• ALGAE
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• v.30 no.2
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• pp.139-146
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• 2015

Urchin barrens have been a major issue of rocky coastal ecosystems in temperate regions. In South Korea, the east coast and Jeju Island have especially been a focus because the area of barren ground increases in spite of continual efforts to install artificial reefs. This study approached the urchin barrens issue in South Korea, by focusing on a correlational analysis of urchin and macroalgal abundance. Urchin density and algal species coverage were obtained using a quadrat image analysis. Subtidal sites were then classified into three groups according to the average densities of urchins to evaluate the characterization of the macroalgal community: no urchin (NU) zone; transition (TR) zone, $4inds.\;m^{-2};$ and urchin (UR) zone, ${\geq}8inds.\;m^{-2}$. The average urchin density in the study site was $4.7inds.\;m^{-2}$ and 57 macroalgal species were found in the study site. From the NU zone to UR zone, total species number, species diversity index and evenness gradually decreased, whereas the dominance index increased. The algae species with negative correlations were Grateloupia divaricata, Polysiphonia morrowii, Chondracanthus intermedius, Delesseria violacea, Desmarestia viridis; and those with positive correlations were the crustose corallines, Sargassum horneri. Other species were not significantly correlated with urchin density. The significant correlations indicate that the abundance of some macroalgal species is proportionally regulated by sea urchin density. This study also shows how macroalgal vegetation changes in response to an urchin's density gradient in a natural condition; and there is a TR zone that existed with respect to an intermediate level of algal abundance.

• Korean Journal of Organic Agriculture
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• v.17 no.2
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• pp.193-209
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• 2009

Total collected benthic macro invertebrates in rice paddy fields were identified 3 phylum, 5 class, 13 order, 25 family, 32 genera and 36 species, those in organic rice field were 12 order, 22 family and 28 species, and in conventional rice field were 10 order, 19 family and 25 species. The almost collected species inhabit lentic zone but Semisulcospira libertina, Corbicula fluminea, and Tipula sp. were habitat on lotic zone. The number of benthic macro invertebrates species was higher in organic paddy field than in conventional field. Eleven species were collected only on organic but eight species only on conventional field. The number of individuals were 870 on organic rice field which higher 3.6-fold on conventional field. The diversity indices of organic rice field were 1.57-2.45 and 0.71-2.61 in the first and second survey, respectively. The higher diversity indices, the lower dominance indices.

• Journal of Ecology and Environment
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• v.34 no.4
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• pp.381-391
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• 2011

Many lichens have been used as bioindicators for air pollutants such as $SO_2$. The first ecological study on lichens in Korea was conducted in 1975 by Kim and Lee, disclosing that areas adjacent to the center of Seoul were lichen deserts. Air quality in Seoul has improved significantly since the 1980s. However, the distribution of lichen species has not been reevaluated since then. We examined the spatial and temporal pattern of lichen distribution by selecting six (inner city green [ICG] and four (outer city green [OCG]) sites, based on the distance from the city center of Seoul and the land use pattern. The change in lichen distribution was related to yearly mean concentrations of $SO_2$, $NO_2$, and $O_3$ for the years 1980-2009. Four and 13 lichen species were found in ICGs and OCGs, respectively. Although mean sample numbers per species were much higher in the former, species richness tended to increase with distance from the city center. Since 1980, $SO_2$ has declined drastically to < 0.01 ppm in both ICGs and OCGs, indicating that $SO_2$ is no longer a limiting factor for lichen establishment and growth. In contrast, $NO_2$ has increased steadily for 20 years (1989-2009) and a considerable proportion of lichen species in both ICGs and OCGs are known as nitrophilic or pollution-tolerant species. Appearance of nitrophiles in both ICGs and OCGs and the dominance of a few lichen species in ICGs may reflect the effects of the increase in $NO_2$. In contrast to $SO_2$ and $NO_2$, $O_3$ was higher in OCGs, but it was difficult to identify a causal relationship between $O_3$ and lichen distribution.

