• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.2
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• pp.87-102
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• 2022

To clarify the spatial distribution pattern of macrozoobenthos in Korean coastal waters in the summer season and investigate the relationship between community structure and benthic environmental factors, field surveys on community structure and benthic environmental factors were conducted at 117 stations in August 2017. A total of 613 macrobenthic species were identified, with the mean density of 1,228 ind./m² and the mean biomass (wet weight) of 110.9 g WW/m². Rich biodiversity was found at stations near Wando and along the coast of the East Sea, and there is a trend that stations with greater biodiversity also showed higher mean density as well. The dominant species in all the coastal areas in Korea was Heteromastus filiformis, which were found at most of the stations during the survey. The relatively deep areas in the East Sea were dominated by Magelona johnsoni and Maldane cristata, which were the third and ninth dominant species in the study areas, respectively. Pseudopolydora kempi and Rhynchospio sp. were observed only at the station located in the Nakdong River estuary. From the cluster analysis the stations could be clustered into three station groups with more similar faunal composition. Group A was located in the eastern coast, characterized with deep water depth and low levels of sand contents, while Group B was located in the southern coast, characterized by shallow depth of water and high content of mud and organic matter. Lastly, Group C was in the western coast, demonstrating low levels of mud content and organic matters. The biodiversity of macrobenthic species in the study area showed high positive correlation coefficients with benthic environmental factors such as sorting, clay, silt, and contents of organic matter in sediments, but negatively correlated with the sand contents. Major dominant species, Theora lata and Eriopisella sechellensis, both showed negative correlation coefficients with the sand contents, but a relatively high positive correlation with the levels of organic contents.It can be concluded that the spatial distribution patterns of macrobenthic organisms in Korean coastal waters are affected by depth, sediment type, and contents of organic matters.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.284-291
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• 2014

We surveyed the distribution of exotic weeds in the 350 upland crop fields of Gyeonggi-do. The exotic weeds were summarized as 78 taxa including 19 families, 52 genera, 74 species and 4 varieties. Among the total exotic weeds, the summer annuals were 48.7%, the winter annuals 28.2%, and the perennials 23.1%. Compositae was dominant family (32%), followed by Gramineae (8%), Polygonaceae (8%) and Malvaceae (7%). Dominant exotic weeds in northern Gyeonggi-do were Amaranthus lividus, Ambrosia trifida, Chenopodium album, Bidens frondosa and Erigeron Canadensis, and in southern Gyeonggi-do were Chenopodium album, Erigeron Canadensis, Erigeron annuus, Taraxacum officinale and Galinsoga ciliate. The most dominant exotic weeds in the Gyeonggi-do were Chenopodium album, followed by Amaranthus blitum, Erigeron canadensis. Canonical correspondence analysis for investigation of correlation between exotic weeds occurred in northern and southern Gyeonggi-do showed that the exotic weeds in northern Gyeonggi-do were more diverse then in southern Gyeonggi-do. This information could be useful for establishment of exotic weed control methods in Gyeonggi-do.

• Korean Journal of Environment and Ecology
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• v.25 no.2
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• pp.123-131
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• 2011

Seabird distribution in the East Sea was studied from April to May 2007 using line transect counts. We observed a total of 1,379 individuals of 23 species including 14 species of seabird. The overall seabird sighting rate was 2.5 birds $km^{-2}$. The Streaked shearwater(Calonectris leucomelas)(74.5%) was the numerically dominant species. Ancient murrelets(Synthliboramphus antiquus)(8.3%), red-throated divers(Gavia stellata)(5.0%), common terns(Sterna hirundo)(2.1%), Pacific divers(Gavia pacifica)(2.0%), and black-tailed gulls (Larus crassirostris)(1.1%) were also frequently observed. The sightings of seabirds was highest between $36^{\circ}N$ and $37^{\circ}N$ of the coastal area of the Korean peninsular. However, the index of species diversity(H') was higher between $35^{\circ}N$ and $36^{\circ}N$. The sighting rates of most observed species decreased with distance from the coastline. The distribution patterns of Streaked shearwater were linked to the variation in the distribution pattern of minke whales(Balaenoptera acutorostrata). Also, spatial segregation was found in the distributions of the two species of divers(Gavia spp.).

