• Korean journal of applied entomology
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• v.47 no.2
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• pp.111-115
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• 2008

This study was conducted to distinguish adult morphology of the giant water bug (Lethocerus deyrollei) between over-wintered (OLD) and new-born (NEW) populations using materials collected from Gyodong island in Gyeonggi-do, Korea, as well as individuals reared in the laboratory (LAB population) as a control. As a result, no fundamental differences were found in external body structure between OLD, NEW, and LAB populations. However, marginal area of basal procoxa in ventral prothorax and jointed part of forefemur and foretibia were greatly worn in the OLD population. Mid-claws were shorter than 0.5 times the length of the 2nd mid-tarsus; the membranous margin of hemelytra was greatly worn; and hairs of the 5th abdominal tergum were greatly reduced in the OLD population.

• Korean Journal of Ecology and Environment
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• v.48 no.3
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• pp.176-187
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• 2015

In this study, we hypothesized that the size of wintering crane population would change due to the climate factors. We assumed that wintering population size would differ by climate values in January, which is the coldest period in year. Especially, White-naped cranes were able to choose wintering site between Cheorwon and other alternative place where snow coverage had low influence, differing from Red crowned cranes. For this reason, we predicted the population size of White-naped cranes would fluctuate according to the extent of snow coverage in Cheorwon. Therefore we used snow coverage data based on MODIS and climate data from KMA (Korea Meteorological Administration) that are generally used. We analyzed the crane's population size in Cheorwon in January from 2002 to 2014. The temperature in the Cheorwon increased from 2002 to wintering period in 2007~ 2008 and went down, showing the lowest temperature in 2011~ 2012. With this phenomenon, warmth index showed the similar pattern with temperature. Amount of newly accumulated snow (the amount of snow that fallen from 0:01 am to 11:29 pm in a day) was low after 2002, but rapidly increased in 2010~ 2011 and 2011~ 2012. The area of snow coverage rapidly declined from 2002 to 2005~ 2006 but suddenly expanded in wintering period in 2009~ 2010 and 2010~ 2011. Wintering population size of the White-naped cranes decreased as snow coverage area increased in January and the highest correlation was found between them, compared to the other climatic factors. However, the number of individuals of Red crowned cranes had little relationship with general climate factors including snow cover range. Therefore it seems that population size of the Red crowned crane varied by factors related with habitat selection such as secure roosting site and area of foraging place, not by climatic factors. In multiple regression analysis, wintering population of White-naped cranes showed significant relationship with logarithmic value of snow cover range and its period. Therefore, it suggests that the population size of the White-naped crane was affected by snow cover range n wintering period and this was because it was hard for them to find out rice grains which are their main food items, buried in snow cover. The population size variation in White-naped cranes was caused by some individuals which left Cheorwon for Izumi where snow cover had little influence on them. The wintering population in Izumi and Cheorwon had negative correlation, implying they were mutually related.

• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.4
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• pp.218-225
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• 1992

This experiment was carried out to compare the varietal differences of winter hardiness based on the values of winter hardiness index(W1) and the dry weight of plant per relative tiller appearance rate (DWIRTAR), and the evaluate the method of measurements for winter hardiness in 17 orchardgrass varieties grown under mountainous area of Tackwalyon, Kangwon-do. Korea. The results were summarized as follows: 1. Seedling vigours(SV) of plant before wintering indicated highly significant negative correlation with the dry weight of 1st cutting(DW) and the dry weight of plant per relative tiller appearance rates (DWIRTAR). 2. The dry weight of 1st cutting(DW) indicated significant positive correlations with the number of tillers per plant(NT). dry weight of a tiller(WT), lield survival rate(SR). heading rate(HR) and the dry weight of heading tillers(HDW). 3. Correlation coefficients of the dry weight of 1st cutting(DW) with winter hardiness index(W1) was 0.499(p<0.05), and the dry weight of plant per relative tiller appearance rates(DW/RTAR) was 0.895(p<0.001), respectively. 4. Between the winter hardiness index(W1) and field survival rate(SR) showed highly significant positive correlation(p<0.001). And, the dry weight of plant per relative tiller appearance rates(DW/RTAR) showed highly significant positive correlation(p<0.001) with the dry weight of a tiller(WT) and the dry weight of heading tillers(HDW). 5. The varieties were classified into 2 groups by winter hardiness index(W1). The 13 varieties of Hallmark. lna, Rancho, Amba, Filippa, Sparta, Hokuto, Kitamidori, Okamidori, Wasemidori, Shinyo, Potomac and Summer-green belong to the group of W1)100, and 4 varieties of Able, Juno, Napier and Jesper belong to the group of WI(100, respectively. 6. And, also classified into 2 groups by the dry weight of plant per relative tiller appearance rates (DWIRTAR). The 4 varieties of Amba, Okamidori, Wasemidori and Summer-green belong to the group of DW1RTAR)l.O and 13 varieties of Able, Hallmark, Ina, Juno, Napier, Rancho, Filippa. Jesper, Sparta, Hokuto, Kitamidori, Shinyo and Potomac belong to the group of DW/RTAR(1.0, respectively. The variety with DW/RTAR)I.O is belong to the group of high potential winter hardiness, and also obtained a high values over the 100 of winter hardiness index(W1). 7. The dry weight of plant per relative tiller appearance rates(DW/RTAR) may be a very useful ecological character to evaluate the potential winter hardiness of orchardgrass varieties grown under mountainous area of Taekwalyon(altitudinal ranges about 800m).

