• Korean journal of applied entomology
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• v.57 no.4
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• pp.415-423
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• 2018

Aphid is a typical vector that transfers various kinds of viruses to potatoes. Therefore, it is very important to control aphids moving into potato fields. We investigated the seasonal movement pattern of aphids and its virus transmission rates mainly in the three seed potato production regions at highland in Gangwon-do, Korea. In addition, we identified the aphid species with over-wintering eggs collected from barks or twigs of total 57 tree species around potato fields in winter season. The peak time of summer and winter migration of aphid was at the mid-June and the early October, respectively. A 2.8% of total aphid trapped in yellow water-pan trap was turned out PLRV-borne, and the virus transmission rate was 15.4% by Myzus persicae and 9.1% by Macrosiphum euphorbiae. PLRV-borne aphids started to flow in from the late May, and virus transmission rate of aphid trapped in mid-June was the highest with 10.4%. Totally 14 species of aphid eggs wintered in the 17 species of trees including Acer pictum subsp. mono and Acer pseudosieboldianum at the 11 sites. In particular, because it is not certain that Betula platyphylla var. japonica and Yamatocallis hirayamae do transmit potato virus, but they over-wintered in host plants distributed over a wide area, further research on transmission ability is necessary.

• Korean Journal of Medicinal Crop Science
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• v.3 no.1
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• pp.56-60
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• 1995

Experiment for analysing changes of growth, tuber yield and total sugar content during wintering was performed with Maekmoondong 1(L. platyphylla WANG et TANG). The growth of over ground characteristics including leaf length, tiller number and fresh leaf weight lasted to the middle of April. The growth and filling of tuber were progressed and got to the top of tuber yield (387kg/l0a) in the middle of March, showing the optimum harvesting time in Big Blue Lilyturf cultivation. Total sugar content showed the highest value(79%) in the late of January and was decreased gradually to the middle of March during wintering. There was highly significant negative correlation between total sugar content and tuber yield.

• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.213-220
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• 1994

This study was conducted to investigate bird community and to suggest a proper way how to manage and protect bird community in Tokyusan National Park. The survey was carried over 2 main trail districts by line transect method at 20, February and 22, July in 1993. The observed birds were belong to 5 orders 17 families 34 species, they also have Sparrow Hawk Accipiter nisus, Kestrel Falco tinunnculus(natural monument no. 323), White-backed Woodpecker Dendrocopos leucotos(R) and Japanese Waxwing Bombycilla japonica(R). It is estimated that grass region above 1,000m altitude provided breeding habitats for Gray-headed Bunting Emberiza fucata in summer and wintering habitats for Rosy Finch Leucosticte arctoa in winter, This shows that this region should be protected for inhabitation of these birds. Mujukucheontong valley of Tokyusan National Park, which had been a good habitat for valley-inhabituating birds before twenty years ago, has a lower species richness by increasing using density, and so this valley shoud be properly managed urgently.

• Korean Journal of Environmental Agriculture
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• v.32 no.4
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• pp.294-303
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• 2013

BACKGROUND: It is well known that rice-fields can provide excellent foraging places for birds including seasonal migrants, wintering, and breeding and hence the high biodiversity of rice-fields may be expected. However, how environmental change including climate-changes on life-history and population dynamics in birds on rice-fields has not been fully understood. In order to investigate how climate-change affects population migratory patterns and migration timing, I modeled a population dynamics of birds in rice-fields over a whole year. METHODS AND RESULTS: I applied the Lotka-Volterra equation to model the population dynamics of birds that have been foraging/visiting rice-fields in Korea. The simple model involves the number of interspecific individuals and temperature, and the model parameters are periodic in time as the biological activities related to the migration, wintering and reproduction are seasonal. As results, firstly there was a positive relationship between the variation of seasonal population sizes and temperature change. Secondly, the reduced lengths of season were negatively related to the population size. Overall, the effects of the difference of lengths of season on seasonal population dynamics were higher than the effects of seasonal temperature change. CONCLUSION(S): Climate change can alter population dynamics of birds in rice-fields and hence the variation may affect the fitness, such as reproduction, survival and migration. The unstable balances of population dynamics in birds using paddy rice field as affected by climate change can reduce the population growth and species diversity in rice fields. The results suggest that the agricultural production is partly affected by the unstable balance of population in birds using rice-fields.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.151-165
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• 2015

