• 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.

• Journal of Forest and Environmental Science
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• v.38 no.3
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• pp.195-206
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• 2022

Gaining an understanding of bird communities in different habitat types is essential for the conservation of ecologically important habitats. Wetlands possess different types of habitats and provide an important environment for wintering waterbird communities. This study compares avian communities in five different habitat types in the Moeyungyi Wetland Wildlife Sanctuary (MWWS), Myanmar. From December 2014 to the first week of February in 2015, bird and habitat data were collected from representative areas of five habitat types (i.e., short grassland, tall grassland, lotus fields, open water areas, and rice fields) at MWWS. We established nine sampling plots in each habitat type, and used the point quadrat method to survey habitats and the point count method to survey birds in the habitats. Simple one-way analysis of variance (ANOVA) and post-hoc tests were used to determine differences between bird communities. We made 95 detections during 19 daily visits to each of the five habitat types. During the survey period, we recorded a total of 10,389 individuals belonging to 52 different bird species, based on 7-min observations at each of the 45 point count stations. Furthermore, we detected significant differences by habitat structure (i.e., vegetation coverage, height, and density; water depth; and plant species diversity) as well as bird communities (i.e., species richness, abundance, and diversity indices). In addition, the detailed analysis of 52 avian species revealed significant differences among 45 species with respect to the mean numbers of observed individuals in the survey habitats. The findings of this study revealed significant differences in the structure and composition of waterbird communities among the five assessed habitat types. Because natural marshes provide preferable habitats for a larger number and greater diversity of birds, relative to rice fields, natural marshes should be prioritized for conservation and restoration in Moeyungyi Wetland Wildlife Sanctuary.

• 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.

• Korean Journal of Environment and Ecology
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• v.21 no.1
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• pp.55-66
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• 2007

This study was conducted to analyze the distribution patterns of wintering waterbird communities in relation to local environmental factors in the urban streams of Seoul, Korea. A field survey was conducted at 66 sites of 5 tributaries and the main channel of the Hangang River in Seoul in January 2006. The total of 65 species and 39,560 individuals were recorded in the field survey. There were 48 species and 28,989 individuals in the Hangang River, 14 species and 1,395 individuals in the Tancheon stream, 15 species and 2,306 individuals in the Jungrangcheon stream, 22 species and 5,990 individuals in the Anyangcheon, 18 species and 283 individuals in the Changrungcheon stream, and 24 species and 597 individuals in Gokrungcheon stream. The dominant species were Anas platyrhynchos (22.65%), A. poecilorhyncha (14.01%), Aythya ferina (13.26%), Aythya fuligula (8.04%), and Mergus merganser (7.03%). Among the 16 species (with 30,650 individuals) of ducks, the dabbling and diving ducks were 8 species with 18,286 individuals and 8 species with 12,364 individuals, respectively. Through the principal component analysis, the study sites were classified into four main groups according to the similarity of their waterbirds' species compositions: 3 tributaries in the urban area (Group 1), 2 tributaries in the rural area (Group 2), one in the rural area, one in the urban area, the urban area in Hangang River (Group 3) and the main channel of the Hangang River in the urban area (Group 4). Species diversity index and species evenness were the highest in Group 1, while the lowest Group 2. Analysis on their environmental factors showed that the waterbirds wintering in urban streams of Seoul prefer broad water width, low water depth and broad resting sites.

• Korean Journal of Environment and Ecology
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• v.31 no.2
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• pp.135-151
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• 2017

Waterbirds were surveyed once a week from Oct. 2015 to Apr. 2016 to study the conditions of temperature of staying waterbirds on Wonju-Stream. The population staying on Wonju-Stream was in inverse proportion to the temperature change; birds increased as the temperature went down, and showed the highest peak counts on the 16th(27-Jan) survey, which was the lowest in temperature. decreasing as the temperature rose. The total population of Wonju River water birds increased with increasing freezing rate in proportion to the freezing rate of nearby reservoirs and tributaries. To clarify the relation of the numbers of the birds to temperature fluctuation, the correlation of the first period of wintering (1st~16th) and that of the later period(17th~27th) as well as the whole period was surveyed, based on the 16th which was the lowest in temperature. While most wintering waterbirds showed a negative correlation to the temperature, Egretta garzetta, Phalacrocorax carbo, and Ardea cinerea were positive in temperature relativity. Anas poecilorhyncha was in the highest relation to temperature fluctuation showing (7D/H3A(r=-0.960, P<0.000000001)) at 1-16 correlation(Cor.), with the whole wintering waterbird species showing the maximum correlation at 4D/LA in the every correlation(1~27Cor.(r=-0.942, P<0.01), 1~16Cor.(r=-0.947, P<0.01), 16~27Cor.(r=-0.958, P<0.01)). Each waterbird showed the correlation to the temperature variation(AT, HT, LT) and th duration(1D~7D) depending on the species differently. Most species demonstrated a bigger correlation to the lowest temperature rather than to the highest temperature. During the first half period of the wintering with the temperature falling it showed a high correlation to the temperature at the duration of 4D~7D, While it was for D1~D3 during the next half period.

