• 한국발생생물학회지:발생과생식
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• 제22권4호
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• pp.361-367
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• 2018

The newborn, Hippocampus kuda larvae were 6.97-8.81, standard length (SL) mm (mean 7.89 mm) and mouth and anuse were open. Dorsal fin rays 15-18 and pectoral fin-rays were counted 8 and had 10-11+21 myotomes, body's bony plate ring being developed strongly in the central axis of myotomes part. 4 days after bearing, the SL was 7.02-9.47 mm (mean 8.24 mm) and nostrils began to open. 12 days after bearing, larvae attained to 8.91-11.2 SL mm (mean 10.0 mm). From this time, their unique predation habit appeared. 21 days bearing, larvae attained to 12.1-14.8 SL mm (mean 13.4 mm) the and thorn of back was enlarged among the plate formed around ring. 41 days bearing, seahorses attained to 17.1-17.8 SL mm (mean 17.4 mm) and the number of body's bony plate ring of the top of rings trunk was 11 and on the tail of them was 33-36, similar to figure of adult.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제4권1호
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• pp.1-8
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• 2023

In this study, we aimed to quantify the population size and spatial distribution of three predatory Scarites species in coastal sand dunes. In June and August 2014, 252 pitfall traps were utilized to conduct a trapping web analysis at three distinct sites with varying vegetation dominance values. Scarites sulcatus had the largest estimated population in a 10 m² area with a habitat density of 36.6 in a Vitex rotundifolia community area (site B) in the June survey. In contrast, Scarites aterrimus had the largest population size with a habitat density of 2.9 in a Calystegia soldanella community area (site A) in the August survey. Spatial distribution analysis revealed that S. sulcatus dominated the Vitex rotundifolia community without preference for a particular site, whereas S. aterrimus and Scarites terricola pacificus were primarily observed on the beach. The results indicated that the three Scarites species in the Sohwang coastal sand dune region exhibited differences in their spatial and temporal distributions in the coastal dune ecosystem in order to avoid competition and predation. In conclusion, our findings can be utilized to estimate the population density of the genus Scarites on the Korean Peninsula. The outcomes of this study will contribute to estimating insect population densities on the Korean Peninsula and developing investigative assessment methodologies.

• 생태와환경
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• 제41권4호
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• pp.431-440
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• 2008

Turbid water or suspended sediment is associated with negative effects on aquatic organisms; fish, aquatic invertebrate, and periphyton. Effects of turbid water on fish differ depending on their developmental stage and a level of turbidity. Low turbid water may cause feeding and predation rates, reaction distance, and avoidance in fish, and it could make fish to die under high turbidity and long period. Therefore, it is very important to find out how turbid water or suspended sediment can affect fish in domestic watersheds. The objectives of this study were 1) to introduce international case studies and their standards to deal with suspended sediment, 2) to determine acute toxicity in 4 major freshwater fishes, and 3) to determine in relation to adverse effect of macroinvertebrates and fish. Impacts of turbid water on fish can be categorized into direct and indirect effects, and some factors such as duration and frequency of exposure, toxicity, temperature, life stage of fish, size of particle, time of occurrence, availability of and access to refugia, etc, play important role to decide magnitude of effect. A review of turbidity standard in USA, Canada, and Europe indicated that each standard varied with natural condition, and Alaska allowed liberal increase of turbidity over natural conditions in streams. Even though acute toxicity with four different species did not show any fatal effect, it should be considered to conduct a chronic test (long-term) for more detailed assessment. Compared to the control, dominance index of macroinvertebrates was greater in the turbid site, whereas biotic index, species diversity index, species richness index, and ecological score were smaller in the turbid site. According to histopathological analysis with gills of macroinvertebrate and fishes, morphological and physiological modification of gills due to suspended sediments can cause disturbance of respiration, excretion and secretion. In conclusion, in order to maintain good and healthy aquatic ecosystem, it is the best to minimize or prevent impact by occurrence of turbid water in stream and reservoir. We must make every effort to maintain and manage healthy aquatic ecosystem with additional investigation using various assessment tools and periodic biomonitoring of fish.

