• Korean journal of applied entomology
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• v.53 no.3
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• pp.311-315
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• 2014

Lantern fly(Lycorma delicatula) is a major invasive pest that causes withering symptom of agricultural crops by sucking tree sap and sooty mold symptom by producing honeydew. This study was conducted to investigate the occurrence pattern of lantern fly in grape orchards in Gyeonggi area and the effect of winter temperature on L. delicatula egg survival during 2010 to 2013. In Gyeonggi areas, overwintered L. delicatula eggs began to hatch from early May and nymphs peaked in mid May. Adults emerged from late July and laid eggs until early November. The survival of L. delicatula eggs during overwintering was largely affected by winter temperatures. The relationship between the number of days below a threshold temperature (x) in January and the survival rate of overwintering L. delicatula eggs (y) was using linear regression model. The best model selected by the lowest RSS (residual sum of square) between predicted and actual survival was y = -1.0486 x + 94.496 ($R^2=0.7067$) with $-11^{\circ}C$ of threshold temperature. These results should be helpful to conduct L. delicatula management programs, since the results provided relivable prediction for the winter survival of L. delicatula eggs and the phenology of egg hatch in the spring.

• Journal of Wetlands Research
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• v.26 no.3
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• pp.285-297
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• 2024

This study, conducted in Geolpo-dong and Gamjeong-dong near Gimpo-Hangang New Town, examines an area adjacent to the Han River estuary, a major wintering ground for migratory birds. Over 59 surveys from October 2015 to March 2022 in four representative rice fields (sites A-D) recorded 44,942 individuals from 32 genera and 72 species. Site D, a large area near the Han River, exhibited high species diversity. Despite lower diversity in areas under development (sites A, B, C), ongoing species influx and utilization persist. The study focuses on Anser fabalis, a species predominantly utilizing rice fields, and identified their distribution characteristics. The analysis revealed 162 instances of population influx, with over a 30-fold increase observed across 39 surveys conducted over a 30-month period (October to March, '15~'22). The area, a key wintering site for migratory birds of Janghang Wetland, about 5 km from feeding sites, is heavily utilized by migratory geese, indicating the region's high value considering migration distance and anticipated continuous bird influx despite urban expansion. Therefore, future developments should preserve ecological corridors and connected stepping stone habitats to not only preserve existing habitats but to secure alternative feeding sites, ensuring smooth movements and mitigating habitat loss.

• Korean Journal of Environment and Ecology
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• v.27 no.3
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• pp.305-315
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• 2013

This study is aimed to provide the preliminary data for conservation and management of wintering site for Anser fabalis population in Cheongna Area, Incheon Free Economic Zone, Korea through analyzing the relationship between the biotop structure of its wintering site and behavior characteristics. The main types (size and ratio) of the biotope in Cheongna Area, Incheon Free Economic Zone are reed wetlands ($6,093,762m^2$, 47.8%), rice fields without rice straw ($2,927,916m^2$, 23.0%), and rice fields with rice straw ($1,915,655m^2$, 15.0%). According to the survey carried on 13th Feb., 2013, total 33 species and 6, 535 individual birds were observed and among of them, the dominant bird was Anser fabalis showing 5,128 indiviuals, 78% of total population. As the result of analyzing the migratory route of Anser fabalis, the bird moved from roosting site to foraging site before and after sunrise and from feeding site to roosting site before and after sunset. According to the analysis of interrelation between habitat characteristics and biotope types of the bird, population density was the highest in reed wetlands among habitat types and individual appearance was the highest in water-filled rice field melting ice. The bird ate the roots and bulb of hydrophytes in reed wetlands and showed various behaviors like eating dropped grains, resting and sleeping in water-filled rice fields and eating dropped grains and resting in rice fields with and without rice straw. It is shown that the number of Anser fabalis appearing in rice fields is depended on the presence of dropped grains than types of rice field.

