• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.211.2-211
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• 2003

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• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.169-177
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• 2024

This study investigated whether population dynamic analysis based on the height characteristics of Abies nephrolepis was feasible. It was necessary because existing population dynamic analyses based on age and diameter at breast height (DBH) made it difficult to reflect the slow growth characteristics of Abies nephrolepis in harsh environments of high altitudes. The limitations of population dynamics analysis based on the age and DBH distribution of Abies nephrolepis in Seoraksan, Odaesan, and Taebaeksan National Parks, where Abies nephrolepis populations are representative, were verified, and the characteristics of height growth were investigated to comprehensively analyze whether a vertical structure based on height could reveal the population dynamics. The result of this study showed some limitations in understanding the population dynamics of Abies nephrolepis based on age distribution due to practical difficulties in sampling all trees and variations in age distribution within the same community depending on factors such as light conditions. Moreover, it was challenging to differentiate the distribution of DBH classes at fine levels, making it difficult to reflect the rapid growth characteristics of Abies nephrolepis when light conditions become suitable after prolonged stays in smaller DBH classes under shade conditions. However, a comprehensive analysis of the height characteristics of Abies nephrolepis revealed that the density corresponding to the population dynamic characteristics of Abies was high and adequately reflected the predominant tree death at similar height stages, as well as the U-shaped population dynamics at the lower stratum. Moreover, it was possible to identify a transition point in height values under shaded conditions, where the annual growth of Abies nephrolepis individuals in the lower stratum increases significantly, indicating that Abies nephrolepis individuals can escape from competition with other shrubs and undergo vigorous growth only at this height level. Therefore, this study confirmed that a vertical structure based on height can be utilized to understand the population dynamics of Abies nephrolepis in high altitudes, and it is expected that future studies on height characteristics can intuitively reveal the maintenance status of Abies nephrolepis populations in the field.

• Korea journal of population studies
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• v.26 no.2
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• pp.175-195
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• 2003

This paper investigates spatial distribution of the knowledge-information occupations by utilizing Geographical Information System(GIS). The knowledge-information occupations, comprised mainly of professionals, engineers and managers, have played a key role in the knowledge-based information society. The uneven development of bureaucratization and informatization among regions have resulted in unequal spatial distribution of the knowledge-information occupations. Analysis of 1995 and 2000 Census shows that these occupations tend to concentrate in some major metropolitan areas, while the other areas show rather traditional occupational structure. This spatial unequality has been also found in the occupational distribution within Seoul. This tendency of spatial concentration in the occupational distribution inherited from the industrial society and is not going to diminish in the knowledge-information society. More aggressive policies to make the most of decentralizing impacts of information and communication technologies should be implemented to counter-balance this tendency.

• Journal of Korean Society of Forest Science
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• v.95 no.4
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• pp.435-442
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• 2006

A total of 167 peculiar haplotypes confirmed from 28 cpSR variants that were observed in 19 populations of Japanese red pine in Korea through cpSSR marker analysis. Thirteen individuals that showed identical haplotype dispersed evenly in 10 populations, and the average number of effective haplotype within population was 13.37. Estimate of genetic diversity (He) was 0.987 on the basis of cpSSR haplotype variants that was equivalent to or higher than the estimates reported in other studies on some forest tree species. Estimation of genetic diversity (S.I.) on the basis of cpSSR variants composing each haplotype revealed the highest estimate of 1.109 for the population of Gangwon-Yeongwol and the lowest estimate of 0.411 for the population of Gyeongbuk Mungyeong with the average of 0.887. Most of observed cpSSR variants appeared to exist commonly in 19 populations (97.62%), and genetic differentiation of cpSSR variants among populations was turned out to be weak (${\Phi}_{ST}=0.024$). Relatively fast rate of mutation of cpSSR marker might be a major cause for such weak population differentiation. There was no identical haplotype shared between 39 population pairs of 173 pair-wise population pairs. Estimation of genetic distance among 19 populations on the basis of population pairs was also impossible, that might be resulted from restricted migration among 19 populations. Considering the observed distribution patterns of cpSSR variants in addition to the previous studies on I-SSR variants, informations on the present geographic location and genetic status of populations should be considered together for effective sustainable management of the genetic resources of Japanese red pine in Korea.

