• Korean Journal of Environment and Ecology
• /
• v.15 no.3
• /
• pp.267-275
• /
• 2001

This study was conducted to investigate the characteristics of bird community and to suggest a proper way how to manage and protect bird community in Mt. Paldal, Suwon City. The survey was carried out by line transect method from March 1992 to February 1993, and from October 1998 to August 1999. Twenty-seven birds were recorded, and these birds were also classified into 14 species for residents, 8 species fur summer visitors, 4 species for winter visitors and 1 species fur passage migrant in 1992. Twenty-one birds were recorded, and these birds were also belonged to 16 species fur residents, 2 species fur summer visitors, 2 species for winter visitors and 1 species for passage migrant in 1999. In 1992, seasonal change of number of species and individuals showed a typical pattern of temperate deciduous forests, however, seasonal pattern in 1999 was somewhat differed from that of temperate deciduous forest. According to data of migration habits of bird community in same months, percentage of residents were higher in 1999 and that of summer visitors were higher in 1992. In guild analysis of breeding bird community, bush-nesting and foraging guild that utilize the bush layer as nest and food resources showed the decreasing number of species and individuals, also summer visitors did the same decreasing trends from 1983. Therefore, it should be suggest that protection of bush layer for inhabitation of bush-nesting and foraging guild and summer visitors, and it will be considered that construction of green net-work among urban forests such as Mt. Kwanggyo, Mt. Chilbo, Mt. Paldal, Mt. Sukgi and Mt Yeogi in Suwon City.

• Journal of Embryo Transfer
• /
• v.32 no.3
• /
• pp.177-182
• /
• 2017

This study was conducted to investigate the ovarian cycle changes of the mare according to the season. Twenty four Jeju crossbred horses(Thoroughbred ${\times}$ Jeju horse) raised in Subtropical Livestock Research Institute, National Institute of Animal Science, RDA were used to identify follicles and corpus luteum with ultrasonography once a week(May 2016~June 2017). Blood samples of experimental horses were collected twice a week for analysis of P4 hormone levels. The mares were considered to have resumed ovarian cyclicity on the day of ovulation if they followed by regular ovarian cycles. Only 13 cases(61.9%) of the total 21cases showed normal ovarian cycle, and 8 cases (38.1%) showed delayed ovarian cycle. Three cases(16.7%) in October, 5 cases(27.8%) in November and 5 cases(27.8%) in December(27.8%) ceased the heat and the remaining 5 cases(27.8%) showed that the estrus was maintained in winter. Horses that stopped estrus ceased the heat until March of next year, and 27.8% were continued the heat during non-breeding season. Eleven cases(61.1%) of 18 cases in April and 2 cases(11.1%) of 18 cases in May returned the estrus.

• Journal of Animal Science and Technology
• /
• v.46 no.1
• /
• pp.31-38
• /
• 2004

Data from five Hanwoo breeding farms were collected to analyze the effects of parity, season, nutrition and reproduction on body conditions of heifers and cows and to analyze the relationships of body conditions with reproductive performances and body growth. Analytic models included farms and parity which were run through SAS to estimate least squares means and correlation coeflicients between traits body condition scores(BCS) of I(very emaciated) through 9(very obese) scale at service and at calving. calving interval, days to rebreeding, gestation length. number of services per conception. Overall averages were 4.55 for BCS at service, 5.42 for BCS at calving. 406.7days of calving interval, 287.7days of gestation length, 66.2days from calving 10 first service and 1.78 times of services per conception. Number of services per conception was 1.50${\sim}$1.74 times for the cows of BCS 5 or under and 2.00${\sim}$3.00 for those of BCS 6 or higher. Body weight of calves from cows observed averaged 23.3kg at birth and 70.7kg at weaning. 57 percent of cows showed BCS 4${\sim}$5 at service while 46 percent of those showed 5${\sim}$6 at calving. Estimated phenotypic correlation coefficients of BCS at service with BCS at calving, calving interval, gestation length, number of services per conception were low but positive: 0.16, 0.26. 0.08 and 0.06. respectively. Phenotypic correlations of BCS at calving with calving interval, gestation length and number of services per conception were estimated to be also low and positive: 0.10, 0.13 and 0.10. respectively. However, phenotypic correlations between calving interval and gestation length, and between gestation length and number of services per conception were negative but low as - 0.11 and- 0.13 each.