• The Korean Journal of Ecology
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• v.24 no.4
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• pp.233-237
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• 2001

Changes of the oribatid mite species composition during the litter decomposition was investigated in the north-facing and south-facing slopes with different lower vegetation (annual herbaceous plants in north and perennial Sasa in south) in the altitude 1,000 m of Mt. Jumbong, a nature reserve area in Korea, from August 1994 to September 1995. Total 58 species of oribatid mites were collected. The values of O1son's negative exponential index (k) were -0.56 in the south-facing slope and -0.49 in the north-facing slope, but there was no significant difference between them. The decomposition rate of litter increased rapidly until Oct. 1994, and decreased thereafter. Intensive settlement of the forest litter by oribatid mites was recorded in the autumn periods and it decreased in the next spring and summer. Species diversity index (H'), and species evenness (J') ranged from 1.74 to 2.69, and from 0.57 to 0.93, respectively, and the values were lowest in spring. In the successive periods of growing season, there followed great changes in the structure of species dominance. Heminothrus minor was one of the most dominant species in autumn in the first year when litter were placed, but was never recovered next seasons. In contrast, Platynothrus yamasakii was also dominant in the first autumn, then decreased very low in numbers in next spring and summer, but regained its number in autumn. On the other hand, an increase of the number during these periods was observed by Epidamaeus sp.2. Ceratopia bipilis and Epidamaeus sp.1 were abundant both in the north-and south-facing slopes. Trichogalumna nipponica was only found in the south-facing slope, and Nanhermannia elegantula was only found in the north-facing slope.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.3
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• pp.243-251
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• 2019

The ichthyoplanktons were sampled by Bongo net to study the distribution of the eggs and larvae in the West coastal waters of Korea during the study period (February, May, August and October of 2017). Collected fish eggs were divided into Engraulis japonicus and unidentified species. The most dominant species, Engraulis japonicus accounted for 79.52% of the total fish egg, which was followed by unidentified species (20.48%). The total of 36 taxa in fish larvae were identified based on morphological and molecular characteristics. Fish larvae were dominant by Gobiidae species. 48.30% of the total catch in abundance, which was followed by Engraulis japonicus (31.86%). These two taxa composed 80.16% of the total collected fish larvae. The seasonal diversity index of species from the collected fish larvae in the West coastal waters in 2017 was 0.625-1.883 and the evenness index was 0.380-0.865. In addition, dominance index was 0.618-0.920 and richness was 0.573-3.189.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.1
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• pp.13-22
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• 2022

In this study, we investigated the water quality and fish community of the Gudam Wetland, a riverine wetland in the middle-upper reaches of the Nakdong River, during March-October 2020. The main results were as follows: average annual flow rate: 45.0±23.7 m³/s, flow velocity: 0.4±0.3 m/s, water depth: 1.4±0.4 m, water temperature: 17.5±0.8℃, pH: 7.8±0.2, electrical conductivity: 121.6±19.0 ㎲/cm, dissolved oxygen concentration: 11.4±0.9 mg/L, suspended solids concentration: 3.8±2.0 mg/L, and the water quality was classified as Ia (very good). A total of 754 individual fish belonging to 4 orders, 7 families, and 19 species were investigated. Cyprinidae was the dominant group, with 13 species. The dominant species was Zacco platypus (39.3%), followed by Pseudogobio esocinus (17.5%). There were 8 (42.1%) endemic Korean species and 1 exotic species, Micropterus salmoides. Four species were carnivores, six were insectivores, and nine were omnivores. Regarding tolerance to environmental changes, 6 species were tolerant, 11 had intermediate tolerance, and 2 were sensitive. Fish community analysis revealed dominance of 0.57, diversity of 2.04, evenness of 0.69, and richness of 2.72, indicating a diverse and stable fish community. The fish assessment index showed that the assessment class was B (average 62.5), which was higher than that of major streams of the Nakdong River (class C). For sustainable conservation of the Gudam Wetland, management strategies such as minimizing aggregate collection and preventing inflow of non-point pollutants are required.

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.331-341
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• 2014

The present study was to survey the site environment, vegetation structure and soil characteristics in the wild habitats of Wikstroemia ganpi in Goheung, Busan and Ulsan, and offers basic information for habitat conservation and restoration. Most of the wild habitats were located at altitudes between 28~242m with inclinations ranged as $0{\sim}40^{\circ}$. The canopy openness was 57.56%. The vegetation structure by the PC-ORD based on the Two Way Cluster Analysis were divided into three groups Community I(Castanea crenata-Pinus densiflora), Community II(Quercus dentata-Pinus thunbergii) and Community III (Pinus thunbergii). The species diversity was 1.3650, and evenness and dominance were found recorded as 0.8666 and 0.1333, respectively. The soil textures were silty loam and sandy loam. The average soil pH was 5.5, electric conductivity was 0.15dS/m, soil organic matter was 2.60% and available phosphorus was 4mg $kg^{-1}$. Correlation coefficients based on environmental factors, vegetation and soil analysis were showed that positive correlations between species diversity and evenness, organic matter and total nitrogen, whereas species slop degree and coverage of herb, diversity and dominance were showed negative correlations.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.607-618
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• 2013

