• Korean Journal of Environment and Ecology
• /
• v.23 no.5
• /
• pp.418-430
• /
• 2009

The main purpose of this study is to investigate the relationship between the topography of land and vegetation and the preferred habitat of wintering cranes. Investigations were conducted twelve times in Cheorwon basin, South Korea, during two wintering seasons (12/2005 - 2/2006; 1/2007 - 2/2007). The density of rice grain in the middle of rice paddies was higher than that of the areas along the edge of rice paddies. However it was observed that red-naped cranes preferred to feed along the edges of rice paddies rather than to feed in the middle of the paddies. White-naped cranes, on the other hand, Preferred to feed in the middle of paddies. To be more specific, red-crowned cranes preferred feeding sites such as levees of the paddies or the areas where the level of the rice beds was comparatively more elevated. But the preference of the white-naped cranes turned out to be just the opposite. Another finding was that both red-naped cranes and white-naped cranes preferred concealed areas for their feeding site, and the frequency rate of their feeding in concealed areas has little to do with weather factors. This finding contradicts a widely accepted view that cranes prefer open spaces for their feeding site. Besides, red-crowned cranes, compared with white-naped cranes, preferred to feed in more concealed areas. The frequency rate of feeding in both concealed areas and non-concealed areas had little to do with the size of feeding flocks. There was no difference between a flock of fewer than five cranes and a flock of more than five cranes in terms of frequency rate of their feeding. In conclusion, the result of these investigations indicate that red-naped cranes comparatively prefer concealed areas for their feeding site, and white-naped cranes are less prone to them, and there is no direct connection between their preference of feeding site or frequency and the size of their flock. This is presumed to be the characteristics unique to their individual species.

• Korean Journal of Environment and Ecology
• /
• v.22 no.6
• /
• pp.625-631
• /
• 2008

We used the visitation aspect of dabbling ducks(Anas spp.) to investigate the estuarine ecosystem of Nakdong River and to compare the data collected during two periods: trom May, 1989 to April 1993 and from May, 2002 to April 2006. Over for the 8 years of field surveys, 356,110 individuals from 11 species of dabbling ducks(Anas spp.) were observed in the Nakdong estuary. In the early 1990s, the average number of species gradually increased from October through November, whereas the highest numbers of species were recorded in October during the second survey period. The average number of individuals recorded during the second period was 2-3 times higher than that observed in the 1990s. Statistical analysis using a t-test indicated that the number of individuals showed significant difference at 5% level between November and February in both the early 1990s and the mid-2000s. During the winter, dabbling ducks select both estuarine wetlands as resting sites and rice paddy as feeding sites. More wintering migrants including ducks would visit to Nakdong river if we provide with enough rice paddy near the estuary. The farmland around Nakdong estuary is used by dabbling ducks as a habitat, we hope it must be conserved thoroughly. CRP(crop reserve program), implemented by the local government of Kangseo-gu, Busan City is effective in conserving rice paddy; therefore, the CRP program need to be continuously applied in the Nakdong river basin.

• Journal of Wetlands Research
• /
• v.6 no.1
• /
• pp.73-87
• /
• 2004

This study was carried out on Sihwa reclaimed area from January to December in 2003. We observed total 169,351 individuals of 70 species(22 species of waders, 9 species of egrets and 5 species of gulls). Waterbird population was the largest in March(95,465 individuals) and was the smallest from April to June(less than 7,000 individuals). The most dominant species was Pintail(Anas acuta: 58,627 individuals, 34.6%) and other species were Mallards(Anas platyrhynchos: 24.5%), Common Pochards(Aythya ferina: 13.8%), Black-tailed Gulls(Larus crassirostris: 6.1%), Spotbill Ducks(Anas poecilorhyncha: 5.0%) and Greater Scaups(Aythya marila: 2.69%). Sihwa reclaimed area supported many kinds of protected species such as Chinese egrets(Egretta eulophotes), Black-faced Spoonbills(Platalea minor), Eurasian Spoonbills(Platalea leucorodia), Mute Swans(Cygnus olor), Whooper Swans(Cygnus cygnus), and Eurasian Oystercatchers(Haematopus ostralegus). They foraged at waterside of Sihwa lake and rested at reclaimed area. Particularly, Eurasian Oystercatchers bred in habitats with Salicornia herbacea and Suaeda japonica. Reclamation of mud flats and construction of roads, transmission towers and tide embankments disturbed waterbirds in breeding and foraging. We suggest that waterbirds are protected in different action plans according to their status such as breeding, passaging and wintering birds. Maintaining of waterside and swamps in Sihwa reclaimed area will be useful for breeding waterbirds. It is needed to make a protect zone for ecological connecting belt from Oeji isarea, Hyeong isarea, Eum isarea to upper channel on Sihwa lake.