• Korean Journal of Environment and Ecology
• /
• v.22 no.6
• /
• pp.648-657
• /
• 2008

This research was conducted to investigate the breeding density and seasonal food items of the magpies in Jeju Island and the near-manned islets. The examination of nest distribution to determine breeding density was performed during breeding season from February 2006 to April 2008, and that of food items from May 2006 to February 2008. A total of 2,113 nests were found across Jeju Island, the average density was $1.33\;nest/km^2$, and the magpies were distributed up to 600 meters above the sea level. The nest density was the highest in the central areas of Jeju Island, with 688 nests at $3.61\;nest/km^2$, while that in the eastern areas was the lowest, with 214 nests at $0.66\;nest/km^2$. In terms of the number of nests depending on the height above the sea level, 1,172 nests, which was equivalent to the density of $1.85\;nest/km^2$, was observed below 100m and highest among the intervals of height, but 16 nests found at 500-600m were the lowest, corresponding to $0.20\;nest/km^2$. The number of nests found in the manned islets near Jeju Island was eight in Biyang-do with the density of $15.38\;nest/km^2$, nine in U-do with $1.49\;nest/km^2$, and one in Gapa-do with $1.15\;nest/km^2$, whereas none of nests were observed in Mara-do. The contents of stomach consisted of 17 types of prey sources including countless bones, eggshells, plants, and seed, most of which were the individuals of the order Coleoptera. In spring and summer, the foraging frequency for invertebrate animals such as insects was high, but less than 30% in winter. In contrast, the magpies preyed upon plants and seeds at the frequency of 10% and 30%, respectively, in spring, while the foraging frequencies for both of them were 100% in winter and higher than any of other seasons. Eggshells and bones of birds were also detected infrequently. If the density of the magpies, which may play role as the upper predator within the ecosystem, increases, it would be expected to affect directly the reduction of the number of the species and population of endemic animals such as small birds and reptiles, etc. Therefore, it is considered that long-term monitoring for the density of the magpies and precaution is prerequisite to minimize adverse effects on ecosystem.

• Korean Journal of Environmental Biology
• /
• v.21 no.2
• /
• pp.149-157
• /
• 2003

This study focused on relationships between Pb and Cd concentrations and the difference of success reproductive progress in urban (Seoul) and industrial complex (Ansan) areas. Results of the Pb analysis for the feral pigeons from Seoul (egg contents:1.64 $\mu\textrm{g}$ wet $g^{-1}$, adults in bones: 29.5 $\mu\textrm{g}$ wet $g^{-1}$ and the Ansan industrial complex (egg contents: 1.13 $\mu\textrm{g}$ wet $g^{-1}$, adults in bones: 10.5 $\mu\textrm{g}$ wet g-1) showed that the Pb level of eggs and adults is significantly different between the two colonies (p<0.05). Cd concentrations in liver and kidneys of adult pigeons were also significantly different between Seoul(liver: 0.24 ${\mu}g$ wet $g^{-1}$, kidney: 1.05 $\mu\textrm{g}$ wet $g^{-1}$ and the Ansan (liver: 0.14 $\mu\textrm{g}$ wet $g^{-1}$, kidney: 0.43 $\mu\textrm{g}$ wet $g^{-1}$ colonies (P<0.05). Clutch size of Feral Pigeons living in Seoul was similar between the two colonies, 1.9$\pm$0.3 in Seoul and 2.0$\pm$0.0 in Ansan. The length, breadth, and thickness of eggs were not significantly different between the two colonies (p>0.05). Incubation period in Seoul (17.8 days) did not differ from the Ansan (17.4 days). No difference in growth rate (body weight, wing length, and tarsus length) was found between the two test groups (p>0.05). In Seoul, 65.2% were hatching, and 42.1% fledging. The Proportion of hatching and fledging in the Ansan was 60.7% and 45.0%, respectively. The significant differences between the two colonies for reproductive sucess were not found (p>0.05). With regard to the reproductive effects to the heavy metals, the Pb and Cd concentrations feund in the two colonies were not as high as those considered in results of toxic effects in other species.

