• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.253-261
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• 1985

The reproduction of marbled sole Limanda yokohamae, caught near around the southeastern coast of Korea, from December 1983 to November 1984, was investigated based on such annual variations as gonadosomatic index(GSL), gametogenesis, reproductive cycle, spawning number, hepatosomatic index (HSI), and fatness. GSI began to increase in the autumn season with the onset of shorter day length and colder water temperature, and reached the maximum value in December with the shortest day length and the lowest temperature over the year. The gonad activated the proliferation of oogonia and spermatogonia in June, reached the mature stage in October, ripe in December, and spawning from the end of December to January. After spawning, it showed the resting stage which gonad remained regressive and suppressive from February to May. In addition, the adult individuals observed discharged eggs only once during their spawning period. At yolk globular stage, the substance of vitellogenin synthesized from the liver was considered to participate in the active yolk accumulation of oocytes. Marbled sole was concluded to be a typical winter spawning species in that such environmental factors as short day length and low water temperature were closely related with the gametogenesis, the stimulation of oocyte maturation, and were also affecting the ovulation.

• Journal of Wetlands Research
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• v.11 no.3
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• pp.49-59
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• 2009

Seasonal changes of the growth characteristics and biomass of Scirpus fluviatilis, a aquatic emergent vascular plant, were investigated to reveal the phenology and the population dynamics and to provide the fundamental resources for the restoration counterplan of the wetland vegetation in the littoral zone of the Upo wetland, Changnyeong-gun, Gyeongsangnam-do, Korea from March 2006 to November 2006. Scirpus fluviatilis was distributed commonly in Upo, Mokpo, Sajipo, Jokjibyeol, and Topyeongcheon upstream and downstream of Upo wetland, and the density was highest in Mokpo. Distribution range for the water depth was 9~49cm, and the highest shoot density in 26~49cm, and the mean shoot density was $119/m^2$, and the mean shoot length was 122.3cm on May 28. The number of the tuber was $104.5/0.25m^2$, and the living tubers were 84.2%. The mean fresh biomass of the living tubers was 3.0g, and those of 1~4g was most as 57.9%. Germination rates of the living tubers was 43.8%, and the maximum rate was in 7~9g and more than 10g. In the pot cultivation, the shoot density of the germinated tubers and the dormant tubers were highest as 13.5 and 9.7, respectively in early August. In the field study, the shoot density had few change before typhoon damage, while the density increased abruptly in November after flooding accompanied with the typhoon 'Ewiniar'. The shoot length in the pot cultivation and in the field study were 100~116cm and 60~170cm, respectively in the growth-end. Biomass allocation rates into the stem, leaf, flower, and underground parts were 8.9%, 6.6%, 0%, and 84.5%, respectively in the pot cultivation of the germinated tubers, and those of the dormant tubers were 7.1%, 7.1%, 0%, and 85.8%, respectively. The tuber number increased to 1.4~4.1 times by the growth-end, so it is concluded that Scirpus fluviatilis is mostly propagated by the vegetative reproduction.

• The Korean Journal of Ecology
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• v.12 no.3
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• pp.171-182
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• 1989

The structure, clonal grwoth, shoot modules dynamics and rhizome respiratory rate of the Phragmites longivalvis circular patch were studied in a 15-year-old reclaimed land on Mado of the western Korea for two growing seasons. Clonal growth by P. longivalvis resulted in subpopulations of shoot modules which may be separated into pioneer, mature and senile growth phase. The radial growth of circular patch was 208 cm per a year. The shoot phytomass, shoot height and spike frequency were the lowest in the senile phase, and were the highest in the mature phase. The maximum shoot phytomass of pioneer, mature and senile phase in August was 347, 536 and 195g/$\m^2$ for the first year, and 609, 748 and 248g/$\m^2$ for the second year, respectively. The birth rates of shoot modules were the highest during the early spring. Of all modules, the percemtage of spring cohort of pioneer, mature and senile growth phase were 52, 82 and 70% for the first year, and 83, 88 and 85% for the second year, respectively. The flowering shoots were only derived from spring cohorts. The death rates of shoot modules of the pioneer and mature phase were the highest in October. The module is an annual semelparous plant though the genet is a perennial iteroparous plant. Their survivorship curve was negatively (Deevey type I). The density of shoot modules of the pioneer, mature and senile growth phase increased as much as 4.0, 1.6 and 2.3 times for one year, respectively. The respiratory rate was the highest in the lowest in the senile growth phase.