• Journal of Wetlands Research
• /
• v.21 no.2
• /
• pp.125-131
• /
• 2019

The Nakdong Estuary has experienced hydraulic and topographic changes over the last century, which have had negative effects of habitat loss and fragmentation. The population of Scirpus planiculmis, a major food plant for wintering birds in Nakdong Estuary, has decreased over the last decade. To identify factors that influence S. planiculmis population, 6 short core samples (about 30cm) were collected in June and August, 2018. The sand percentage was over 80% in every samples and the average sediment salinity in June and August were $17.8{\pm}1.12psu$ and $18.4{\pm}1.83psu$, respectively. ${\delta}^{13}C$ of sediment cores varied from -25.4‰ to -22.6‰ which fall within the estuarine particulate organic matters. In cores collected in Eulsuk area, the highest ${\delta}^{13}C$ values were observed at the surface (0~1cm) indicating inputs of marine POM (particulate organic matter) to the Nakdong Estuary. No significant difference between vegetation and non-vegetation stations was observed in every items we investigated which might indicate that the physicochemical environment of vegetation area is almost same as that of non-vegetation area. Therefore, the high sand percentage and sediment salinity of Nakdong Estuary might affect the reduction in S. planiculmis population.

• Journal of Wetlands Research
• /
• v.17 no.3
• /
• pp.264-272
• /
• 2015

Understanding bird status is essential for the systematic and sustainable management of the Nakdong River Estuary, taking into consideration the relationship between ecosystems and the bird species. In this study, bird status in the Nakdong River Estuary Bird Sanctuary prior to the Four Major Rivers Project was analyzed using the bird monitoring data (2003-2011) from surveys conducted by the Busan Development Institute. The high percentage of winter visitors in terms of both species diversity (38.36%) and individual bird numbers (63.14%) suggest that the Nakdong River Estuary is an important wintering site for migratory birds. Cumulative numbers of individual birds were higher in Myungji (208,601), West Nakdong River (202,444), Eulsukdo (153,232), and Baekhap Doyodeung (150,595). The total numbers of migratory species were higher in Eulsukdo (171), Ilungdo (124), Myungji (132), and Samrak (121). Among the 232 species found in the Nakdong River Estuary, Anas platyrhynchos (17.71%) was the most common species, followed by Anas poecilorhyncha (8.85%), Larus crassirostris (6.48%), Anser fabalis (6.09%), Anas penelope (5.16%), and Calidris alpina (4.22%). Most bird taxa, except shelducks, showed annual fluctuations in individual numbers, with increasing frequency during survey periods. Of these, cormorants, swans, and gulls showed higher fluctuations than other taxa. Swans decreased drastically in numbers in 2007-2008 and 2009-2010 compared to previous years. Shore birds, gulls, wagtails, and other forest birds were also less common in 2010-2011. These results suggest that there were some environmental changes that might have affected the birds in the Nakdong River Estuary. Overall, the results suggest that habitat types affect the distribution of dominant species.

• Korean Journal of Environment and Ecology
• /
• v.34 no.2
• /
• pp.99-105
• /
• 2020

Migratory birds use a variety of breeding and wintering sites, and it is particularly important to understand more information on breeding and feeding sites for the conservation and management of endangered species. Black-faced spoonbills (Platalea minor) are an international endangered species distributed in East Asia. The majority of black-faced spoonbills breed on uninhabited islets off the west coast of the Korean Peninsula during the breeding season, and they are distributed in East Asia such as Taiwan, Hong Kong, southern China, Japan, and Jeju island during the winter season. In this study, we used a wild animal location tracking system to analyze and compare home ranges of three black-faced spoonbills spending the post-fledging stage in Gujido islet in Incheon and Chilsando islet in Yeonggwang each in 2015. The tree black-faced spoonbills in Guji islet showed a home range in coastal areas in Hwanghaenam-do and Gangneung-gun. The home range size (mean±SD) was estimated to be 425.49±116.95 ㎢ using 100% MCP, 43.61±18.51 ㎢ using KDE 95%, and 7.46±3.68 ㎢using KDE 50%. The tree black-faced spoonbills in Chilsando islet showed a home range in the Baeksu tidal flat and the Buan Saemangeum area with a size of 99.38±55.29 ㎢ using 100% MCP, 19.87±6.05 ㎢ using KDE 95%, and 1.16±0.53 ㎢ using KDE 50%. The figured indicated that the tree black-faced spoonbills breeding in Gujido islet had a wider home range than those breeding in Chilsando islet. During the post-fledging stage, the home ranges of black-faced spoonbills were mostly breeding in mudflats. Therefore, it is necessary to minimize human intervention, such as the construction of roads and structures and the human access, to protect the habitats during the period.