• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.259-273
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• 2022

Interactions between species in a community are very complex, and they are visualized and analyzed through a food web in simple way. Food web is a network of species connected by trophic links showing energy flow from prey to predator. Various models were developed to characterize the food web in ecosystems. In this study, we classified food web models to static models such as Ecopath and dynamic models such as AQUATOX. We presented characteristics of several different types of food web models in each category, and reviewed their applications used in aquatic ecosystems. Finally, we presented issues to be considered to develop food web models.

• Journal of Ecology and Environment
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• v.46 no.1
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• pp.76-84
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• 2022

Background: Climate and livestock grazing are key agents in determining current Mongolian steppe vegetation communities. Together with plant coverage or biomass, palatability of steppe community is regarded as a useful indicator of grassland degradation, in particular, at grazing hotspots in arid and semi-arid grasslands. This study analyzed relationships between livestock grazing pressure and steppe vegetation palatability at three summer pastures with different aridity (dry, xeric, and mesic) and livestock numbers (1,100, 1,800, and 4,100 sheep units, respectively). At each site, it was surveyed coverage, biomass, and species composition of different palatability groups (i.e., palatable [P], impalatable [IP], and trampling-tolerant [TT]) along a 1-km transect from grazing hotspots (i.e., well) in every July from 2015 to 2018. Results: In results, total vegetation coverage increased with wetness, 7 times greater at mesic site than dry one in averages (33.1% vs. 4.5%); biomass was 3 times higher (47.1 g m^-2 vs. 15.7 g m^-2). Though P was the dominant palatability group, the importance of IP in total coverage increased with aridity from mesic (0.6%) to dry (40.2%) sites. Whereas, TT increased with livestock numbers across sites. Locally, IP was observed more frequently near the wells and its spatial range of occurrence becomes farther along the transects with aridity across sites from mesic (< 100 m) to dry (< 700 m from the well). Conclusions: Our results showed that the importance of IP and its spatial distribution are different at both local and regional scales, indicating that the palatability parameters are sensitive to discern balance between selective-grazing demand and climate-driven foraging supply in Mongolian rangelands.

• Journal of Ecology and Environment
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• v.47 no.3
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• pp.157-167
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• 2023

Background: The most hazardous wastewater sources in the northern part of the Middle Nile Delta, Egypt; receiving a massive amount of agricultural, industrial, and sewage drainage are Kitchener drain which is one of the tallest drainage systems, and Burullus Lake which represents the 2nd largest Egyptian coastal lake. Results: The current work is to determine the abundance and frequency of cyanophytes, chlorophytes, and bacillariophytes and the correlation between them and environmental abiotic components. Among sixty nine microalgal species, 19 species are belong Cyanophyta, 26 belong Chlorophyta and 24 belong Bacillariophyta. Genus Scenedesmus (Chlorophyta) was the most abundant in the study area (13 species), followed by Genus Oscillatoria (9 species) and Genus Navicula (7 species). Nostoc muscorum and Chlorella vulgaris were the most common and recorded in all sites (100% of the locations) under study. The application of the two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis revealed agglomerating of 4 groups (communities) at 4th level of classification and reasonable segregation between these groups. Zinc, cadmium and lead were showed the highest levels (0.26±0.03, 0.26±0.06, and 0.17±0.01 ppm, respectively). Conclusions: The correlation analysis between water and community variables indicated a high negative correlation of total algae richness with nickel (r = -0.936, p < 0.01). Cyanophyta and Bacillariophyta were correlated negatively (r = -0.842, p < 0.01). However, Chlorophyta showed a negative richness with each of Ni and Pb (r = -0.965, -0.873, respectively) on one hand and a high positive correlation was revealed (r = 0.964) with all environmental variables on the other hand.

• Nutrition Research and Practice
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• v.17 no.5
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• pp.945-958
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• 2023

BACKGROUND/OBJECTIVES: Food literacy (FL) is a crucial skill for selecting sustainable and healthy food options, necessitating the identification of vulnerable groups in the community using valid measurement tools. Identifying weak domains in FL is essential for enhancing the overall FL. This study examined the FL levels of Seoul citizens based on their sociodemographic characteristics and assessed the relationship between FL, food intake, and weight status. SUBJECTS/METHODS: This study utilized the data from the Seoul Food Survey, a cross-sectional study employing representative samples of Seoul citizens. Data collection occurred from September to October 2021, with 4,039 citizens aged 18 yrs and above participating in face-to-face surveys. Thirty-three FL items were assessed, comprising 14 items in the nutrition and safety (NS) domain, eight items in the cultural and relational (CR) domain, and 11 items in the socio-ecological (SE) domain. In addition, data on food intake sufficiency and obesity status were collected. The descriptive statistics, t-tests, analysis of variance, and logistic regression analysis were used for analysis. RESULTS: Men, students, young adults, older citizens, and people experiencing food insecurity had the lowest scores for all the FL domains. The highest quartile group of NS scores had a higher probability of consuming adequate servings of vegetables and fruits, with significant linear trends observed (P for trend < 0.05). In all three FL domains, the odds ratio for obesity was significantly lower in the groups with high FL scores (P < 0.05). CONCLUSIONS: A close relationship was observed between low FL, obesity, and food intake, even after controlling for other covariates. Vulnerable groups with low FL were also identified. Therefore, it is essential to develop programs to improve FL and the health and well-being of these groups.