• Journal of Wetlands Research
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• v.19 no.2
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• pp.223-229
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• 2017

This study analyzed the relationship between environmental factors and the temporal changes of the bird populations during the every January from 1999 to 2016 (18 years) in Donglim reservoir. 'Winter Waterbird Census of Korea' data by National Institute of Biological Resources were used for the bird population data, and principal component analysis and cluster analysis were used to analyze the changes of annual population. The average temperature of January and the average storage rate of the reservoir were used as environmental factors. According to the results of the study, the population changes in the study area can be explained by the increase and decrease of two water bird groups and a mountain bird group. The average temperature of the years when the population of water bird groups increased was more than $1.4^{\circ}C$ in comparison with the year when mountain birds increased. On the other hand, the influence of the water content was not clear. The visiting of Baikal Teal affected by temperature was a factor affecting the other group of water bird and a mountain bird group. The results of this study suggest that the temperature change affects the global spatial distribution of birds and the migration of large population species such as Baikal Teal affects species composition and populations of birds at local scale. Therefore, understanding of environmental changes at large scale and spatial distribution of species and flock contributes to understand the temporal variation of the bird population at regional or local scales.

• Journal of Environmental Health Sciences
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• v.47 no.6
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• pp.521-529
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• 2021

Background: The coronavirus disease (COVID-19) has caused changes in human activity, and these changes may possibly increase or decrease exposure to fine dust (PM_2.5). Therefore, it is necessary to evaluate the exposure to PM_2.5 in relation to the outbreak of COVID-19. Objectives: The purpose of this study was to compare and evaluate the exposure to PM_2.5 concentrations by the variation of dynamic populations before and after the outbreak of COVID-19. Methods: This study evaluated exposure to PM_2.5 concentrations by changes in the dynamic population distribution in Guro-gu, Seoul, before and after the outbreak of COVID-19 between Jan and Feb, 2020. Gurogu was divided into 2,204 scale standard grids of 100 m×100 m. Hourly PM_2.5 concentrations were modeled by the inverse distance weight method using 24 sensor-based air monitoring instruments. Hourly dynamic population distribution was evaluated according to gender and age using mobile phone network data and time-activity patterns. Results: Compared to before, the population exposure to PM_2.5 decreased after the outbreak of COVID-19. The concentration of PM_2.5 after the outbreak of COVID-19 decreased by about 41% on average. The variation of dynamic population before and after the outbreak of COVID-19 decreased by about 18% on average. Conclusions: Comparing before and after the outbreak of COVID-19, the population exposures to PM_2.5 decreased by about 40%. This can be explained to suggest that changes in people's activity patterns due to the outbreak of COVID-19 resulted in a decrease in exposure to PM_2.5.

• Development and Reproduction
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• v.13 no.2
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• pp.97-103
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• 2009

Genomic DNA samples isolated from four geographical freshwater crab (Eriocheir sinensis) populations collected in the inland of the Korean Peninsula (Gunsan, Paju, and Nampo) and a Chinese site, were used for PCR amplification. Seven decamer primers generated 19 specific loci (19/243 loci, 7.81%) in the Gunsan population, 32 (32/215 loci, 14.88%) in the Paju population, 19 (19/231 loci, 8.23%) in the Nampo population and 62 (62/340 loci, 18.24%) in a Chinese population. The average 8.9 specific loci exhibited inter-individual-specific characteristics, thus revealing DNA polymorphisms in the Chinese population. The number of unique shared loci to each population and number of shared loci by the four populations were generated by molecular analysis using seven primers in four populations. 35 unique shared loci to each population, with an average of 5.0 per primer, were observed in the Gunsan population, and 50 loci, with an average of 7.1 per primer, were observed in the Chinese population. The hierarchical dendrogram indicates three main branches: cluster 1 (GUNSAN 01$\sim$GUNSAN 05, PAJU 06$\sim$PAJU 10 and NAMPO 11$\sim$NAMPO 15) and cluster 2 (CHINESE 16, 17, 18, 19 and 20). Conclusively individual no. 20 of the PAJU 10 freshwater crab was most distantly related to CHINESE no. 20 (genetic distance = 0.667). Taken together, these results demonstrate the potential of RAPD analysis to identify diagnostic markers for the identification of four freshwater crab populations.