• Applied Microscopy
• /
• v.31 no.1
• /
• pp.19-35
• /
• 2001

Outlines for plasma $estradiol-17\beta$, components, electrophoretic patterns, and ultrastructural changes were obtained in female rainbow trout (Oncorhynchus mykiss) during the seasonal reproductive cycles. Plasma $estradiol-17\beta$ under the natural conditions, exhibited distinct seasonal variation, peaking very late in vitellogenic season during September, decreasing gradually the halt of spawning in December, and ultimately falling during the early stages of seasonal ovarian recrudescence in February and March. This change in $estradiol-17\beta$ appeared to stimulate vitellogenin production as evidenced by increases in plasma calcium, phosphorus, glucose, albumin and total protein levels. The electrophoretic patterns of late maturing or spawning oocytes were stained more intensively than those of late perinucleolus oocytes (molecular weights of approximately 70,000 and 200,000). Two protein bands were found in the SDS-PAGE separation, coincident with the $estradiol-17\beta$ hormone peak. Gonadosomatic indices (GSI) significantly increased from October to January, and showed the highest peak in January, coinciding with the numerically abrupt increase of ripe ova in female. A positive correlation (r=0.701, p<0.01) was established between plasma $estradiol-17\beta$ levels and the gonadosomatic index during the prespawning. The highest level of hepatosomatic index (HSI) observed in December. During the breeding season (December), the gonadotropes were large and filled with GTH-containing inclusions such as granules and globules. The vitellogenic phase began as late perinurleolus oocytes became transformed into early maturing oocytes through the accumulation of yolk, and oocytes reached the late maturing stages as the ooplasm was completely packed with yolk. Marked ultrastructural changed in the granulosa cells during nuclear migration involve the dilation of the rough endoplasmic reticulum and the appearance of the rod-shaped mitochondria with tubular cristae. Microvilli (finger-like projections), from the zona radiata and from the oocyte grew, and made contact with each other in the pore canals of the zona radials during vitellogenesis, but were withdrawn as the zona radiata became more compact and devoid of pore canals during oocyte maturation. The zona radiata grew to a tripartite structure such as an outer thin homogeneous layer, and two inner thick helicoidal layers (zona radials interna and zona radiata externa). Under the normal conditions, the ovarian follicle influenced the histological development and periodical secretion of the hormones , sufficient for a oogenesis and gonadal steroid production.

• Korean Journal of Environment and Ecology
• /
• v.6 no.2
• /
• pp.180-192
• /
• 1993

This study was conducted to investigate bird community and to suggest a proper way how to manage and protect bird community in Sobaeksan National Park. The survey was carried over 3 main trail districts by line transect method to figure out influence factor of inhabitation of wild birds from February to October in 1992. The study results as follows: The observed birds were belong to 9 orders l2 families 58 species, they also have Sparrow Hawk dccipiter nisus, Kestrel Faleo tinnunculus(natural monument no. 323). Scops Owl I'otus scops(natural monument no. :324), Black Woodpecker Dryoaepus martius(natural monument no. 242. R). White-backed Woodpecker Dendroaepos leuotes(R) and Gray-backed Thrush Turdus hortulorum(R). These birds a]so classified into 31 species for residents. 17 species for summer visitor, 6 species for winter visitor. 4 species for passage migrant, respectively. Species richness was 38 species at spry, 33 species at summer. 26 species at autumn and 22 species at winter. The density was 3.00 ea /ha at spring, 2.37 ea /ha at summer, 3.62 ea /ha at autumn and 2.88 ea /ha at winter. Breeding bird community in Sobaeksan National Park was dominated by Hole, Bush-nesting guild and Canopy-foraging guild. Natural vegetation of 900m altitude in 1st section and the grassy plain in 2nd section are to be protected absolutely for the habituation of wild birds. Species richness in 3rd section was higher than any other section owe to a various habitat such as valley. open lands, orchid, farm land and forest etc. Food plants and broad-leaved forest is to be managed for the provision of opulent food resources in autumn and winter, user is to be managed for the successful propagation of wild birds in spring and autumn.

