• Journal of Environmental Impact Assessment
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• v.22 no.5
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• pp.525-528
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• 2013

River otter(Lutra lutra) are listed as endangered species and Natural monument in Korea, and this study examined the possibility of extinct of river otter in Hongchon river using with the application of Population Viability Analysis (PVA) technique. In Hongchon river areas population was estimated 9 individuals for the last 1999-2005 years and PVA analysis was done for the next 10 years using the average population of 9. Using the initial population the river otter was estimated 30% of extinct for the next 10 years. This estimation was quite low considering water pollution and construction of highways. Also PVA only used population size lacking in other life history information. Nonetheless river otter population can be in risk of extinction if the current construction of crossovers, cement bank are maintained. Long term information regarding life history needs essential.

• Journal of Environmental Impact Assessment
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• v.18 no.5
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• pp.293-299
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• 2009

Wintering migratory species of white-fronted geese (Anser albifrons) are common visitor in South Korea, and this study examined the survivorship of white-fronted geese in the Junam Reservoir with the application of Population Viability Analysis (PVA) technique. In Junam PVA analysis was done for the next 50 years using factors of breeding population, sex ratios, survivorship in the VORTEX program. As a result white-fronted geese will reach to carrying capacity within 40 years, and population will reach to carrying capacity later when it becomes smaller. Also with a large initial population white-fronted geese will reach to carrying capacity earlier. In conclusion, for the next 50 years the white-fronted geese are expected to a long-term survival with stable condition with survivorship (0.03) and extinction rate (0.0).

• Journal of Wetlands Research
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• v.18 no.3
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• pp.282-285
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• 2016

Peregrine falcon (Falco peregrinus) are listed as endangered species and Natural monument #323 in Korea, and this study examined the possibility of extinct of peregrine falcon in Jang Hang wetland near Han river using with the application of Population Viability Analysis (PVA) technique. In Jang Hang wetland areas population was monitored during 1999-2005 averaging 10.8 individuals and PVA analysis was done for the 5 years (2015-2020) using the average population size. Using the initial population was estimated 20% of extinct rate during the time. This estimation was quite low considering water pollution and loss of habitat. Also PVA only used population size lacking in other life history information. Nonetheless falcon population can be in risk of extinction if the current construction of crossovers in the river, cement bank are maintained. Long term information regarding life history needs essential.

• Korean Journal of Environmental Biology
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• v.30 no.4
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• pp.307-313
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• 2012

The Oriental White Stork (Ciconia boyciana) is a representative wetland species distributed across East Asia. The species has been declined to face the threat of species extinctions with estimation of at about 3000 individuals. In order to re-introduce the endangered storks in the field, we developed a baseline model using the program VORTEX, performed sensitivity test, and finally suggested an ideal model based on results of the sensitivity test. The baseline model predicted 12.5% extinction probability with mean time to first extinction of 82.0 year. Sensitivity test revealed that two demographic variables (first-year mortality and percent of adult female breeding) had the greatest impacts on population persistence. Thus, corrected model improved the population persistence, where the extinction probability decreased to 1.0% in 100 years by changing values of two variables within a range of applicable to the population. Our models for stork re-introduction suggest this population will be stable by improving first-year mortality and adult female fecundity.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.73-81
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• 2009

Population viability analysis of a Gold-spotted pond frog (Rana chosenica) population at Cheongwon-gun, Chungbuk, in South Korea was conducted and we proposed several suggestions for effective conservation and re-introduction of the species. Simulating a developed model over 1,000 times predicted that the population will exist over 30 years with a relatively low growth rate of 0.113, but with a high probability of extinction as 81.1%. Population growth and extinction probability were the most greatly depended on the rate of successful metamorphosis. In the case of outbreak of amphibian diseases such as Chytridiomycosis and Ranavirus, the population will be easily extinct within 4 years with 100% probability. In a habitat of which carrying capacity is 200, to successfully re-introduce an extinct population, it is initially needed to put 100 individuals of which 83% is males and its age structure is normal-distributed. If we additionally conducts artificial supplementation of 10% individuals every 2 years from 4 years to 10 years after initial reintroduction, the population will become a stable with 0.297 growth rate and 0.290 extinction rate. Our results are the first case of amphibian population viability analysis in Korea and could be used to develop effective conservation and re-introduction plans for endangered Gold-spotted pond frog.

• Korean Journal of Environment and Ecology
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• v.27 no.4
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• pp.417-428
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• 2013

The red fox (Vulpes vulpes), listed as a Class I endangered species by the Ministry of Environment of Korea, has been considered to be extinct in South Korea since the 1980s, and an intensive restoration project has been underway in Sobaeksan national park. This study was carried out to develop a suitable model for the red fox reintroduction program based on Population viability analysis (PVA) by using the VORTEX program. If 10 animals (5 females and 5 males) were continuously released into the initial zero population every year for 10 years, population growth rate and extinction probability over the next 50 years after the introduction of the population were $0.018{\pm}0.204$ and 0.354, respectively; the maximum population size was 116.34 at the 16th year after the first release, and a reduction rate of 1.22 every year from the 17th year was inferred. We found that additional releases would be needed from the 17th year after the initial release to maintain a positive growth rate and to prevent the extinction of the released red foxes, and releasing more than 12 individuals every year would be needed for the long-term, continuous existence of red foxes. By contrast, if fewer than 6 red fox individuals were released the extinction probability over the next 50 years was more than 80%. To maintain the minimum population growth rate, the release of more than 8 individuals were needed for positive population growth. The population growth rate was more stable when 10 animals in the change of their sex rate every year from the set value were released as the female-to- male sex ratio of 6:4 rather than 1:1. However, if the female-biased sex ratio was increased by more than 7:3, a negative population growth was expected. The occurrence rate of roadkill and poaching are important factors in the red fox restoration project. The extinction probability was decreased to 30% if each factor was decreased to 3% based on the standard baseline; however, if each factor was increased to more than 3%, an extinction rate of about 90% was reached over the next 50 years.

• Korean Journal of Environment and Ecology
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• v.35 no.5
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• pp.548-557
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• 2021

Cypripedium japonicum Thunb. is an endemic plant in East Asia, distributed only in Korea, China, and Japan. At the global level, the IUCN Red List evaluates it as "Endangered Species (EN)," and at the national level in Korea, it is evaluated as "Critically Endangered Species (CR)." In this study, we investigated the characteristics of the age structure and the sustainability of the population based on the data obtained by demographic monitoring conducted for seven years in the natural habitat. C. japonicum habitats were observed in 7 regions of Korea (Pochoen, Gapyeong, Hwacheon, Chuncheon, Yeongdong, Muju, Gwangyang), and 4,356 individuals in 15 subpopulations were identified. The population size and structure differed from region to region, and artificial management had a very important effect on the size and structural change of the population. Population viability analysis (PVA) based on changes in the number of individuals of C. japonicum showed a very diverse tendency by region. And the probability of population extinction in the next 100 years was 0.00% for Pocheon, 10.90% for Gwangyang, 24.05% for Chuncheon, and 79.50% for Hwacheon. Since the above monitored study sites were located within the conservation shelters, which restricted access by humans, unauthorized collection of C. japonicum, the biggest threat to the species, was not reflected in the individual viability. So, the risk of extinction in Korea is expected to be significantly higher than that estimated in this study. Therefore, it is necessary to reflect population information in several regions that may represent various threats to determine the extinction risk of the C. japonicum population objectively. In the future, we should expand the demographic monitoring of the C. japonicum population known in Korea.