• 한국응용곤충학회지
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• 제42권3호
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• pp.197-201
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• 2003

포식성 천적 O. kashmiricabenefica의 식식성 응애류 3종에 대한 포식량, 포식선호성 그리고 동족포식을 조사하였다. 성충의 일평균포식량은 먹이인 응애의 밀도와 온도가 높을수록 증가하였다. $25^{\circ}C$ 항온조건하에서 O. kashmirica benefica 성충의 일평균포식량은 귤응애, 점박이응애, 차응애 성충을 각각 21.9, 13.5, 14.1마리씩 포식하였다. 유충의 포식량은 영기가 증가할수록 많아져서, 1령, 2령, 3령 유충이 각각 2.8, 11.2, 25.4마리의 귤응애 성충을 포식하였다. O. kashmirica benefica 유충은 귤응애, 점박이응애, 차응애 성충을 유충기간(5일, $25^{\circ}C$)동안 각각 77.7, 61.3, 73.0마리씩 포식하였다. O. kashmirica benefica 유충과 성충은 글응애, 점박이응애, 차응애 중에서 특정한 종을 선호하는 경향은 없었으며, 먹이가 없을 때에도 동족포식 정도는 매우 낮았다.

• The Korean Journal of Ecology
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• 제24권6호
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• pp.377-380
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• 2001

Herbivory is an important selective forces on plants by reducing the ability of the plant to compete with its neighbors and to produce offspring. Oak nut weevil(Mechoris ursulus Roelofs) females lay eggs in unmatured acorns and cut off the branch of oviposited acorns. To investigate the influences of branch-cutting behavior of oak nut weevils on oak production, we surveyed the horizontal and vertical distribution ranges of damaged oaks and depth of sites of overwintering larvae and quantified the amounts of biomass and acorn removed by the weevils on deciduous oak species. All of the endemic oak species in Korea were damaged by oak nut weevils in all of the study sites including Mt. Halla and Mt. Seorak. The upper limit of vertical distribution of damaged oaks by the weevils raried from 700 m to 900 m. Mostly their larvae were found in soil from 8.1 cm to 10.0 cm depth in winter. Percentage of annual net primary productivity($720g{\cdot}m^{-2}{\cdot}day^{-1}$) of oak species removed by the weevils was about 7%, which is higher than the percentage removed by all the herbivores in typical temperate forest(5%) and equivalent to that by all the herbivores in tropical forest. The predation percentage of annual acorn production by oak nut weevil was 27% in Q. mongolica and 33% in Q. acutissima. This results indicate that the branch-cutting behavior of oak nut weevil may be the most important factor regulating oak population and affecting other predators dependent on acorns.

• 한국환경복원기술학회지
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• 제11권2호
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• pp.123-132
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• 2008

The problems caused by new biological organisms in Ogasawara Island of Japan include : (1) loss of native species' habitats and extinction of native species due to the multiplication of invasive species; (2) reduction of native species and confusion in the food chain in result of invasive species' predation; (3) confusion in genes due to hybridization of new and native plants; and (4) destruction of ecosystem and erosion of earth due to rapid increase of invasive species. The natural ecosystem of preserved areas in Korea is constantly confused and destroyed by new animals and plants, but Korea does not has any solutions because new animals and plants rarely affect human lives. Invasive species are manually introduced by humans and are considered disasters caused by humans. Korea is in desperate need of campaigns as the general public does not understand the seriousness of the destruction and confusion of natural ecosystem caused by new biological organisms and their indirect/direct influences on humans. It is necessary to evaluate the biological characteristics, ecological influence, and harms of invasive species in preserved areas to establish a system to manage invasive species and plan the priority removal of species that are highly harmful and locally distributed. Manual removal and suppression of new biological organisms that cause problems is effective, but it takes cost, effort, and time. Therefore, we would need to research and develop the most efficient and effective techniques and measures to manage invasive species in our ecosystem.

• 한국수산과학회지
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• 제19권5호
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• pp.411-422
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• 1986

부산해운대 동백섬 연안천해에 분포하는 노래미 개체군의 식성을 파악하기 위해 노래미의 위내용물을 분석하고 환경생물을 조사했다. 노래미의 주된 먹이 생물은 amphipoda 및 isopoda에 속하는 갑각류였다. 특히, Gammaridae는 모든 계절에서 어느 연령군의 노래미의 위내용물로부터 우점적으로 출현했다. Caprella sp.는 산란직전의 $8{\sim}9$월에 많이 나타났다. Synidotea laevidorsalis는 위내용물에서 개체수로서는 조성비가 낮았지만, 용적으로서는 Gammaridae 다음으로 조성비가 높았다. 저연령어는 크기가 작은 Gammaridae, Caprella sp., Dynamene sp.를 많이 먹었으며, 고연령어는 크기가 큰 S. laevidorsalis, Polychaeta, Reptantia를 많이 먹었다. 노래미 암수 간의 먹이 생물 차는 없었다. 연중 적극적(positive)으로 선택섭식된 먹이 생물은 Caprella sp.였다. Gammaridae는 봄과 가을(10,11월)에는 적극적으로 섭식되었으나, 여름과 9월에는 소극적(negative)으로 섭식되었다. 먹이 생물의 섭식량은 고연령군일수록 많았다. 노래미가 성장할수록 섭식하는 먹이 생물의 종류는 다양했다. 소형의 먹이 생물은 노래미의 어느 연령군의 위내용물에서도 고루 출현하였다. 한편 대형의 먹이 생물의 경우에는 노래미의 나이가 많을수록 위내용물에서 출현하는 크기가 증가했다.