• 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 Environment and Ecology
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• v.30 no.2
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• pp.165-172
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• 2016

Mallard and Spot-billed ducks that are typical wintering water birds use the wide rice field in the center of the water system as a wintering ground. I try to figure out the daily movement distance from Home-Range to wintering ground for mallard and spot-billed ducks in Mangyunggang, Dongjingang where located in central region. In 2015 wintering period by using a Cannon-net, I attached WT-300 to 5 mallard and 5 spot-billed ducks. Daily movement distance is an overall average 0.89km, the largest distance was 31.09km. Daily movement distance of mallard was 0.97km, the largest distance was 28.78km. Daily movement distance of Spot-billed ducks was 0.80km, the largest distance was 33.39km. Home-Range analysis is used by the SHP files that is compatible with GIS and ArcGIS 9.0 Animal Movement Extension, it was analyzed using the Minimum Convex Polygon Method (MCP) and the Kernel Density Estimation (KDE). The behavior rights of two kinds of ducks was $490.34km^2$ by Minimum Convex Polygon Method (MCP) ($SD=311.20km^2N=10$), an important habitats Kernel Density Estimation (KDE 50%) was $42.24km^2$. Home-Range of Mallard (MCP) was $568.02km^2$, it is wider than home-range(MCP) of spot-billed duck $397.13km^2$ relatively, the core habitats of mallard is $53.05km^2$, it is wider than mallard's core habitats(KDE 50%) $29.26km^2$ relatively.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.939-961
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• 2016

For effective conservation of endangered wild plants, it is necessary to understand their interactions with environmental factors in each habitat together with life traits of target species. First, the characteristics of their distribution were investigated followed by their monitoring for 4 years focusing on the habitats in the lagoon. Also, their life traits were compared including production of hibernacles, fruits, and seeds by the soil fertilization and light intensities. Next, the information on the species was secured by germination experiment using the generated seeds from the cultivation experiment. The habitat of Glaux maritima var. obtusifolia Fernald in Korea was located in the rear edge of the worldwide distribution and its four habitats were isolated and distributed far away each other. Two of them were located in small salt-marsh and fine sand estuaries formed in the rocky area of the seashore, and the other two were inhabited with the sandy soil in the lagoon which was connected by river-mouth to the sea. Glaux maritima var. obtusifolia Fernald tends to be distributed in the sites where the establishment and growth of the competitor were inhibited by salinity, periodic flooding, and lower layer of the soil to extend a roots. It maintained its population by recruitments of hibernacles and seedling. The production of hibernacle was assumed to be affected by the particle consist of the sand together with organic matters in the soil. Seedling recruitment was observed only in the salt-marsh area located in the rear sites of sand ridge where was the shore of the lagoon. Glaux maritima var. obtusifolia Fernald was observed to have different threatening factors by each population. Its population in Pohang seemed the sedimentation of fine sand which affected the recruitment of hibernacles had been eroded due to the construction of the coastal road. The population in Ulsan appeared rapid expansion of competitor and reduction of its distribution area due to the interruption of eluted water supplied to the habitat. On the other hand, the habitat in the lagoon maintained the population relatively stable. Especially, the population in Songji-ho was determined to be the most stable one. To sustain the population of Glaux maritima var. obtusifolia Fernald distributed in the lagoon, it is suggested that the wide ranged scale of conservational activities is necessary to maintain the mechanisms including the entrance of seawater which belongs to the lagoon, and periodic flooding.

• Korean Journal of Environment and Ecology
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• v.22 no.6
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• pp.632-639
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• 2008

This paper deals with feeding site distribution aspect and seasonal distribution change of the wintering geese in Cheonsu bay and reclaimed area from October 2006 to March 2007. Geese were distributed mostly in agricultural land(rice field) during day time. According to the distribution map by maximum counts, observed geese of agricultural land were frequently distributed in large agricultural land. Especially, Geese were more used agricultural land near the reservoir where used as roosting site than the other sites. Diurnal feeding site of the geese were agricultural land near the reservoir with huge flock during early wintering season(October), but geese were used the agricultural land far from reservoir after mid wintering season(after January). The feeding flock size of Geese were decreased and feeding site was more far from the reservoir than in mid wintering season during late wintering season(March). Habitat use rate of the quadrat area where below 1km from the reservoir was most high in early wintering season. Contrary, habitat use rate where 2km far from the reservoir was shown lowest habitat use rate in early wintering season, but it was increased during mid wintering season(January) and decreased after mid wintering season. Habitat use rate of the agricultural land where 2km below and 1 km far from reservoir was shown middle rate, but it was increased until November and decreased after November. This result shown that feeding site preference of the wintering geese was affected by distance from roosting site(reservoir), and feeding site was changed as a food sources decreasing by stay time of geese flock.