• Nutrition Research and Practice
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• v.17 no.6
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• pp.1155-1169
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• 2023

BACKGROUND/OBJECTIVES: Unhealthy food choices among young adults are common globally, and the incidence of chronic diseases, such as obesity, is rising. Food literacy (FL) is important for improving and maintaining individual health in a rapidly changing food environment and can form the basis for following a sustainable diet. Therefore, it is essential to improve FL among young adults, particularly college students, who are in the formative years of their lifelong food habits. This study examined the facilitators and barriers of FL and related dietary behavior among college students in South Korea. SUBJECTS/METHODS: This study recruited 25 college students with different residence types using convenience and snowball sampling. In-person, telephone, and video interviews were conducted from March to November 2021. The interview data were analyzed using framework analysis based on the socio-ecological model. RESULTS: At the individual level, prior good experiences with food were the most frequently mentioned facilitator. In contrast, the major barriers were a lack of knowledge, financial hardship, irregular schedules, and academic stress. At the interpersonal level, the influences of family and peers, such as early exposure to healthy eating habits and opportunities to have easy accessibility to farms and farming, are major facilitators, but the lack of a sense of community was the major barrier. At the environmental level, the major barriers were unfavorable food environments at home and in neighborhoods, such as the absence of kitchens in housing and large packaging of produce at markets. CONCLUSIONS: Many factors affected the students' FL and related healthy eating practices. These findings suggest that a campus-based FL program should be developed by reflecting on these facilitators and barriers.

• Korean Journal of Environmental Biology
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• v.35 no.1
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• pp.83-94
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• 2017

Benthic macroinvertebrates were investigated in thermal discharge that flows Buso stream region from December 2015 to February 2016, Korea. Study site was selected for the upstream, downstream relative to the mixing station and mixing station which thermal effluent flows, water quality analysis and benthic macroinvertebrates composition, taxa of EPT-group individuals, analysis of biological water quality. As a result, a total of 4,015 individuals including 50 species, 30 families, 11 orders, 4 classes, and 3 phyla were recognized. Taxa of species is Ephemeroptera 16 species (32.0%) including 6 families, the density composition was highest in 1,848 individuals (46.03%) Diptera. EPT-group occupied during the study period were a total of 1,876 individuals (46.72%) including 32 species and 17 family, lowest in the mixing station for study period. As a results of community analysis, mixing station in the Limnodrilus gotoi and Chironomidae sp.2, which is dominated by the analysis was Ecdyonurus levis, Cincticostella levanidovae, Nemoura KUa. The dominant species showed a difference in the upstream and downstream. In the functional feeding groups, in the upstream and mixing station Gathering-Collectors, downstream it was analyzed that the ratio of the highest Filtering-Collectors and decreased the ratio of Shredders increasing from upstream to downstream. Habitat orientation group is analyzed that accounted for most of the Clingers and Burrowers, from upstream to downstream toward the higher the ratio of Clingers. Biological water quality assessment results were analyzed the worst state in the mixing station with an average 2.73 (${\pm}0.41$). Correspondence analysis, correlation analysis results of water temperature and the cold-water species, as the water temperature increases were analyzed by reducing cold-water species and EPT-group.

• Korean Journal of Environmental Biology
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• v.28 no.2
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• pp.86-94
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• 2010

This study compares and contrasts the dynamics of plankton in 31 temperate lakes and reservoirs, and considers particularly the biomass ratio of zooplankton to phytoplankton and ecological model application. A total of 89 species of zooplankton were identified (70 rotifers, 14 cladocerans and 5 copepods) and a total of 554 species of phytoplankton were identified (176 Bacillariophyceae, 237 Chlorophyceae, 68 Cyanophyceae, and 73 other algal taxa). The total plankton abundance and species diversity were showed distinctive spatial and seasonal variation. Annual average phytoplankton density was $7,350{\pm}15,592$ cells $mL^{-1}$ (n=124), and the lowest was $855{\pm}448$ cells $mL^{-1}$ (n=4), while the highest was $72,048{\pm}13,4631$ cells $mL^{-1}$ (n=4). For zooplankton, small rotifer groups dominated the study sites, and approximately 3~10 species appeared in the study sites. Statistical analysis and an ecological model application revealed that the size of reservoirs affected the structure size of plankton community, i.e. relatively large number of species were found in smaller reservoirs. From this result, we can conclude that management strategy for the reservoir environment has to be focused more on small-size reservoirs, in terms of plankton community ecology.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.129-138
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• 2012