• Korean Journal of Environmental Biology
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• v.25 no.2
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• pp.149-157
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• 2007

This study focused on patterning waterbirds occurrences at the western costal area of the Korean Peninsula in winter and relating the occurrence patterns with their environmental factors. Waterbird communities were monitored at 10 different study areas, and the composition of land cover as environmental factors was estimated at each study area. Overall dabbling ducks were the most abundant with 84% of total individuals, followed by shorebird and diving ducks. Species Anae platyrhynchos was the first dominant species, and Anas formosa was the second one. Self-organizing map (SOM), an unsupervised artificial neural network, was applied for patterning wintering waterbird communities, and identified 6 groups according to the differences of communities compositions. Each group reflected the differences of indicator species as well as their habitats.

• 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.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.4
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• pp.285-292
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• 2021

We investigated habitat use and home range of a rescued and released white-naped crane using GPS tracking technology in Cheorwon, South Korea, from October 2016 to March 2017. Four types of roosting sites were identified: frozen reservoirs, paddy fields, rivers, and wetlands. Upon arrival, the white-naped crane preferred wetlands in the Demilitarized Zone (DMZ). In late wintering season, it showed a tendency to change main roosting sites in the following order: rice paddies, rivers, and frozen reservoirs. Among 14 sleeping places, Civilian Control Zone (CCZ) with various type of available habitats was more preferred than the DMZ. Places outside of CCZ were rarely used due to anthropogenic disturbances during the night. The tracked white-naped crane widely chose daytime feeding sites while moving around all over rice paddies in the CCZ. Mean diurnal movement distance was 10.5 km with a maximum of 24.8 km. Its home range measured with Minimum Convex Polygon (MCP) and Kernel Density Estimation (KDE) was 172.30 km² with MCP, 159.60 km² with KDE 95%, 132.48 km² with KDE 90%, and 42.45 km² with KDE 50%. All estimated values of home ranges were higher in the early and later winter than those in the middle period.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.516-522
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• 2014

This study was conducted to investigate the impact of the anthropogenic factors affecting distribution of the Red-crowned Crane and White-naped Crane wintering in Cheorwon, Korea. Especially, it was investigated that the impact power and its range of the anthropogenic effect to the feeding flock density in cranes due to the paved road, residential area, military facilities and greenhouse density. The Red-crowned Crane and the White-naped Crane showed the similar preference and sensitivity against anthropogenic factors, because correlation of feeding flock density of the Red-crowned Crane and White-naped Crane was similar in the same site. The feeding flock density of the cranes near the residential area was lower than that of area far from the area, and tended to increase within 2.5 km distance. The increasing tendencies of feeding flock density from military facilities and high traffic volume road were similar, but the density in military facilities increased within 0.8 km, and the density from high traffic volume road increased within 2 km. This results suggested that military facilities and the road with high traffic volume made significant influence on foraging densities to the certain range. As the distance from the road with low traffic volume increased, feeding flock density tended to decrease. The area near the low traffic volume road had high feeding flock density because remaining rice grains were preserved by intermittent disturbances in that area. If the density of greenhouse is lower than $40/km^2$, feeding flock density in the low greenhouses density area was higher than high greenhouses density area. However, there was no difference in the feeding flock density if the density of the green houses is higher than $40/km^2$.

• Journal of Environmental Impact Assessment
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• v.24 no.4
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• pp.301-316
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• 2015

The endangered species, The Red-crowned Crane and the White-naped Crane are vulnerable species to the disturbance for human beings. We examined the importance of CCZ for the cranes by comparing the crane's density in some CCZ-released areas, which are cranes' wintering site in Cheorwon. We also assessed influence of disturbance such as construction and greenhouses on core habitats of cranes. Our study results suggested that the construction and reclamation in the CCZ shrunk core habitat area while increasing core area of far from the construction and reclamation area. The CCZ has been set since March, 2011 and the number of greenhouse has rapidly increased after 2012. As the number and size of greenhouse in the area where designation of CCZ was cancelled increased, foraging area of cranes diminished. Although the area where designation of CCZ was cancelled seemed to have more human disturbance than CCZ, the foraging density of cranes did not decline and even that of white-naped cranes increased. This could be the influence of artificial food supply at their roosting site. In conclusion, if the area of CCZ decline continuously in the future, density of cranes would decrease.