• Korean journal of applied entomology
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• v.46 no.3
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• pp.437-444
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• 2007

The effect of environmental factors on the over-wintering success of the apple snail, Pomacea canaliculata, which is considered as unable to hibernate during winter climate in Korea. This study was examined to determine the location of over-wintering habitats in the agricultural water system related with weed control using the apple snail in rice paddy field in the Yeongnam district from 2003 to 2006. Over-wintering success of the apple snail was observed at Hadong, Hapchen, Sanchung, Kimhae, Milyang, Changwon, Ulsan, Busan, Gyengju, Pohang, Chilgok, Seongju, Gumi, Sangju and Youngju in Yeongnam area. And the over-wintering locations of apple snail going north year by year. Accordingly, the successful over-wintering sites observed were deep wells, water running canals and brooks not dried conditions. A special feature of this sites was that the water of this sites was not frozen during winter season.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.439-444
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• 2016

Maruca vitrata is a main insect pest against crops of Vigna species (V. angularis and V. radiata) and Sesbania sesban in Fabaceae, but the life cycle of the insect is unclear in Korea. In order to know over-wintering possibility, its stage of the insect, over-wintering entry season, and the first adult emergence season of the next year, we investigated over-wintering rates of the insect in outdoor conditions in Suwon ($37^{\circ}16^{\prime}N$ $126^{\circ}59^{\prime}E$ 35ASL). In all colonies which the rearing for larvae, pupae and eggs started after mid-September, adults did not emerge within the year, and all insects died before next June. In several trials for over-wintering of larvae and pupae in soil, all insects died, too. Larvae stored during specified periods at low temperatures (10 and $13^{\circ}C$) did not emerge. From the results, it was postulated that M. vitrata does not have an adaptability to temperature below zero, and cannot over-winter in Suwon area.

• 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.

• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.365-372
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• 2018

The Wintering Waterbird Census of Korea was started in 1999 and monitors 200 major migratory sites in South Korea. Waterfowl counts have been undertaken for more than 20 years since; however, a limited number of studies have analyzed the temporal patterns of waterfowl population. In this study, we analyzed population size changes of wintering whooper swan (Cygnus cygnus) at 112 monitoring sites from 2001 to 2018. The average number of whooper swans was $4,296{\pm}42.66$ and there was a trend for an increase in population size across the survey period. We found that the population in the Nakdong River Estuary, one of the major wintering sites over 18 years (26.22% of the national population), had rapidly decreased (-0.77% per year). Conversely, the whooper swan population in the Junam Reservoir and Sihwa Lake increased (+1.64%, +0.54% per year, respectively). Estuaries showed the highest dominance of whooper swans among the five different habitat types, accounting for 32.13% of the population. Reservoir/lakes had 30.60% of the total population and reclaimed lakes(18.24%), river (13.11%), and coast (5.93%) followed. The annual distribution of the whooper swan population in South Korea has been affected by various habitat conditions resulting from human activities and urbanization. To better understand the complex factors that can cause rapid changes in wintering waterfowl populations, it is necessary to integrate the data from the bird census program with environmental conditions to conduct in-depth pattern analyses over longer time periods.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.542-549
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• 2021

Citrus leafminer (Phyllocnistis citrella) is an economically important pest in citrus orchards. This study was conducted to elucidate the over-wintering stage of P. citrella through experiments on the survival rate of P. citrella at low temperatures and field investigations during the winter season. There was a significant difference in the survival period depending upon the over-wintering stage of P. citrella at low temperatures, and the adults survived longer than the pupae. Evaluation of the survival period after inoculating citrus orchards with P. citrella adults and pupae showed that only the adults survived until mid-March of the following year, but all pupae died in January. This suggests that considering the fact that the germination of spring shoots in Jeju generally begins in mid-March, over-wintering adults are likely to form an early population the next year. However, pupae may not contribute to the formation of the initial population in the early season after wintering in fall shoots that are prone to freezing damage in winter because P. citrella could only survive in pupal chambers formed in fall shoots. Therefore, these results suggest that P. citrella adults that emerge in late autumn can over-winter in citrus orchards in Jeju, Korea.