This study surveys and analyzes the ecology of Gangseo area to be developed near Nakdonggang River and West Nakdonggang River in Busan - before its development. With the result of the surveys as its basis, the study also finds ways to conserve the area's bird habitats in response to the planned development. According to the site surveys over four seasons, West Nakdonggang River which is near the targeted development area is a wintering ground for migratory birds. Some representative bird types in this area are ducks, geese, and other water birds. There are even six legally protected species. The average altitude of their flight is calculated to be $92.4{\pm}18.8m$ and the main purpose for the migration is determined to be for food. According to evalution of the conservation value of the area, Nakdonggang River and West Nakdonggang River turns out to have the highest conservation value. Other areas are developable as long as it was environmentally friendly. Therefore, this study suggests incorporation of ecological parks and biotopes within the targeted development area along with the proposal for spaces in the surroundings where the wintering birds can rest and feed. Especially for the wintering birds that rest at Nakdonggang River and West Nakdonggang River, their flight direction and pattern was examined to determine that their resting ground should be located 50~100m off of the river bank. Furthermore, this study proposes ways to maximize bird habitat by building ecological corridors between the agricultural channel and other small streams in the targeted development area and the habitats in the surroundings. Lastly, the study suggests the construction of low buildings, at most 20m in height, near Nakdonggang River and West Nakdonggang River considering the birds' flight altitude and direction.

• Journal of Ecology and Environment
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• v.31 no.3
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• pp.207-211
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• 2008

We investigated the leaf demography of a temperate woody liana, Akebia trifoliata, in a temperate forest in Japan, Akebia is semi-evergreen: some leaves are shed before winter, while others remain through the winter. Previous studies of semi-evergreen species found that variation in leaf life span was caused by variation in the timing of leaf emergence, Leaves that appeared just before winter over-wintered, while leaves appearing earlier were shed, However, it is unclear whether leaves of the same cohort (i.e., leaves that appear at the same time within a single site) show variation in life span under the effect of strong seasonality. To separate variation in life span among the leaves in each cohort from variation among cohorts, we propose a new method - the single leaf diagram, which shows the emergence and death of each leaf. Using single leaf diagrams, our study revealed that Akebia leaves within a cohort showed substantial variation in life span, with some over-wintering and some not. In addition, leaves on small ramets in the understory showed great variation in life span, while leaves on large ramets, which typically reach higher positions in the forest canopy, have shorter lives, As a result, small ramets were semi-evergreen, whereas large ramets were deciduous, The longer lives of leaves on small ramets can be interpreted as a shade-adaptive strategy in understory plants.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.383-392
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• 2015

We investigated the induction of pupal diapause and number of generation for H. armigera using outdoor rearing and sex pheromone trapping in Suwon, Korea. Over-wintering pupae were induced when neonate larvae were reared in the outdoors from late Aug. to early Oct. in 2013 and 2014. H. armigera adults emerged from late May to early Jun. for 2013 colonies and from late May to late Jun. for 2014 colonies. The colonies placed after mid September produced only diapause pupae, to show environmental conditions that day-lengths on the rearing start date were 11 h 49 min~12 h 24 min, and mean temperatures before pupation were $14.8{\sim}20.7^{\circ}C$. Summer diapause was not observed in all colonies. The peak occurrence of H. armigera adults from sex pheromone trap in Suwon and Hwaseong were pooled and showed four generations (1st: from late Apr. to mid Jun., 2nd: from mid Jun. to late Jul., 3rd: from mid Jul. to late Aug., 4th: from late Aug. to mid Oct.). A degree-day model for development of H. armigera developed by Mironidis and Savopoulou-Soultani (2008) was used to validate the number of generation from field observations using pheromone traps. The 3rd and over-wintering generations were mainly overlapped. It was decided that H. armigera has one over-wintering and three complete generations in a year, and diapause is induced from offsprings of the 3rd and 4th generations adults. It is expected that larvae of the 1st and 2nd generations give a damage to ear zone in maize fields in which have been planted during April.