• Korean System Dynamics Review
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• v.16 no.2
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• pp.53-74
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• 2015

Nutria(Myocastor coypus) is one of the most notorious invasive species in many countries. The Nutria's original range was South America like Brazil, Chile and Argentina. But it has been introduced to North America, Europe, Africa, and Asia including Korea, by fur ranchers. Like most invasive and disturbing species, nutria not only destroys habitats but also impacts many native species throughout most of its range with destructive feeding behavior. The purpose of this study is to investigate the dynamics of survival mechanism, population increase and spatial distribution, and eradication effect of Nutria on Nakdong River Area with the systems thinking. The result of this study revealed that Nutria can survive during winter with the behavior that the colder the winter was, the more deeply it burrowed. Further, the study uncovered the dynamics that nutria has survived more and more strongly during the extreme cold winter in almost every region and their population has increased dramatically as a result of the uncontrolled reproduction. Finally, the result showed that the action delay in eradicating Nutria, which was originated from the information delay of perception of nutria's survival and reproduction structure, reinforced the spread of Nutria across the nation.

• Ocean Science Journal
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• v.41 no.3
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• pp.139-148
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• 2006

The distribution of the taxonomical composition and the density of meiobenthos depending on the sediment type has been studied in bottom sediments of Nha Trang Bay. The maximal population density and the taxonomical diversity were observed in the silted coarse and heterogeneous sand ($1031.4{\pm}419.7\;ind.\;10\;cm^{-2}$), whereas the minimal level of density and diversity ($588.1{\pm}152.5\;ind.\;10cm^{-2}$) was in the coarse and heterogeneous sand with shell debris and corals. The correlation between the median diameter of sediment particles and population density of meiobenthos has been revealed (r=0.82, p<0.05). In bottom sediments of Nha Trang Bay, twenty six taxonomic groups of meiobenthos were observed. Nematodes dominated in all sediment types. Representatives of four orders, twenty eight families and ninety seven genera of marine nematodes were identified. The vertical distribution of meiobenthos in different sediment types was considered. A sediment column (10 cm height) was sectioned by five 2 cm portions. In the last layer (8-10 cm) the most number of meiobenthic groups was found in sandy sediments. In the lower layers of silt sediments, only nematodes were found.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1706-1712
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• 2014

The OH($X^2{\Pi}$, ${\upsilon}^{\prime\prime}=0,1$) internal state distribution following the reaction of electronically excited oxygen atom ($O(^1D_2)$) with cyclo-$C_3H_6$ has been measured using laser-induced fluorescence, and compared with that following the reaction of $O(^1D_2)$ with $C_3H_8$. The overall characteristics of the OH internal energy distributions for both reactions were qualitatively similar. The population propensity of the ${\Pi}(A^{\prime})$ ${\Lambda}$-doublet sub-level suggested that both reactions proceeded via an insertion/elimination mechanism. Bimodal rotational population distributions supported the existence of two parallel mechanisms for OH production, i.e., statistical insertion and nonstatistical insertion. However, detailed analysis revealed that, despite the higher exoergicity of the reaction, the rotational distribution of the OH following the reaction of $O(^1D_2)$ with $C_3H_8$ was significantly cooler than that with cyclo-$C_3H_6$, especially in the vibrational ground state. This observation was interpreted as the effect of the flexibility of the insertion complex and faster intramolecular vibrational relaxation (IVR).