Marine macroalgal community structures and characteristics of ocean environmental factors were examined seasonally at four sites in Jeju Island, Korea, from March to November 2012. A total of 71 macroalgal species were identified, including 9 green, 7 brown, and 55 red algae. Peyssonnelia capensis occurred at all study sites and in all seasons. The average annual biomass of seaweed was 991.84 g wet $wt/m^2$, with seasonal variations from 543.80 g in autumn to 1,284.17 $g/m^2$ in summer. A green alga, Codium coactum, was the dominant species, occupying 21.31% (211.39 $g/m^2$) of the total algal biomass in Jeju Island. Subdominant species were Ecklonia cava and Lithophyllum okamurae, comprising 20.85% (206.75 $g/m^2$) and 19.64% (194.75 $g/m^2$), respectively, of the total algal biomass in Jeju Island. The vertical distribution of subtidal seaweeds was represented by L. okamurae at 5 m depth, C. coactum at 10 m depth, E. cava at 5-10 m depth and P. capensis at the 20 m depth level. In the present study, crustose coralline algae, which predominated on barren ground, were subdominant species at all study sites. Community indices varied between 0.51-0.63 for dominance index (DI), 5.53-8.14 for richness index (R), 0.51-0.63 for evenness index (J'), and 2.04-2.32 for diversity index (H'). On the basis of seaweed biomass and community indices, Sinchang was the best preserved coastal area, showing maximal values in biomass, and evenness- and diversity-indices, and minimal value in the dominance index, representing stable environmental conditions. In contrast, the Onpyung and Topyeong sites, located near tourist venues such as Udo and Seogwipo were relatively poor habitats based on community indices and biomass. The present results could imply that climate changes alter seaweed community structure, and long-term monitoring of the study sites is required.

• Journal of Korean Society of Forest Science
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• v.101 no.4
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• pp.579-591
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• 2012

Berchemia berchemiaefolia is a rare and endangered species and important as a honey resource. The purposes of this study were to investigate physical environmental factors and the population and community structure of Berchemia berchemiaefolia stands at Mt. Gunja in Sogrisan National Park in Chungcheongbuk-do. The B. berchemiaefolia stands belonged to deciduous forests in mid-temperate zone and were $5{\sim}25^{\circ}$ in slope, 30~90% in rock ratio, and 6.37 in soil pH. They had 656 trees within the area of 36 ha and their average density was 18.2 trees per ha. The trees within the stands were 11.8 m in tree height, 22.6 cm in DBH and 56 years old. The number of branched stems was the maximum 8 and 32.9% of the trees were branched. B. berchemiaefolia trees over 12 cm diameter occupied 89.9%, but young B. berchemiaefolia did only 11%. The structure of B. berchemiaefolia stands were classified into three groups as Acer pseudo-sieboldianum & A. mono community group, A. pseudo-sieboldianum & Quercus aliena community group, and B. berchemiaefolia & Quercus serata community group. The mean importance value of B. berchemiaefolia was 10.9%, while species diversity of the community ranged 0.77~1.31 and interspecific competition ranged 0.78~0.94. The dominance of the community ranged of 0.07~0.29 and the evenness ranged 0.71~0.93. Although B. berchemiaefolia was dominant in the habitat, but the species was already in natural successional stage to Cornus controversa or Ulmus davidiana var. japonica.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.95-103
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• 2015

In this study, we surveyed the distribution pattern and dominance of weeds occurred in four summer crop fields, hot pepper, soybean, maize, and Chinese cabbage in Gyeongbuk province. The weeds were summarized as 32 family and 132 species in hot pepper field, 31 family and 116 species in soybean field, 37 family 134 species in maize field, finally 35 family and 170 species in Chinese cabbage field. Among these weeds occurred in the four summer crop fields, the compositae was commonly dominant family, it occupied 17.4% in hot pepper field, 18.1% in soybean field, 11.9% in maize field, and 16.5% in Chinese cabbage field. The major five families including compositatae, graminae, polygonaceae, convolvulaceae and cruciferae were occupied 43.2% in hot pepper field, 47.4% in soybean field, 42.5% in maize field, and 43.5% in Chinese cabbage field, respectively. Furthermore, the most dominant weed in the hot pepper, soybean, maize, and Chinese cabbage fields was Portulaca oleracea, Digitaria ciliaris, and Rorippa palustris, respectively. This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in food crop fields of Gyeongbuk province.