• Food Science and Preservation
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• v.9 no.1
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• pp.85-91
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• 2002

Quality changes of over-wintering satsuma mandarin (Citrus unshiu Marc. var. miyagawa) during storage by chitosan and calcium treatment and type of storage warehouse were investigated. Citrus were treated with 2000-folds diluted iminoctadime-triacetate solution and 1.5% chitosan with 0.5% CaCl$_2$ solutions and were at 30$\^{C}$ far 24 h before storage. The citrus of about 12 kg/26 L plastic container were stored at room temperature, and at 4$\^{C}$ with 87% relative humidity. Chitosan and CaCl$_2$ solution treated citrus fruits were showed lower in decay ratio than the ones without treatment. Also, these chitosan and calcium treated citrus fruits skewed less in weight loss, that seems it also has restraining effect of fruits' transpiration. Decay ratio of citrus with precise temperature and humidity control were lower than the others during storage. Weight loss, moisture content of peel and flesh were decreased slowly during storage. 0.84 ∼0.90% of acid content were decreased on 120 days' storage. Reducing sugar of citrus was decreased rapidly after 90 days, and vitamin C content were also decreased rapidly after 60 days during storage.

• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.58-66
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• 2009

The telemetry of eight adult manchurian trouts (Brachymystax lenok tsinlingensis) in the upper part of the Nakdong River, which is the southern limit of distribution of manchurian trout on the Korean peninsula, was used to examine migration patterns and evaluate characteristics of over-wintering and the spawning season between December, 2007 and May, 2008. Based on the tracking data, the tagged fish showed a limited migration between adjacent pools, moving only up to $8.6m\;day^{-1}$ during the winter season (December to February). Hydraulic conditions of over-wintering pool areas were, ca. 1m depth, slow moving surface water with areas of sand and gravel. The migration of tagged individuals was successful, moving up to $96.2m\;day^{-1}$ during the spawning season. Two tagged individuals (BL4, BL6) exhibited upstream migration, whereas others showed downstream movements. The timing of upstream migration of the two individuals was consistent with an increasing phases of water level and discharge. The fishes migrating toward the down stream moved to the wide pool areas downstream, where they spent the summer season for the growth.

• Korean Journal of Environmental Biology
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• v.29 no.3
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• pp.113-125
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• 2011

Seabirds have adapted to life in marine environments. More than 25% of the bird species observed in South Korea are seabirds, using the coast area of Korean peninsula as a stop-over and wintering, and breeding site. The aims of this review are to provide information about migratory and resident Korean seabirds and to discuss the methods that are currently employed to monitor the marine environment. In Korea, it has been reported that more than 400,000 individuals of seabirds breed on Nando Islet, Chilbaldo Islet, Guguldo Islet, Sasudo Islet, Hongdo Islet and Dokdo Islet. In 2010, approximately 160,000 seabirds also visited South Korea during the winter. Two of the main treats were introduced wildlife and habitat destruction by humans. Seabirds are monitored mainly at the population and individual levels. The assessment of population sizes and biomagnifications of pollutants are performed preferably at the community and population levels. Behaviour, growth, morphological characteristics, and breeding success is analyzed at the individual level and employed to gauge the health of the marine environment. In addition, we could suggest that molecular technique of seabirds successfully adopted to investigate the effects of pollutants and toxins in the marine environment.