• Journal of Ecology and Environment
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• v.36 no.4
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• pp.211-216
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• 2013

The purpose of this study is to examine distribution and abundance of wintering raptors in Korea during 2000-2007 which is a rare data set for covering large landscape areas. Total 6,643 raptors of 16 species were recorded at 94 different points in west, south and east coasts, and rivers of inland areas all over Korea. During the study period, the most abundant raptors were black vulture (Aegypius monachus, 62.3%), common kestrel (Falco tinnunculus, 11.0%) and common buzzard (Buteo buteo, 10.0%), and these 3 birds were dominant species in inland areas and also considered as resident species except for black vulture. Also, there was a difference among 5 different habitat types. Black vultures were most found in estuaries whereas common buzzard and common kestrel could be found in coastal areas. Presumably raptors prefer reservoirs and estuaries probably due to lower human disturbance in these areas, and management efforts should be concentrated in inland areas for black vulture and coastal areas for common kestrel and common buzzard.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.291-299
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• 2012

This experiment was conducted to investigate the effects of the addition of wintering waterfowl's feces prior to planting rice on nutrient dynamics, rice growth, and decomposition of rice straws in a controlled mesocosm. Waterfowl's feces and rice straws were placed on paddy soils in a mesocosm and the water level maintained at 5 cm. The amounts of supplied feces were 0 (control), 222, and 444 g/$m^2$. While the addition of feces showed no immediate effects, nutrients in the surface water increased in the month following treatment. Nutrients increased to a greater degree in the treatments with more feces added. Simultaneously, the decomposition of rice straws was promoted, indicating that more nutrients would be made available over time. The rice showed high productivity in the period during which nutrient level was increased, when rice needs more nutrients for the tillering stage. Therefore, the wintering waterfowl's feces could be associated with increased productivity during the growing season of rice through promoting nutrient supply and rapid decomposition of rice residue.

• Animal cells and systems
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• v.1 no.4
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• pp.571-576
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• 1997

The playas of the Southern High Plains (SHP) of Texas, USA are an important habitat for over one million wintering waterfowl. However, the recent trend toward the modification of playas for agricultural use is threatening winter habitat of waterfowl in this region. Diurnal activity budgets of wintering mallards (Anas platyrhynchos) were conducted from 1 October to 31 March, 1983-1984, and 1984-1985) at three habitat types; steep-sided pits, terraced pits, and open lakes. All seven activity patterns (feeding, locomotion, resting, comfort, courtship, alert, and agonistic) were different (P<0.05) among the three habitat types for wintering mallards on the SHP of Texas. Terraced pits supported more feeding activity (27.8%) (P<0.001) than steep-sided pits (11.2%) or open lakes (2.6%) due to their abundance of natural seeds and aquatic invertebrates. Hens (17.5%) fed more than drakes (11.7%) (P<0.05). Locomotion (32.2%) and alert (2.8%) behavior across the three habitat types showed the highest level during the early morning (6:00-9:00 AM). Paired mallards rested more (37.9%) than unpaired mallards (25.8%) (P<0.05). Agonistic activity was highest (2.4%) in terraced pits throughout the season.

• 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.

• Korean Journal of Ecology and Environment
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• v.50 no.2
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• pp.266-274
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• 2017

We surveyed the habitat use and food materials of the endangered Swan Goose (Anser cygnoides) during the wintering period at the Seocheon tidal flat. The bird wintered about six months from October 2014 to early April 2015 at the flat. They showed a remarkable change in choosing their feeding habitat and prey. They stayed entirely at sedge grass patches on Songrim tidal flat during the early wintering period (October), while after November they gradually moved to Janggu bay and used rice paddy fields as well as sedge patches on the tidal flats as their feeding site. The dietary analysis showed the sedge grass (Bolboschoenus sp., Cyperaceae) was the main dietary source during the entire wintering period. Interestingly, the proportion of Cyperaceae on feces decreased slightly over wintering time, while the proportion of Fabaceae increased relatively since November. These results suggest that the Swan Geese switched their habitat and food sources in response to the change of food availability. The Seocheon tidal flat area is the important wintering site for Swan Geese and sedge grass patches in the area need to be managed as the main feeding area for the wintering Swan Geese.