• Korean Journal of Organic Agriculture
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• v.31 no.4
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• pp.413-426
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• 2023

These experiments were conducted for 3 years from 2021 to 2023 to develop a method that can be safely used to prevent the leakage of Golden apple snails (Pomacea canaliculata) from eco-friendly rice plantations. In the southern part of Jeollanam-do, after planting rice, the young golden apple snails placed in the rice field become adults around mid-July and begin spawning. These individuals can overwinter in drains that do not dry out, but individuals hatched after mid-July will not mature enough to overwinter. The size of golden apple snails overwintered in the drainage canal was more than 2.5cm in shell height. Installing a net at the inlet could block 95% of the inflow of snails, and 99% of outflow was blocked by installing an improved water trap and net at the drain. During the mid-drying period and pre-harvest drying period, a water path was created with a power paddy pottery machine. 59.5% of snails were attracted to the waterway, and it took 130 minutes to build the waterway and collect the snails. Based on these results, seasonal paddy management tips for the safe use of giant snails in rice fields were suggested.

• Korean Journal of Environment and Ecology
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• v.33 no.1
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• pp.1-8
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• 2019

Pintail (Anas acuta) is the major wintering bird in South Korea and known as a major mediator of the highly pathogenic avian influenza (HPAI). Pintail migrates long distances between Russian Siberia and Korea. This species prefers a rice paddy area as their winter habitat. The purpose of this study is to provide the data necessary for the conservation and management of bird habitats in Korea by understanding the wintering home-range and habitat of pintail in Korea. We captured six pintails using a cannon-net in the winter of 2015 and attached the GPS-mobile phone based telemetry (WT-300) on them to study the wintering home-range and wintering habitat. We analyzed the tracking location data using ArcGIS 9.0 Animal Movement Extension and calculated Kernel Density Estimation (KDE) and Minimum Convex Polygon (MCP). The average home-range in the wintering ground analyzed by MCP was $677.3km^2$ (SD=130.2, n=6) while the maximum and minimum were $847.7km^2$ and $467.5km^2$, respectively. Extents of home-range analyzed by KDE were $194.7km^2$ (KDE 90%), $77.4km^2$ (KDE 70%), and $35.3km^2$ (KDE 50%). The pintails mostly used both sea and paddy field as habitat in the winter season and utilized paddy fields more during the nighttime and than the daytime. We concluded that the home-range and habitat of pintails in the winter could be used as the reference data for the preservation of species, management of habitats, and coping with a breakout of HPAI.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.561-567
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• 2011

Cold tolerance of the native Rhododendron species which are on the verge of extinction in Korean nature were compared with the introduced species and its mechanism were studied physiologically with the investigation of the leaf angle, leaf curling, and photosynthetic activity. The degree of cold tolerance measured with the leaf burning after winter season was higher in the native species, Rhododendron brachycarpum and Rhododendron brachycarpum var. roseum than all the introduced species. 'Nova Zembla', an introduced species, showed high sensitivity to the low temperature. Changes in leaf angle by the low temperature were bigger in 2 native species and 'Parker's Pink' than the other introduced species and small comparatively in 'Nova Zembla' and 'Cunningham's White' cultivar. Leaf curling also occurred strongly in 2 native species by the low temperature. While, it was comparatively little and mild in the other introduced species. Therefore these results suggested that the leaf movement such as leaf angle change and curling adapted to the low temperature is positively related to the cold tolerance of 2 native species. By the way, such relationship is not explainable in the cold-sensitive 'Parker's Pink' cultivar showing comparatively stronger leaf movement. Photosynthetic activity measured before the winter season was high in the cold-tolerant R. brachycarpum and its recovery after winter season was faster in the 2 native species and the introduced 'Cynosure' cultivar than the other introduced species. They were the lowest in the most cold-sensitive 'Nova Zembla'. This phenomena occurred similarly even in the stomatal conductivity, suggesting that the movement of water from the roots to the leaves is better and then the leaf burning after winter season become small in the cold-tolerant species. The recovery of photosynthetic activity and stomatal conductivity was comparatively slower in the cold-sensitive 'Parker's Pink'. From the above results, leaf behavior adapted to the low temperature during the winter season and water movement to the leaves are related collectively to the cold tolerance represented as the leaf burning in the Rhododendron species is suggested.