• Korean Journal of Animal Reproduction
• /
• v.23 no.3
• /
• pp.183-189
• /
• 1999

A study was conducted to estimate the effects of parity of dam, sex, year and season of birth on gestation length and birth weight in Korean native and Yanbian yellow cows. A total of 1,206 reproduction records (587 Korean native cows, 619 Yanbian yellow cows) were collected from Daekwamyeong Branch Institute, National Livestock Research Institute in Korea and Yanbian region in China from 1995 to 1998. The least square means for gestation length and birth weight of Korean native cows and Yanbian yellow cows were 287.3$\pm$0.60 and 282.3$\pm$0.80 days, 24.9$\pm$0.25 and 25.2$\pm$0.24kg, respectively. Gestation length and birth weight were increased significantly as parity of dam progressed in Korean native cow(p＜0.01), but were not significant in Yanbian yellow cow. Birth weight of male calf was heavier than that of female calf in Korean native cow and Yanbian yellow cow(p＜0.01). Gestation length of Korean native cow born male calf was longer than that of Korean native cow born female calf(p＜0.01), but was not significant in Yanbian yellow cow. Effect of birth year on birth weight was significant in Korean native cow and Yanbian yellow cow(p＜0.01), but effect of birth year on gestation length was not significant. Birth weight of spring-born calf was the heaviest and that of fall-born calf was the smallest in Korean native cow and Yanbian yellow cow(p＜0.01).

• Korean Journal of Ecology and Environment
• /
• v.50 no.1
• /
• pp.116-125
• /
• 2017

Alpine plants with a scarcity of pollinators in harsh environments have been believed to undergo selfing for reproductive assurance; however, contradictory evidence is also available. Snowmelt regimes in alpine areas function to change life history characteristics of alpine plants such as flowering time and duration; yet the effects of snowmelt regimes have never been tested in alpine plants in Korea. This study was conducted to investigate the dichogamy, mating systems, and flowering characteristics of Megaleranthis saniculifolia populations [early and late snowmelt plots (ESP and LSP, respectively)] in a subalpine area of Sobaeksan Mountain in Korea. M. saniculifolia exhibited incomplete protogyny in that despite early maturation of pistils, maturation times of pistils and stamens within flowers were partly overlapped. Control and hand-outcrossing treatments produced significantly higher number of follicles and seeds per flower than autonomous and hand-selfing treatments. Based on the aggregate fruit set, the auto-fertility index (AI) and self-compatibility index (SI) were 0.33 and 0.50, respectively. Snowmelt occurred 10 days earlier in ESP than in LSP, thereby ESP and LSP showed distinct differences with regard to flower longevity and season, but showing no difference in peak flowering dates. We concluded that M. saniculifolia is an incomplete protogynous and largely outcrossing plant requiring pollinator service. Temporal variation in snowmelt time and subsequent changes in flowering characteristics under climate change may further threaten the population persistence of M. saniculifolia which has already been designated as endangered species in Korea.

• The Korean Journal of Malacology
• /
• v.28 no.2
• /
• pp.175-185
• /
• 2012

To clarify reproductive ecology of the melania snail Semisulcospira coreana (v. Martens, 1886) in Bukhan River, gonad development, fatness, gonad index, sex ratio, first sexual maturity of population, monthly change of larvae number and developmental stages in brood pouches were investigated by six identification methods. As maturation progrsses, the sex of the snali can be distinguishable easily by color:: the ovary being blue-green and testis light yellow. The sex ratio of female to male individuals over 13.95 mm shell height was significantly different from 1:1 (${\chi}^2$ = 38.45, p < 0.05). The sex ratio of female to male individuals changed drastically according to the season, Based on the monthly variations of fatness, gonad index and histological analysis, spawning occurred twice a year (spring and autumn) and the mean size of matured eggs was $450{\mu}m$ in diameter. The monthly change of larval number in brood pouch showed also two distinct peaks in March and September during the year. The average number of larvae in brood pouches was 286 - 862 individuals. In this study, the number of larvae in the brood pouches were a minimum in December and a maximum in March (975 larvae). The biological minimum size (the size at 50% of group sexual maturity) of the melania snail was 13.95 mm in shell height in females and males. All females over 15 mm in shell height possesed brood pouches.