• Journal of Ecology and Environment
• /
• v.43 no.3
• /
• pp.282-288
• /
• 2019

We investigated the changes in the population size and inter-specific space usage for breeding in mixed breeding sites of the great cormorant (Phalacrocorax carbo), grey heron (Ardea cinerea), great egret (Ardea alba modesta) and intermediate egret (Egretta intermedia) in Gammul-myeon, Goesan-gun, Chungcheongbuk-do, South Korea, in 2016-2017. These species bred in two adjacent habitats (site A and site B). The number of breeding pairs of all species and the size of the breeding area at site B increased in 2017. In 2017, great cormorants at site B occupied the breeding sites previously occupied by the other species in 2016, while the grey heron and great egret occupied the sites around the great cormorant breeding site. The heights of nest trees and nests of great cormorant and grey heron did not differ temporally, but these heights in site B were significantly higher than those in site A for great cormorants. For great egrets, these greatly decreased in site B in 2017. Thus, the great cormorant either moved to favourable nest sites for breeding success or selected nest sites used by the herons in the previous year. Further studies of these two possibilities are necessary.

• Journal of Crop Science and Biotechnology
• /
• v.11 no.3
• /
• pp.193-198
• /
• 2008

To develop a natural re-seeding technology, the optimum soil incorporation time of Chinese milk vetch(CMV) plant residues, seed persistence in soil, biomass production and subsequent rice yield were determined from 2005 to 2007 in rice with CMV green manure in southern Korea. Generally, insufficient seedling stand was regenerated with CMV incorporation to the soil at 20 and 25 days after flowering(DAF), while high regeneration of greater than 400 seedlings per $m^2$ was observed at 35 and 40 DAF. High re-seeding stand of CMV incorporated at 35 DAF or later was related with high seed viability and heavy seed weight. Appreciable number of CMV seeds remained 4 month after burial in soil and a good number of CMV seedlings regenerated from this seed bank at rice harvest time in the fall. Based on the relationships among re-seeding number of CMV plants, seed weight and seed viability, CMV plants should be incorporated into the soil 35 DAF(May 30) or later when CMV seeds were sufficiently matured. The natural re-seeding stand for the 3-year trials was stable ranging from 437 to 700 plants per $m^2$ and the biomass production was sufficient to supply nitrogen for rice growth. The use of re-seeding CMV plant can produce similar rice yield like that of rice without CMV green manure.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.3 no.3
• /
• pp.165-171
• /
• 2022

The Chinese crested tern (Thalasseus bersteini) is one of the most globally endangered species, listed as "Critically Endangered (CE)" on the IUCN Red List, with only approximately 30-49 individuals surviving in the wild. Chinese crested terns were discovered to breed in South Korea for the first time in 2016 while conducting a census on uninhabited islands. The Ministry of Environment has declared the breeding habitat of the Chinese crested terns as "Specified Island" to protect this CE species. However, brown rats (Rattus norvegicus) inhabiting the breeding grounds of the Chinese crested terns and Black-tailed gulls may potentially pose a threat to the breeding of these avian species. Therefore, we conducted a study on the feeding behavior of brown rats involving stable isotope analysis to determine their food sources. Fecal analysis showed that brown rats mainly fed on plants, whereas they scarcely fed on animals, such as insects. In addition, the stable isotope analysis showed that the δ¹³C values of brown rats, insects, and Indian goosegrasses were approximately -16 to -11‰, whereas the δ¹³C value of Chinese crested terns that obtained their food from the marine ecosystem was approximately -22 to -18‰. Hence, we conclude that the source of carbon for brown rats on this island is the terrestrial ecosystem. We ruled out the possibility of any direct prey-predator interaction between the brown rat and the Chinese crested tern or Black-tailed gull.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.2 no.4
• /
• pp.279-284
• /
• 2021

The dung beetle, Gymnopleurus mopsus (Coleoptera: Scarabaeidae), is one of endangered species in South Korea. It was last recorded in 1971. To restore this species, we introduced G. mopsus populations from eastern and southern regions of Mongolia in July 2019 and August 2019, respectively. One of the main tasks for the restoration of endangered insects is to develop breeding techniques to eventually incorporate these insects into the restoration system. In a series of laboratory experiments, we investigated effects of short-term hibernation periods on life-history traits of G. mopsus. Adult G. mopsus that had hibernated for 30, 60, and 90 days had lower survival rates than adults that had hibernated for 120 days. We also compared developmental time of these four experimental groups and found a significant difference in the egg - phase. However, the duration of hibernation did not affect the fecundity, brood-ball size, or body size of F1 adults. Follow-up studies are currently being conducted to further investigate the effect of a short-term hibernation period on population growth of G. mopsus under laboratory conditions.

• Journal of Ecology and Environment
• /
• v.29 no.1
• /
• pp.69-74
• /
• 2006

The captive breeding biology of the Oriental white stork (Ciconia boyciana) was studied over 3 breeding periods. Both the male and female participated in nest building, but the male started to build the nest earlier and spent much time. Time used to build the nest was steadily increased to the egg laying. The copulations were observed $30{\pm}10.53$ (n=3) times in a breeding period. Both male and female incubated their eggs but the female spent more time than the male did. The chicks were hatched $32{\pm}1.29$ (n=6) days after egg laying. Not only the male but also the female took part in the rearing chicks. The male spent more time than the female as chicks grew. The results of this study are useful to assess the ecological soundness of the breeding pair and facilitate the breeding environment in captive breeding of the Oriental white stork.