We investigated an ecological impact of drought simulated by discharge depletion on the water quality and benthic diatom community in the indoor experimental channel. As artificial substrates slide-glass was installed in acrylic channel for 16 days. Channels were supplied continuously with eutrophic lake water with a discharge rate of 6 L $min^{-1}$ in duplication during the colonized period. And then during the discharge depletion period, three discharge rates were provided: NDF (No depletion of flow rate (Control): 6 L $min^{-1}$), LDF (Low depletion of flow rate: 3 L $min^{-1}$) and HDF (High depletion of flow rate: 1 L $min^{-1}$). Environmental factors in the water, such as suspended solid, Chl-$a$ and nutrients concentration, were measured with periphytic algae including AFDM (ash free dry matter), Chl-$a$ concentration and cell density at 1-day intervals. Light intensity increased significantly with discharge depletion (F=229.5, p= 0.000). $NH_4$-N concentration was highest at HDF. Suspended solid in outflowing water decreased at HDF (88%), LDF (97%) and NDF (99%), compared to inflowing water (100 %). Chl-$a$ in substrates increased more than two times at LDF and HDF than NDF (F= 8.399, p=0.001). Also AFDM and benthic diatom density increased significantly at LDF and HDF than NDF (F=9.390, p=0.001; F=6.088, p=0.007). In all experimental groups, $Aulacoseira$ $ambigua$, $Achnanthes$ $minutissima$ and $Aulacoseira$ $granulata$ were dominant species accounting for greater than 10% of benthic diatom density. The most dominant species, $A.$ $ambigua$ was highest at LDF, followed by HDF and NDF (F=8.551, p=0.001). In conclusion, the effect of drought simulated by discharge depletion in an artificial stream ecosystem caused significant changes on water quality and benthic diatom biomass. This result provides a useful data to understand the effect of draught on stream ecosystem in situ.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.138-144
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• 1986

This trial was carried out to find out the methods of improvement of natural pasture by PK-fertilization and sheep grazing. The experimental area covered with the community of Carex ferruginea-dominated and located at the Bavarian Alps in the southern part of Germany. As measuring the changes of the vegetation, the Releve-method, the Point-Intercept-method and the Quadrat-Charting-method were applied. Changes in the ecological evidence of the vegetation were studied during the period from April 1980 to the end of growing season in 1983. 1. The fodder value at the oversown pasture we slightly increased by PK-fertilization with sheep grazing, byt that gradually decreased by grazing without fertilization. 2. The pasture quality at the secondary vegetation was greatly improved as well as that of the oversown pasture in Autumn of the second experimental year by sheep grazing with PK-fertilization, but the fodder value was not like that by grazing without fertilization at the natural pasture. 3. The influence of phosphorus/ potassium-fertilization was much more serious than that of sheep grazing. Sedges almost disappeared due to fertilization, on the other hand grasses and legumes increased distinctly. Sheep grazing without fertilization led to a gradual decrease of legumes. The enormous biomass difference in sedges between the June and October analyses was due to a lack of regenerative capacity. 4. The plant community of Carex ferruginea-dominated before the experiment was successived into Alchemillo-Cynosuretum by PK-fertilization with sheep grazing.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.23 no.2
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• pp.91-108
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• 2018

An ecological study on subtidal macrobenthic fauna was conducted from 25 stations in the estuarine area of Wando-Doam Bay, southern coast of Korea during August 2013. A total of 186 species was collected with a mean density of $1,229ind./m^2$ and a mean biomass of $265.7g/m^2$. Polychaetes showed the richest benthic fauna comprising 43% of total fauna, whereas mollusks appeared as density- and biomass-dominant fauna accounted for 45% and 48% of the mean density and biomass, respectively. The number of species and mean faunal density were relatively higher at the stations surrounded by Sinjido, Joyakdo and Gogeumdo showing a gradual decrease toward inner bay stations. Species number and density were negatively correlated with bottom water temperature, but they were positively correlated with both the bottom salinity and DO. The most dominant species in terms of density was a semelid bivalve, Theora fragilis which showed a positive correlation with TOC content of surface sediment and its high density occurred around Gogeum-Sinji-Joyakdo area where dense aquaculture facilities exist. In the bay mouth area, an amphipod species, Eriopisella sechellensis showed its higher density at the stations with low organic content but fine grains. The combination of water temperature, salinity, pH of bottom water, water and sulfur content of the surface sediment could explain 71% of the spatial distribution of macrobenthic fauna from the Bio-Env analysis. From the cluster analysis, the study area consisted of 6 distinct station groups lineated from offshore area toward inner area. Ampharete arctica, Goniada maculata, Eriopisella sechellensis, Theora fragilis, Caprella sp. were identified as the main contributing faunas in classification by the SIMPER analysis. From the value of BPI, the benthic communities at the inner and central Wando-Doam Bay were assessed to be in a normal condition whereas those at the outer Wando harbor and Gogeum-Sinji-Joyakdo area were assessed in a poor or very poor condition due to the high concentration of particulate organic matter might be originated from the nearby dense aquaculture facilities. This study indicated that pristine inner bay has been influenced by the organic material supplied from the outer bay. Thus it is necessary to establish an ecological management plan to reduce organic enrichment of sediment from dense aquaculture facilities in the outer bay.