• Korean journal of applied entomology
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• v.39 no.1
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• pp.31-41
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• 2000

Community analysis of oribatid mites was conducted in Namsan and Kwangreung coniferous forests which have been received by different degrees of environmental pressures through urbanization processes. Oribatid mites were sampled in the litter and soil layer of study sites from May 1993 to October 1994. Although two sites have been under similar weather condition, seasonal changes in oribatid mites density did not show a synchronized pattern. Density in spring and summer showed stable pattern with low fluctuations, but unstable pattern in autumn between 1993 and 1994. And these patterns were highly correlated with precipitation. The density and species number were higher in the litter layer than in the soil layer and showed no typical seasonal changes. The dominant species were Scheloribates latipes (1 l.78%), Pergalumna altera (8.92%), Eohypochthonius crassisetiger (7.58%), Scheloribates sp. (6.89%) and Suctobelbella yezoensis (5.04%) in Namsan, and Ceratozetes japonicus (25.72%), Punctoribates punctum (14.15%), Trichogalumna nipponica (10.96%) and Ramusella sengbuschi (5.08%) in Kwangreung. The number of species with high constany were 10 and 18 in Namsan and Kwangreung, respectively. Namsan showed the feature of urban forests. In analysis of species diversity, species richness was significantly higher in Kwangreung than in Namsan, while shannon (H') and evenness index (J') were higher in Namsan than in Kwangreung. The values of shannon index (H') in Namsan and Kwangreugn were 2.83 and 2.62, respectively and evenness index (J') were 0.78 and 0.67, respectively. The value of similarity index between two sites was 0.68.

• Korean Journal of Environment and Ecology
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• v.24 no.6
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• pp.648-656
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• 2010

Global warming brings changes of natural ecosystems and affects on the plant growth response. Quercus acutissima and Q. variabilis are taxonomically similar and dominant native species in deciduous forests in South Korea. In order to understand the growth response of Q. acutissima and Q. variabilis to global warming condition, we cultivated the seedling of the two oak species in ambient condition(control) and treatment with elevated $CO_2$(700~800ppm) and increased air temperature(approximately $3^{\circ}C$ above than control). Then we measured the growth characteristic among them and analyzed the relationship between two species using PCA ordination. Stem length and total plant weight of Q. acutissima were significantly affected by elevated $CO_2$ concentration and increased air temperature. Stem diameter and weight of Q. variabilis were significantly affected by elevated $CO_2$ concentration and increased air temperature(p<0.05). The variation characteristics of Q. acutissima were changed more than Q. variabilis by elevated $CO_2$ concentration and increased air temperature. These result suggested that Q. acutissima was more sensitive to global warming situation than Q. variabilis in central region of Korea. PCA ordination showed that two species were arranged by two distinct groups based on 10 characters by elevated $CO_2$ and increased air temperature.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.497-506
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• 2010

This study intended to investigate the environmental factors including soil and vegetation in order to better understand the environmental and ecological characteristics of ten different habitats of $Hanabusaya$ $asiatica$. These habitats, according to investigations, are mostly located on the slopes of mountains facing north at an altitude of 580 m to 1,396 m above sea level with angles of inclination ranging from 5 degrees to 80 degrees. A total of 146 vascular plant taxa are identified in 32 quadrates of the ten habitats. The importance value of $H.$ $asiatica$ is 8.87%, and 5 highly ranked species such as $Carex$ $siderosticta$ (8.67%), $Ainsliaea$ $acerifolia$ var. $subapoda$ (7.10%), $Calamagrostis$ $arundinacea$ (6.79%), $Athyrium$ $yokoscense$ (5.33%), $Astilbe$ $rubra$ (3.11%) are considered to be an affinity with $H.$ $asiatica$ in their habitats. Dominant species of woody plants in ten habitats are represented as $Quercus$ $mongolica$ in tree layer (T1), $Acer$ $pseudo$-$sieboldianum$ in subtree layer (T2), $Rhododendron$ $schlippenbachii$ and $Tripterygium$ $regelii$ in shrub layer (S). The degree of their average species diversity is 1.30, and that of dominance and evenness are 0.08 and 0.88, respectively. The type of soil is sandy loam, loam and loamy sand, and the average field capacity of soil is 23.95%. Their average organic matter is 12.28%, soil pH 5.79, and available phosphorus is 25.48%. Correlation coefficients analysis based on environmental factors, vegetation and soil analysis shows that the coverage of tree layers is correlated with richness, diversity, dominance, evenness and coverage of $H.$ $asiatica$.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.468-480
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• 2007

