• Journal of Ecology and Environment
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• v.44 no.4
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• pp.207-211
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• 2020

Adult land crabs generally live on land while their larvae live in the sea. In the case of Sesarma haematoche, female crabs migrate from land to sea to release the larvae at the high tide of syzygy night. Artificial structures along coastal areas are being obstacles for the migration of land crabs and causing synchronized roadkills on coastal roads during breeding migration. In this research, we compared the sex ratios of crab populations in coastal areas with coastal roads and uninhabited island areas with no road. The proportion of females in inland habitats with coastal roads was significantly smaller than island habitats. In particular, females are exposed to the risk of annually repeated roadkills, and the proportion of females decreases rapidly with their growth. If this tendency is general for land crab populations in the coastal areas with roads, significant road mortality of female land crabs during breeding migration can lead to severe population decline in coastal areas. Therefore, it is necessary to take an action to save land crabs crossing coastal roads.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.194-201
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• 2014

To elucidate which climate factors and what periods affect the time of breeding migration of Gori salamanders (Hynobius yangi), we have investigated relationships between the 5-years breeding monitoring data from 2006 to 2010 which had obtained in both natural and translocated breeding sites at Bongdae mountain, Gijang-gun, Busan-si and the matched climate data obtained from the weather station, approximately 25 km apart from the sites. Mean average and mean lowest temperatures during one month before the first breeding migration were related with the time of first female migration in the translocated site. Mean temperature variation and mean precipitation during 60~120 days before the first breeding migration affected the time of 30% male appearance at the natural site and the time of 30% female appearance at both natural and translocated sites. Climate factors were more closely related with female appearance than male and at the translocated site than at the natural site. Our results show that changes in mean temperature variation and mean precipitation rather than mean average temperature might more significantly affect the breeding migration of salamanders, female breeding migration is more closely related with climate factors, and the salamanders translocated could be more affected by climate changes than those in natural populations.

• Journal of Ecology and Environment
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• v.30 no.2
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• pp.121-126
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• 2007

We monitored gold-spotted pond frog (Rana chosenica) populations near the Korea National University of Education in Chungbuk, Korea, from 19 May to 8 August, 2006 to examine the spatial distribution of populations in local areas and to investigate patterns of migration of adult gold-spotted pond frogs from terrestrial hibernation sites to breeding sites, We captured individuals from the largest population using a drift fence with 22 pitfall traps surrounding the breeding site. A total of 22 individuals (19 males and 3 females) were captured between 23 May and 15 June. No peak in breeding migration was detected, but the onset of the breeding migration may correspond with increased humidity. Male body weights were negatively correlated with sampling dates. Seven of 22 individuals were captured at the 4th pitfall trap, which was placed between two culverts. The capture rate per pitfall trap was higher in traps close to the rice field banks (1.44, traps $1{\sim}9$) than in traps facing hilly land (0.33, traps $13{\sim}18$). Comparative data from the Korean frog (Rana coreana), a sympatric species in the study area, were also collected and compared with those of the gold-spotted pond frog.

• International Journal of Stem Cells
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• v.16 no.2
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• pp.202-214
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• 2023

Background and Objectives: To investigate the role of exosomes from periodontal ligament cells (PDLCs) in bone marrow mesenchymal stem cell (BMSC) migration. Methods and Results: Human PDLCs were applied cyclic tension stretching. Exosomes were extracted from cultured PDLCs by ultracentrifugation, then characterized for their size, morphology and protein markers by NTA, TEM and western blotting. The process that PKH26-labeled exosomes taken up by BMSCs was assessed by confocal microscope. BMSC migration was examined by Transwell assay. Exosomes derived from PDLCs were identified. Cyclic tension stretch application on PDLCs can enhance the migration ability of BMSCs through exosomes. The exosomal miRNA expression profiles of unstretched and stretched PDLCs were tested by miRNA microarray. Four miRNAs (miR-4633-5p, miR-30c-5p, miR-371a-3p and let-7b-3p) were upregulated and six (miR-4689, miR-8485, miR-4655-3p, miR-4672, miR-3180-5p and miR-4476) were downregulated in the exosomes after stretching. Sixteen hub proteins were found in the miRNA-mRNA network. Gene Ontology and KEGG pathway analyses demonstrated that the target genes of differentially expressed exosomal miRNAs closely related to the PI3K pathway and vesicle transmission. Conclusions: The exosomes derived from cyclic tension-stretched PDLCs can promote the migration of BMSCs. Alternation of microRNA profiles provides a basis for further research on the regulatory function of the exosomal miRNAs of PDLCs during orthodontic tooth movement.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.489-494
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• 1998

This paper describes a design of graphical user interface for a simulated breeding tool with multifield. The term field is used here as a population of visualized individuals that are candidates of selection. Multi-field interface enables the user to breed his/her favorite phenotypes by selection independently in each field, and he/she can copy arbitrary individual into another field. As known on genetic algorithms, a small population likely leads to premature convergence trapped by a local optimum, and migration among plural populations is useful to escape from local optimum. The multi-field user interface provides easy implementation of migration and wider diversity. We show the usefulness of multi-field user interface through an example of a breeding system of 2D CG images.