• Journal of Forest and Environmental Science
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• 제33권3호
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• pp.226-232
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• 2017

Dhup (Canarium resiniferum) is an economically and aesthetically important rare native tree species of Bangladesh. In natural condition 78.5-98.7% seeds do not germinate due to inhibition by hard seed coat, seed predation and unfavorable environmental conditions. A study was conducted in the Seed Research Laboratory and nursery of Institute of Forestry and Environmental Sciences, Chittagong University, Bangladesh in 2013 to find out appropriate pre-sowing treatments for maximizing germination and initial seedling growth. Eleven pre-sowing treatments were provided in both the seeds sown in polybags and seeds sown in propagator house. Results revealed that, germination started at first (after 20 days of seed sown) in seeds immersed in water at room temperature for 24 hours and germination completed within 38 days. Significantly higher (p<0.05) germination percentage (33%), germination energy (16.7%), plant percent (33%) and germination value (0.4) was found with seeds immersed in water at room temperature for 24 hours. Seedling height measured at three, four and five months after the seed germination in case of seeds treated by immersion in water for 24 hours was also greater than others. Therefore, pre-sowing treatment by immersion in water at room temperature for 24 hours was more effective in germination and production of quality vigor seedlings of Dhup.

• Journal of Ecology and Environment
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• 제30권1호
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• pp.49-56
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• 2007

We placed and monitored 2,137 nest boxes to determine how the size of the entrance hole and the box placement influenced nest box selection by secondary cavity-nesting birds and to derive recommendations for the use of nest boxes for management of cavity-nesting birds in forested environments. A total of 566 pairs of seven bird species used the nest boxes from 1997 to 2006, 562 of which were secondary cavity-nesters. Sympatric tits such as varied tits (Parus varius), great tits (P. major), and marsh tits (P. palustris) were common breeding birds in nest boxes, and showed clear preferences for 4.0 cm, 3.5 cm and 3.0 cm nest holes, respectively. Tree sparrows (Passer montanus) and Eurasian nuthatches (Sitta europaea) preferred 4 cm and 3.5 cm holes, respectively. We did not detect selection for the directional orientation for the entrance hole, but the birds appeared to avoid nest boxes that faced steep or gentle upward slopes and those less than 1.8 m from the ground. These results are probably related to avoidance of disturbance and predation. We suggest that diverse species can be supported by the placement of nest boxes with entrance holes of various sizes and that specific species can be targeted by selecting the hole sizes preferred by those species. To attract secondary cavity-nesters, managers should avoid placing nest boxes close to the ground and facing hills. This study also suggests that careful selection and placement of nest boxes is needed to avoid biases in research using nest boxes.

• Journal of Ecology and Environment
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• 제32권4호
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• pp.257-265
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• 2009

We estimated monthly and annual secondary productivity of pelagic zooplankton in Lake Paldang and Lake Cheongpyong. Secondary productivity was calculated by combining estimated zooplankton biomass and biomass-specific productivity for each site and depth from March to November 2008. In addition to somatic production, we measured production of eggs and exuviae for three dominant species: Daphnia galeata, Bosmina longirostris, Cyclops sp. In terms of biomass, B. longirostris was dominant in Lake Paldang in April and May, B. longirostris showed explosive biomass growth, especially in May. In June and July, B. longirostris and D. galeata were both dominant. Lake Cheongpyeong showed much lower zooplankton biomass than Lake Paldang. In August, there was little or no biomass in both lakes probably due to heavy rain. The Gyeongan River contributed most of the secondary productivity and B. longirostris contributed the most secondary productivity in Lake Paldang. D. galeata also contributed in the Gyeongan River, the South Han River and at the Paldang Dam in spring and fall. Overall, Lake Cheongpyeong showed lower secondary productivity than Lake Paldang. B. longirostris made the largest contribution to secondary productivity in the Cheongpyeong Dam area while D. galeata contributed the most near Nami Island. Somatic production constituted ~80% of the total secondary productivity (the sum of somatic, egg and exuvia production) for D. galeata and B. longirostris. Although production-to-biomass (P/B) ratios were usually <<1 B. longirostris sometimes showed very high P/B ratios, probably due to fish predation. D. galeata showed much lower P/B ratios than B. longirostris after the summer at most sites.