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.2
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• pp.93-98
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• 1994

This experiment was canied out to investigated the effect of slope exposure on winter hardiness of grasses in mountainous pastures of Taekwalyong area The results obtained were summarized as follows; 1. Plant vigour(PV) before wintering influenced on the growth of next spring, field survival rates and winter hardiness of grasses. 2. The dry weight of plant per relative tiller appearance rates(DW/RTAR) was significantly negative correlated with plant vigour(PV) before wintering, but the weight of plant per relative tiller appearance rates(DW1 RTAR) were significantly positive correlated with the number of tiller per plant before wintering($NT_O$), number of tillers per plant of 1st cutting(NT), dry weight of plant(DW), field survival rates(SR) and relative tiller appearance rate(RTAR). 3. There ranking order of high winter hardiness of grasses, it were west(W), north-north west(NNW), eastsoutheast( ESE) and south-southwest(SSW) exposure, respectively.

• Korean journal of applied entomology
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• v.37 no.2
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• pp.127-135
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• 1998

To study overwintering biology of the oriental tobacco budworm (OTB), Helicoverpaa.ssulta, OTB larvae were collected from middle and southern region of Korea in the autumn and rearedto diapausing pupae. Diapausing pupae were held at two different locations (Suwon and Chinju) and wererecollected in the spring to observe adult emergence rate and duration to adult emergence at 25$^{\circ}$C. Thesurvivorship of overwintering pupae was less than 5% when the pupae were buried in the soil in 20cmdepth. However, more than 60% of the pupae survived when they were kept in the plastic cup withartificial diet and were buried in the soil. The mean developmental periods of overwintering pupae at 25"C varied from 20.4 days to 43.9 days depending on years and locations where larvae were collected andpupae were held. The proportion of individuals which required longer than 30 days for development washigher in the population from the middle regions than those of southern regions. However, the proportiondecreased when the pupae collected from middle regions were held at Chinju, southern region. Chinju, southern region.

• Korean Journal of Heritage: History & Science
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• v.42 no.1
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• pp.62-70
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• 2009

The study was conducted from Jan. 11 to Jan. 12 2008 on 17 areas which were the wintering area of Aegypius monachus and where the birds were observed. In the study, a total of 1,912 individuals were observed to winter in the areas, which was larger than any previous observation. The study found that 1,500 individuals wintered in the central region of Korea including Gyeonggido and Kangwondo, which accounted for 78.45%, and 412 individuals (21.55%) in the southern region such as Gyeongbuk, Gyeongnam, Jeannam and Jejudo (Island). Given the number of individuals wintering by region, Jangdan Peninsula (777 individuals), Cheorwon (488 individuals) and Sancheonggun(193 individuals) were mostly found. In comparison with the previous studies, 20-30% of the individuals have moved south since 2006. This movement might be attributed to the suspension of feeding campaigns, but the birds still crowded some specific areas.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.321-327
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• 1995