• Korean Journal of Environmental Biology
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• v.24 no.2 s.62
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• pp.126-137
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• 2006

Effect of night-lights on zooplankton attraction has been studied in Tongyeong marine ranch area during the period from 12 July to 30 August, 2004. Each sampling has been carried out to collect zooplankton from both control area in natural waters experiment area of night-lights waters at night. A total of 43 taxa of zooplankton occurred during the study. Copepods showed the prosperity in species number with 15 species. Acartia erythraed and Copepodite occurred abundantly in night-lights waters. Zooplankton abundance appeared to increase in night-lights mainly due to the gathering of copepods and larvae through the study period. Average $3\sim166$ times of zooplankton abundance was recorded in night-lights when compared with that in control area of natural waters due to the gathering of copepods and larvae. Cluster analysis, based on monthly abundance data of the 13 most frequent species, showed that the species were seperated into two different groups: the photo-positive group and the photo-negative group.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.2
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• pp.98-106
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• 2005

Population dynamics in the vermicomposting bed was investigated. And harvesting efficiencies of earthworm attracting traps with different attractants, mesh sizes of net and covering materials was evaluated. Peak density of earthworm population was $5kg/m^2$ and therafter its desity kept $4.4{\sim}5.0kg/m^2$. It was evaluated that suitable mesh size of the net was 7mm and proper covering materials of the earthworm attracting trap was cotton quilt. The earthworm harvesting efficiency of trap with attractant was much higher than that of trap without attractant. With more amount of attractant in the trap and with longer setting period of trap onto the vermicomposting bed, the earthworm attracting trap harvested more earthworms. Crushed pear-peel attracted much more earthworms than paper mill sludge, but it was difficult to supply enough amount of crushed pear-peel for practical need. Sugar solution(10%) with tab water was proven to be an alternative to crushed pear-peel because its attracting effect on earthworm was as high as crushed pear-peel and it was easy to prepare and supply in large quantity.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.497-501
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• 2014

The small brown planthopper, Laodelphax striatellus (Fall$\acute{e}$n) (SBPH) is one of the important rice pests in Korea, which transmits rice stripe virus (RSV) to rice. This pest is an indigenous species in Korea and has also known to migrate from China to the western coastal areas of Korea. This study was conducted to investigate the wing morphs of SBPH and its parasitism rate of Haplogonatopus atratus Esaki et Hashimoto in Korea. In 2014, SBPH were collected in April and July from 16 sites throughout South Korea and their wing morphs and parasitism rates were measured under the microscope. Percentage of brachypterous male in July was significantly declined compared to that in April, while that of brachypterous female did not change. A positive relationship was found between latitude and percentage of brachypterous adults in April. Parasitism rate of both nymphs and adults were higher in April than July. In addition, nymphal parasitism rate was generally higher in western coastal areas.