The urbanization is altering the hydrology, water quality, channel form of waterway and changing the composition of biological communities in the aquatic ecosystem. Recently, towns grew bigger by the drift of large numbers of people and the medium and small leather and dyeing industries around the Pocheon and Youngpyeong streams. The discharges of sewage were increased by them. The UII (urban intensity index) was 85 (st. P-3) and 91 (st. P-6) in the Pocheon stream and about 20 in the Youngpyeong stream. A total 141 taxa of epilithic diatoms which were composed of 2 order, 8 family, 30 genera. Dominant species were Navicula saprophila, N. subminuscula, Nitzschia palea, Gomphonema pseudoaugur in the Pocheon stream and Achnanthes alteragracillima, A. convergens, A. minutissima, N. minima, N. fonticola, N. frustulum and Cymbella minuta var. silesiaca in the Youngpyeong stream. It Showed the different composition of dominant species by the urbanization near two streams. In the relationships between UII and environmental factors such as EC, BOD, COD, TN, TP and DAIpo, UII showed the high relations $(r^2>0.8)$. It was the difference of organic pollution according to urbanization. It therefore, was higher the relative abundance and more the numbers of saprophilous taxa in the Pocheon stream than the Youngpyeong stream. The water quality of two streams by biological indicators(DAIpo) was polysaprobic state(st. P-3, P-4, P-5) in the Pocheon stream and was oligosaprobic (Y-1), mesosaprobic (Y-2, 3) and polysaprobic state (Y-4) in the Youngpyeong stream during the investigation periods.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.354-366
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• 2022

To analyze the distribution of plant communities growing in river wetlands and the relationship between biotic and abiotic environmental factors, plant communities and environmental factors were investigated in river wetlands in the Boseong River. The Boseong River Wetland, the research site, consists of Hwapyeong Wetland, Bangujeong Wetland, and Seokgok Wetland. From June to September 2022, a plant community survey was conducted from the perspective of physiognomical vegetation, and the coverage of the emerging species followed the Braun-Blanquet scale. Plant species and the coverage of each species were recorded in the quadrant for plant community survey, and the cover of the quadrant, the total number of species, and the number of exotic species were measured as biological factors. As abiotic factors, altitude, orientation, inclination, soil texture, litter layer depth, dominant species diameter at breast height, and topography were recorded. In a total of 50 square plots, the most common Salix koreensis and Phragmites japonicus communities were found, and the community with the highest Shannon species diversity index was Phragmites japonicus-Echinochloa caudata community. As a result of ordination analysis by DCCA, the most significant clusters were separated according to topographic factors such as leeve, leeve slope, upper floodplain, lower floodplain, upper waterside, middle waterside, lower waterside, river island and opem water. As rare plants that need to be preserved in river wetlands, Hydrocharis dubia and Penthorum chinense were found in lower waterside, and it was found that the management of the river in the reservoir is necessary in line with the topographical distribution of ecosystem-disrupting plants, such as Paspalum distichum var. indutum.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.1
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• pp.1-10
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• 2006

Previous studies on zooplankton in Asan Bay were mostly based on samples collected seasonally with three months intervals. Present study was aimed to know the temporal variation of meso-zooplankton distribution using the data collected monthly. Relationships between zooplankton abundances and environmental factors such as seawater temperatures, salinities and chlorophyll-a contents were also studied. Seawater temperature showed typical pattern of seasonal variation found in temperate waters. The fluctuations of environmental factors ranged relatively wider In the inner part of the bay than those in outer part of the bay. Salinity was very low right after the summer rainy period due to the sporadic outflow of freshwater from the adjacent artificial lakes. Sudden changes in salinity seemed to have significant impact on zooplankton assemblages. Chlorophyll-a contents were increased in general when compared with previous reports probably due to the recent human exploitations in the coastal zone, which might enhance the nutrients level . The timing and duration of spring bloom showed geographical differences. In the inner part of the bay it began earlier (February) and last longer (three months) while in the outer part of the bay it began late (April) and last just one month. Zooplankton abundance, especially most abundant taxon Acartia hongi, showed weak but significant positive correlation with chlorophyll-a contents. The difference in temporal variation found with two different sampling intervals indicated the necessity of shorter time interval samplings.

• Korean Journal of Environmental Biology
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• v.42 no.1
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• pp.15-27
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• 2024

The goal of this study was to provide basic data necessary for managing fish in the Seomgang River by confirming diversity of fish species in the Seomgang River and determining the degree of change in fish species through a comparison with earlier related work. Growth rate, obesity level, and temporal and spatial reproductive capacities were analyzed to determine growth characteristics of dominant species. Fish fauna and structure of the fish community were surveyed at three different time points from October of 2020 to August of 2021 at eight sites. In addition, growth characteristics of Zacco platypus from June of 2021 to July of 2022 at four sites were determined. A total of 3,999 individuals, 43 species, and ten families of fish were identified. Among these species, 19 (44.19%) were Korean endemic species and four (9.30%) were endangered species. The dominant species was Z. platypus. Pungtungia herzi was identified as a subdominant species. An analysis of length-weight relationships and condition factor (k) of Z. platypus confirmed a good state of growth. As a result of a frequency analysis of the total length, the life cycle of the Z. platypus population living in the Seomgang River was found to be stable. According to gonadosomatic index (GSI) analysis, the spawning season of Z. platypus was estimated to occur after May, consistent with the literature.