This study was conducted to determine the winter ecology of the small brown planthopper (SBPH), laodelphax striatellus Fallen, in Milyang, east Kyungsangnamdo province. The age distribution in the overwintering SBPH population varied according to collection dates. In early December, the population distribution was 60% 4th instar, 30% 3rd instar, 6% 5th instar, 3.4% 2nd instar with very few adults and 1st instar. In early March 5th instars had the highest propotion (47-50%) with 4th instar 44-46%. In early April the adult population was 75-81% of the population. The averaged nymphal instar converted the age distribution of he overwintering SBPH in to the into the numerical values tended to increase continuously. However, there were some differences in the averaged nymphal instar of overwintering SBPH annually and these differences resulted from different age distribution of the overwintering SBPH due to different annual temperature fluctuations during overwitering periods. The weight of the overwintering SBPH increased continuously during overwintering periods. The collection density of the overwintering SBPH population was significantly higher on the levee than in the barley field. Percent nymphal parasitism by haplogonatopus atratus in the overwintering SBPH population averaged about 21% regardless of overwintering years.

• Korean Journal of Environment and Ecology
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• v.34 no.3
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• pp.191-197
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• 2020

The purpose of this was to examine the differences of large whopper swan (Cygnus cygnus) in wintering habitat preference among bridge sections of the lower Nakdong River of the Nakdong River Estuary, the largest whopper swan's wintering habitat in Korea. This species is designated and protected as Natural Monument in Korea. The survey was conducted in six time-series during the 2018~2019 wintering season, and it found up to 500 whopper swans were wintering in the lower Nakdong River. For the survey, a seven sections were set up based on the bridges across the river. Whopper swans were rarely observed in five narrow sections where the distance between bridges was less than 2 km. The stable population of the whopper swan was observed only in two broader sections where the distance between bridges was is over 4 km. As these sections were relatively little affected by artificial interference, the distance from the mouth of the Nakdong River was not a factor. Securing a stable space is considered as one of the most important factors for wintering of whopper swans, which are an endangered species. The survey results indicate that the distance between bridges should be at least 4 km to secure the whopper swan's stable habitat. These results are expected to be a reference to the development or restoration of the river ecosystems, especially bridge construction.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.4
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• pp.251-256
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• 1993

This experiments was carried out to evaluate the potential winter hardiness of tall fescue varieties based on the data of dry weight of plant per relative tiller appearance rates(DW/RTAR) in mountainous pastures of Taekwalyon area. The results obtained were as follows; 1. The varieties were classified into 2 groups by dry weight of plant per relative tiller appearance rates (DW/RTAR). Thus. Forager and Fuego belong to the group with more than 2.0 in DW/RTAR but Barcel, Barvetia, Demeter, Enforcer. Johnstone, Safe and Stef belong to the group with less than 2.0 in DW/RTAR respectively. 2. The dry weight of plant per relative tiller appearance rates(DM/RTAR) and dry weight of plant(DW) of 1st cutting were significantly positive correlated with number of heading tillers and dry weight of heading tillers. 3. The dry weight of plant per relative tiller appearance rates(DW/RTAR) was significantly positive correlated with dry weight of plant(DW) of final cutting and of 1st cutting. 4. The varieties with high DW/RTAR showed a high dry weight of plant(DW) of 1st cutting. Accordingly, it was concluded that DW/RTAR is a valuable character for evaluating potential winter hardiness of tall fescue on mountainous pastures of Taekwalyon area.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.409-422
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• 2017

In order to understand the environmental factors affecting the waterbird community in winter, we divided the watershed into 6 sections and investigated the size of the stream, the water quality, benthic invertebrates, and fish including birds. The influences on the community of water birds in Wonju stream were river structure, temperature and water quality. Among the structure of the river, the factors affecting the waterbird community in winter were the width of the stream and the width of the flowing water. The wider the width, the more species and the number of the winter waterbirds were. As the width of river water was wide, the smaller the width and width of the waterway, the fewer the population. The temperature changes of the wintering season affected the community of water birds because it led to freezing of rivers. The sections that were not frozen showed a significant increase and decrease in the temperature drop and rise. The values of pH, water temperature, COD, BOD, TN, TP and total E. coli increased with the increase of the downstream waterbirds population in the water quality survey. The water quality of S6 was affected by the downstream sewage treatment plant The number of wintering waterbirds was also highest. The effluent from the sewage treatment plant seems to have a considerable influence on the water quality. The increase of several items such as TN promotes the nutrition of the river, which leads to the accumulation of organic matter and the proliferation of aquatic organisms. This may be the cause of the increase in winter waterbirds as a food source. The benthic macroinvertebrate communities and fish communities did not show any correlation with the wintering water-birds communities.