• Journal of Ecology and Environment
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• v.30 no.4
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• pp.287-292
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• 2007

We monitored a breeding population of the Asian toad (Bufo gargarizans), in the Wonheunge pond at Sannamdong, Chungju, from 5 March to 11 April, 2006 and 14 February to 31 March, 2007 to investigate their movement patterns, breeding population sizes, and physical characteristics. Terrestrial migration to the pond started on 5 March in 2006 and 14 February in 2007. We captured a total of 266 immigrating individuals (213 males, 53 females) in 2006 and 307 (222 males, 85 females) in 2007, and found 50 adults apparently killed by motor vehicles while migrating to the pond in 2007. Emigration from the pond to terrestrial sites started on 15 March 2006 and 5 March 2007. We captured a total of 245 emigrating toads (181 males, 65 females) in 2006 and 99 (92 males, 7 females) in 2007. An additional 10 emigrating adults were found dead on the road. During both the immigration and emigration periods, two peaks in capture frequency appeared for each sex in each breeding season. The immigration peaks corresponded with higher temperatures, while the emigration peaks corresponded with high humidity. Migrating Asian toads showed sexual size dimorphism and a male-biased sex ratio. Body weights and SVL (snout-vent length) of immigrating and emigrating individuals were negatively related with migration dates.

• Korean Journal of Environment and Ecology
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• v.29 no.5
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• pp.681-692
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• 2015

It is well documented that physiological and nutritional condition of wintering birds is strongly related to migration success to breeding sites, and also breeding success. However, how abiotic factors during winter affect the migration and breeding successes still remains unclear. Thus, this study developed a dynamic-state-dependent model for wintering life-history to identify the potential impact on the life-history, success to breeding site and breeding success of wintering birds, which are related to temperature fluctuation, interspecific competition and human disturbance at the wintering sites. To find the best-fit-model, we referred to the existing research data on wintering ecology of Red-crowned cranes (Grus japonensis) in Cheolwon, Korea, which is well documented as a long-term wintering study. Our model predicted that the higher temperature fluctuation and a higher rate of human disturbance are negatively related to migration success to breeding sites and their fitness, ultimately breeding success via changing of proportion in resource allocation (for e. g., lower energy compensation or higher level of stress accumulation). Particularly, the rate of body mass compensation after arrival at wintering sites may be accelerated when there are less temperature fluctuations and a lower rate of human disturbance. In addition, the rate of interspecific competition sharing the wintering foraging sites is negatively related to the rate of body mass compensation. Consequently, we discussed the conservation strategies of wintering birds based on the outcomes of the model.

• Journal of Ecology and Environment
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• v.42 no.4
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• pp.285-291
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• 2018

The impact of climate change on animals has been globally documented. Especially, migration of birds has been extensively monitored as migratory birds are susceptible to any changes occurring both on breeding grounds and on wintering grounds. However, in contrast to spring migration, the patterns and the factors for autumn migration have not been well documented. In this study, we investigated the relationship with climate condition and the first arrival dates (FADs) of bean geese (Anser fabalis) and white-fronted geese (A. albifrons), the representative group of wintering birds in South Korea, using the data collected by Korean Meteorological Association during 1995-2016. Average temperature of September in wintering grounds has increased, and the FADs of the geese have advanced over the 22 years. Even when the influence of autumn temperature was statistically controlled for, the FADs of the geese have significantly advanced. This suggests that warming has hastened the completion of breeding, which speeded up the arrival of the geese at the wintering grounds. In order to assess the effect of climate condition on the arrival of the wintering migratory birds such as the geese in more detail, extensive data collection over many sampling sites and with long-term monitoring is needed.

• Journal of Ecology and Environment
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• v.31 no.3
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• pp.183-191
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• 2008

To determine the age structure of a Hynobius leechii breeding population and analyze relationships between the order of entrance to breeding ponds and physical parameters and age, we studied a wild population of the species in the Research Forests of Kangwon National University in Chuncheon, Kangwon, South Korea from March 16 to April 13, 2005. The age of breeding males ranged one to nine years old and that of females ranged from three to nine years old. The asymptotic sizes of males and females were 6.36 and 6.51 cm, respectively, and the growth coefficients of males and females were 0.71 and 0.81, respectively. The snout-vent length (SVL), head length, and body mass of males were all positively correlated with their age, but female age did not show a significant relationship with any physical parameter. The tail depth, body mass, and condition factors (SVL/body mass $\times$ 100) of both males and females were negatively related with the order of entrance to the breeding pond. The head width and SVL of males were also negatively correlated with the order of entrance, but the SVL of females was positively related with the order of entrance. These results suggest that physical parameters are more important determinants of breeding migration patterns than age. We discuss which of two hypotheses, the mate opportunity hypothesis and the susceptibility hypothesis, is better able to explain the order of entrance to breeding ponds for male and female H. leechii.

• The Korean Journal of Ecology
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• v.24 no.4
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• pp.219-222
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• 2001

The study was conducted to get the basic information for proper protection and management of black-faced spoonbill and their habitats in western coast of South Korea. The species was observed in 8 sites of western coast of South Korea in spring 2000. We confirmed breeding of this species at least 4 pairs in Seokdo island. This island is considered likely to be an imortant breeding site together with Yodo island, Hambakdo island and Yokdo island. Also, we observed breeding of herring gull in Seokdo island and small island nearby Boleumdo island for the first time in South Korea. Chilsando island, Cheonsuman bay and Gyeokyeolbiyeoldo island were considered as stopovers located on the Korean Peninsula route. The other sites were considered as summering sites of the black-faced spoonbill. Especially the birds were constantly observed from breeding season to postbreeding season in Seonduri and Yeochari of Ganghwado island. We have counted maximum 88 individuals gathered at Gaksiyeo in Seonduri and Yeochari on September 3, 2000. The species seemed to gather at these sites after breeding for migration to wintering ground in September. We also surveyed changes of the number of individuals as time of the ebb and flow on September 3 and 6, 2000, their time budgets were affected by the ebb and flow in these sites.