016, one in July of 2020, and one in August of 2020. Results showed that vascular plants of crop lands in Ulleungdo included 186 taxa of 53 families, 132 genera, 160 species, 14 varieties, five subspecies, and five hybrids. Asteraceae had the most diverse species (33 taxa), followed by Poaceae (25 taxa), Fabaceae (12 taxa), Polygonaceae (11 taxa), and Liliaceae (nine taxa). The biological type of crop lands in Ulleungdo island was determined to be Th-R₅-D₄-e type. Rare plants were found for nine taxa: Athyrium acutipinnulum Kodama ex Nakai, Sedum takasimense Nakai, Rubus takesimensis Nakai, Dystaenia takesimana (Nakai) Kitag., Ligustrum foliosum Nakai, Aster pseudoglehni Y.Lim, Cirsium nipponicum (Maxim.) Makino, Lilium hansonii Leichtlin ex D.D.T.Moore, and Polygonatum robustum (Korsh.) Nakai. In addition, 45 taxa contained naturalized plants of 13 families, 33 genera, 44 species, and one variety. Urbanization and naturalization indices were 13.9%, and 24.2%, respectively.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.6
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• pp.1-13
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• 2021

This study was performed to investigate the ecosystem service patterns in relation to climate change acceleration utilizing big data analysis. This study aimed to use big data analysis as one of the network of views to identify convergent thinking in two fields: climate change and ecosystem service. The keywords were analysed to ascertain if there were any differences in the perceiving problems, policy direction, climate change implications, and regional differences. In addition, we examined the research keywords of each continent, the centre of ecosystem service research, and the topics to be referred to in domestic research. The results of the analysis are as follows: First, the keyword centrality of climate change is similar to the detailed indicators of The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) regulations, content, and non-material ecosystem services. Second, the cross-analysis of terms in two journals showed a difference in value-oriented point; the Ecosystem Service Journal identified green infrastructure as having economic value, whereas the Climate Change Journal perceives water, forest, carbon, and biodiversity as management topics. The Climate Change Journal, but not the former, focuses on future predictions. Third, the analysis of the research topics according to continents showed that water and soil are closely related to the economy, and thus, play an important role in policy formulation. This disparity is due to differences in each continent's environmental characteristics, as well as economic and policy issues. This fact can be used to refer to the direction of research on ecosystem services in Korea. Consistent with the recent trend of expanding research regarding the impacts of climate change, it is necessary to study strategies to scientifically predict and respond to the negative effects of climate change.

• Journal of Ecology and Environment
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• v.46 no.3
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• pp.154-160
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• 2022

Background: The mango is one of the essential fruit trees for the economy of Thailand. Mango pollination relies primarily on insects. Other external forces, such as wind, are less efficient since pollen is sticky and aggregating. There is only one report from Thailand on the use of bees as mango pollinators. The study of the behavior and pollination efficiency of honey bees (Apis mellifera) and stingless bees (Tetragonula laeviceps species complex) was conducted in Nam Dokmai mango plantings in Phrao and Mae Taeng districts, Chiang Mai province, between February and March 2019. Results: Our results reveal that the honey bees commenced foraging earlier than the stingless bee. The number of flowers visited within 1 minute by honey bees was higher than that visited by stingless bees. The average numbers of honey bees and stingless bees that flew out of the hive per minute from 7 a.m. and 6 p.m. in the Phrao district were 4.21 ± 1.62 and 9.88 ± 7.63 bees/min, respectively, i.e., higher than those observed in Mae Taeng, which were 3.46 ± 1.13 and 1.23 ± 1.20 bees/min, respectively. The numbers of fruits per tree were significantly higher in the honey bee and stingless bee treatments (T1 and T2) than in the open pollination treatment (T3). The number of fruits between T1 and T2 treatments was not different. In the pollinator exclusion treatment (T4), no fruit was produced. Fruit size factors were not significantly different among T1, T2, and T3 treatments. Conclusions: Our results showed that insect pollination is crucial for mango production, especially with the Nam Dokmai variety in Northern Thailand. As pollinator exclusion treatment showed no fruit set, and pollinator treatment significantly increased the fruit sets compared to open access plots, a managed pollinator program would benefit the mango growers for better productivity. Both the honey bee and the stingless bee were shown to be effective as pollinators.

• Korean Journal of Ecology and Environment
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• v.56 no.2
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• pp.127-139
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• 2023

Daechung Reservoir has been suffering from severe cyanobacterial blooming periodically due to the water pollutants from the watershed, especially nutrients from nonpoint sources. As a countermeasure, an artificial wetland was constructed to mitigate the pollutant load from the watershed by utilizing the vegetation. We investigated the water quality of the influent and outflow of the wetland during years 2014~2020 to evaluate the performance of pollutant removal through the wetland. Major pollutants (e.g. BOD, COD, SS, T-N, and T-P) were largely reduced during the retention in the wetland while nutrients removal was more efficient than that of organic matters. Pollutant removal efficiency for different inflow concentrations was also investigated to estimate the wetland's capability as a way of managing nonpoint sources. The efficiency of water treatment was significantly higher when inflow concentrations were above 75^th percentile for all pollutant, implying the wetland can be applied to the pre-treatment of high pollution load including initial rainfall runoff. Furthermore, the yearly variation of removal efficiency for seven years was analyzed to better understand long-term trends in water treatment of the wetland. The annual treatment efficiency of T-P was very high in the early stages of vegetation growth with high concentration of inflow water. However, it was confirmed that the concentration of inflow water decreased, vegetation stabilized, and the treatment efficiency gradually decreased as the soil was saturated. The findings of the study suggest that artificial wetlands can be an effective method for controlling harmful algal blooms by alleviating pollutant load from the tributaries of Daechung Reservoir.

• Journal of Ginseng Culture
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• v.6
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• pp.51-79
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• 2024

In the 1970s and 1980s, during the nascent phase of ginseng disease research, efforts concentrated on isolating and identifying pathogens. Subsequently, their physiological ecology and pathogenesis characteristics were scrutinized. This led to the establishment of a comprehensive control approach for safeguarding major aerial part diseases like Alternaria blight, anthracnose, and Phytophthora blight, along with underground part diseases such as Rhizoctonia seedling damping-off, Pythium seedling damping-off, and Sclerotinia white rot. In the 1980s, the sunshade was changed from traditional rice straw to polyethylene (PE) net. From 1987 to 1989, focused research aimed at enhancing disease control methods. Notably, the introduction of a four-layer woven P.E. light-shading net minimized rainwater leakage, curbing Alternaria blight occurrence. Since 1990, identification of the bacterial soft stem rot pathogen facilitated the establishment of a flower stem removal method to mitigate outbreaks. Concurrently, efforts were directed towards identifying root rot pathogens causing continuous crop failure, employing soil fumigation and filling methods for sustainable crop land use. In 2000, adapting to rapid climate changes became imperative, prompting modifications and supplements to control methods. New approaches were devised, including a crop protection agent method for Alternaria stem blight triggered by excessive rainfall during sprouting and a control method for gray mold disease. A comprehensive plan to enhance control methods for Rhizoctonia seedling damping-off and Rhizoctonia damping-off was also devised. Over the past 50 years, the initial emphasis was on understanding the causes and control of ginseng diseases, followed by refining established control methods. Drawing on these findings, future ginseng cultivation and disease control methods should be innovatively developed to proactively address evolving factors such as climate fluctuations, diminishing cultivation areas, escalating labor costs, and heightened consumer safety awareness.