• Korean Journal of Environment and Ecology
• /
• v.22 no.3
• /
• pp.332-337
• /
• 2008

This study was conducted to clarify the differences in bird communities in breeding season between coniferous forests of Mt. Namsan and Gwangneung areas from April to August 2006. We chose a study site of 10ha in size for territory mapping of breeding bird community in each area. There were significant difference in DBH distribution of trees and average foliage profiles between both study areas. Number of breeding species and pairs, breeding density, and bird species diversity were higher in Gwangneung area than in Mt. Namsan area. Number of bird species and breeding pairs belonged to hole and canopy guild were different between both study areas. The difference in breeding bird communities between both study areas may be related with forest structure. For the protection and management of birds, greater structural complexity would be needed in Mt. Namsan area.

• Proceedings of the Korean Society of Environment and Ecology Conference
• /
• 2006.10a
• /
• pp.98-102
• /
• 2006

We studied the behavior of black vultures breeding in Erdenesant, Mongolia through time budget observation. We observed a pair of black vulture for 115 days from April 30 to August 22, 2005, of which 15 days were before hatching and 100 days of brood rearing. The egg hatched on May $14^{th}$. Incubation was done by both a male and female vultures, but the period covered by the male vulture(56.82%) was longer than that by the female one(34.62%). In the early days of brood rearing, time spent by the female vulture at the nest took 54.9 % and it was 19.27% for the male. In the middle of brood rearing period, just inaction and preening were noticed, as they watched their chicks for a long time without sheltering chick under the parent's body. Late brood rearing period was characterized by less chick care and adults mostly stayed in the nest only when to feed the chicks. During breeding time, both the male and the female vulture fed only the chicks and did not give food to each other. During rearing period, the male vulture fed the chick more often than female.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.3 no.3
• /
• pp.129-138
• /
• 2022

Reintroduction programs have been promoted across the world to recover and rehabilitate endangered birds through ex situ captive breeding and releasing to the nature. The ultimate aims of these reintroduction programs are recovery of sustainable populations in natural habitats. To ensure the success of the reintroduction programs, it is necessary to examine the followings in order to increase the success rate of releasing along with the development of captive breeding techniques: 1) Adequate habitat provision, 2) adaptability of captive-bred individuals, 3) survivability of released individuals, and 4) social interest and will. Before releasing captive-bred individuals, it should be reviewed whether there are habitats in which the limiting factor is removed, and assessed their long-term safety. The quantity and quality of the released individuals must be considered to increase the chances for mate selection, maintain genetic diversity, and acquire the ability to adapt to the wild. The release method must be decided in consideration of characteristics of the target habitats and individuals, and rational means such as careful observation, evaluation, and feedback must be provided throughout the release process. For the long-term success of recovery projects, social awareness, sustainable support, and related experts are needed. Satisfying these criteria can help to increase the success rates of reintroduction programs. For the bird reintroduction program in the future, the feasibility of the methods and procedures must be closely reviewed before starting.

• Korean Journal of Environment and Ecology
• /
• v.27 no.6
• /
• pp.666-675
• /
• 2013

This research was carried out from March 2009 to July 2012 to explicate the height change based breeding-ecological characteristics of Titmice that were breeding in the artificial nests installed in the Halla Mountain. The first egg-laying day was delayed as the height of the area under investigation increased, and it turned out that the decrease in temperature due to the elevated height had influence on that delay (p<0.05). Generalizing the annual results of the analyses, we see that there was no significant correlation occurring between the average temperatures and egg-laying days in the breeding season (April~June) (p>0.05). The rate of artificial nest use was not different among areas and among year, but between the species, Parus major and Parus varius. There were differences in clutch sizes among species (p>0.05), but no differences in heights and years (p<0.05). The hatching-, fledging-, and breeding-success rates were 67.3%, 99.5%, and 67.0% respectively in 2011, and 71.3%, 96.8%, 69.0% respectively in 2012, from which we can tell that the fledging-success rate was high but the hatching- and breeding-success rates were similar. Though we confirm that temperature changes due to height differences had influence on breeding periods, but we cannot identify a significant correlation with other breeding-ecological characteristics. Thus, in order to more precisely explicate the influence of temperature changes due to heights on Titmice's breeding, long-term research is needed in terms of the investigation of microclimatic factors and food resource.

• Ecology and Resilient Infrastructure
• /
• v.7 no.4
• /
• pp.388-395
• /
• 2020

Exotic species have been imported for economic purposes, but more recently, an increasing number of animals are imported as pets. With the increasing popularity of two species of turtles, Mauremys sinensis and Pseudemys concinna, the number of pet turtle owners has gradually increased since 2014. The number of turtles increased by 180 in 2017 and 281 in 2019. However, these turtle species have been abandoned to nature, owing to their long lifespans and the changes in conditions of pet owners. The two turtle species have been designated as invasive alien species (AIS) in Korea considering their ecological risks, and the Biological Diversity Act prohibits their release. The owners of Mauremys sinensis and Pseudemys concinna are required to submit the "Application for Approval of Breeding and Grace for AIS" document. In this study, the breeding conditions for the two turtle species were investigated by analyzing the information in the submitted applications for six months (e.g., the suitability of breeding facilities, number of turtles, breeding period, type of pet adoption, and local district of pet owner). A total of 614 cases were analyzed. Because only 58% of breeders provided suitable breeding conditions, breeding information and responsible pet ownership training should be offered to prevent abandonment in natural ecosystems. In addition, continuous monitoring is necessary to prepare for potential problems caused by the lack of information in many applications and the one-off licensing policy.