• ALGAE
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• v.23 no.3
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• pp.241-250
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• 2008

Since seagrasses in the coastal and estuarine ecosystems achieve high levels of production, they require high inorganic carbon and nutrient incorporation. Thus, seagrasses may play a significant role in carbon and nutrient cycling in the coastal and estuarine ecosystems. To examine growth dynamics of Zostera marina L. environmental factors such as underwater irradiance, water temperature, and salinity, and biological parameters such as shoot density, biomass, shoot morphology, and leaf productivity were measured in two bay systems (Jindong Bay and Gamak Bay) on the southern coast of Korea. While underwater irradiance did not show distinct seasonal trend, water temperature at both sites exhibited clear seasonal trend throughout the experimental period. Shoot density increased dramatically during winter due to the increased seedlings through germination of seeds in Jindong Bay and due to the increased lateral shoots in Gamak Bay. Eelgrass biomass increased during winter and decreased during summer. Maximum biomass in Jindong Bay and Gamak Bay was 250.2 and 232.3 g dry weight m–a2, respectively. Carbon incorporation into the eelgrass leaf tissues was estimated from productivity and leaf tissues carbon content. The calculated annual carbon incorporations at the Jindong Bay and Gamak Bay sites were 163 and 295 g C m–`2 y–`1, respectively. This high carbon incorporation into seagrass tissues suggests that seagrass habitats play an important role as a carbon absorber in the coastal and estuarine ecosystems.

• The Korean Journal of Ecology
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• v.21 no.1
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• pp.27-33
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• 1998

Arisaema robustum, which has the ability to change sex, was studied in a temperate broadleaf forest of Sanseong-ri, Joongbu-myeon, Gwangju-gun, Kyonggi Province, Korea. \ulcornerThe study, carried out from 1993 to 1997, focused on population dynamics energy budget among organs, size distribution, mortality, the relationships between sex and size, seed production and germination rate. In terms of energy budget among the organs, the ratio of aboveground to belowground biomass was 36.6 : 63.4 in non-female plants, and 81.4 : 18.6 in female plants. Also, in female plants, the ration of leaf to sexual organ biomass was 39.5 : 41.9. Therefore, the belowground ratio of female plants was lower than that of non-female plants. Plants were classified into 8 levels relative to the amount of leaf area by $100cm^2$. The rates of the smallest and the largest classes were 49% and 1%, respectively, and population distribution by size was relatively stable. The mortality averaged 13.1% per year and decreased in inverse proportion to leaf size (6.6% in the smallest and 0.0% in the largest size classes). Leaf areas were $64.1{\pm}48.5cm^2$ in non-flowering plants, $232.1{\pm}123.9cm^2$ in males and $444.8{\pm}153.9cm^2$ in females. The increase rates of leaf area per year varied from 1.9% in plants changing from female tomale, to 152.4% in plants changing from non-flowering to female. But plants which remained female for 2 years showed a decrease of 34.7%. >From this result, it is thought that the female plants invest more energy to reproduction than to vegetative organs. The correlation coefficient (CC) value between plant size and the number of seeds produced (0.55) was larger than the CC value between plant size and total seed weight (0.73). That is, the larger the plant size, the heavier the seed produced. The germination rate increased along with seed weight, and it was 95% in plants which were over 60mg fresh weight/seed.

• Korean Journal of Environment and Ecology
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• v.20 no.2
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• pp.81-93
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• 2006

To investigate distribution status of the evergreen broad-leaves forest in Weolchulsan National Park, 146 plots and surveyed. Thirteen Evergreen broad-leaved trees wear distributed up to four hundred fifty meters(sea level) along valley in the Weolchulsan National Park. Camellia japonica, Eurya japonica and Quercus acuta were distributed as a plant community. Neolitsea sericea, Vaccinium bracteatum, Camellia sinensis, Eleagnus macrophylla, Ligustrum japonicum and Ardisia japonica were distributed as small patch or individual. Trachelospermum asiaticum and Hedera japonica were distributed by discoid, erysipelas shape. Quercus acuta community was appeared as a small patch type in Weolchulsan National Park. Evergreen broad-leaved trees were distributed at subcanopy layer in the Pinus densiflora community, Quercus varabilis community and Quercus acutissima community. Quercus acuta community might be maintained and expanded. Pinus densiflora community and deciduous broad-leaved plant community at which Quercus acuta, were growing in the forest floor will be succeeded to Quercus acuta community.