• 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.

• Korean Journal of Environment and Ecology
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• v.33 no.4
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• pp.422-439
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• 2019

The rear edge population is considered to have low genetic diversity and high risk of extinction according to a highly isolated distribution. However, the rear edge population is observed to have persisted for an extended period despite the low genetic diversity. As such, it is necessary to understand the ecological process involved in the persistence of the population. Viola mirabilis L. in Korea is considered the rear edge population from the perspective of the worldwide distribution. We surveyed the distribution range of V. mirabilis, which shows the isolated distribution in the central area of Korea, to find out the factors of its persistence. Next, we investigated and accessed the vegetational pattern of habitats, soil environment, phenology, self-compatibility, population structure, and extinction risk factors observed in the distribution area. V. mirabilis was distributed in the understory of the deciduous forest, planted forest of the deciduous conifer and deciduous broad-leaved trees, shrubland, and grassland in the limestone area. We also observed the re-establishment of seedlings in the population, and most of them showed a stable population structure. For chasmogamous flowers, the visit by pollinators has a significantly positive relationship with the production of fruits. However, we found that the production of the cleistogamous flowers was more numerous in all studied populations and that only the cleistogamous flowers were produced despite a more substantial plant size in some populations. The plant size was more related to the production of the cleistogamous flowers than that of the chasmogamous flowers. Accordingly, the cleistogamous flowers significantly contributed to seedling recruitment in the population. We found that the production of the chasmogamous flowers and the cleistogamous flowers did not have a correlation with the factors of the soil analysis except for phosphoric acid. V. mirabilis showed the self-incompatibility characteristics most likely due to the production capability of the cleistogamous flowers. Potential extinction risk factors observed in the distribution area was included the development of limestone mine, the expansion of agricultural fields, and the construction of houses. Although V. mirabilis showed an isolated distribution in the limestone area in the Korean peninsula, it showed a diverse distribution in a wide habitat environment ranging from the grassland to the understory of the trees with relatively low canopy closure rate. Moreover, we concluded that the persistence of the population was possible if we can maintain the current state of multiple populations and stable population structure.

• Korean Journal of Plant Taxonomy
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• v.41 no.1
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• pp.51-57
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• 2011

The microstructure of the leaf epidermis and trichomes of Fallopia sect. Reynoutria are examined using scanning electron microscopy. Fallopia sachalinensis was distinguished from other taxa in this section by its prominent epicuticular wax layer consisting of protruding wax rodlets. In addition, epicuticular rodlets of F. sachalinensis individuals from Ullung Island and Dok Island appear to be thinner than those from other regions, including Japan and Sakhalin. The stomatal size appears to be related to the ploidy level in the sect. Reynoutria, as the hexaploids, octoploids and dodecaploids tend to have larger stomata as compared to tetraploids. Three basic types of trichomes were found in the section; (1) conical unicellular trichomes, (2) uniseriate filiform trichome consisting of 1-8 cells, and (3) peltate glandular trichomes. The trichome types and their distribution appear to be useful in distinguishing the taxa in the section.

• Korean Journal of Environment and Ecology
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• v.25 no.4
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• pp.470-478
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• 2011

Aster altaicus var. uchiyamae is on the list of endangered species in Korea. Using amplified fragment length polymorphism (AFLP) markers, we investigated the genetic diversity within and among four populations (Guram, Dori Island, Samhap, and Danyang) of A. altaicus var. uchiyamae. We also present the collecting strategies that most efficiently capture the genetic diversity of A. altaicus var. uchiyamae. Four AFLP primer combinations produced a total of 936 bands, of which 934 (99.8%) were polymorphic. A high level of genetic diversity (PPB = 45.3%, h = 0.104, I = 0.168, hs = 0.108) was recognized within the populations of A. altaicus var. uchiyamae. A low degree of genetic differentiation ($G_{ST}$ = 0.075, ${\theta}^B$ = 0.079) was detected among the populations. In addition, analysis of molecular variance (AMOVA) showed that genetic variation was greater within populations (91%) than among populations (9%). These results indicate that the high rate of gene flow has played an important role in forming the present populations of A. altaicus var. uchiyamae. According to maximization strategy, 17, 16, and 11 individuals captured all of the genetic variation in Dori Island, Samhap, and Guram population, respectively. The determination the minimum population size of A. altaicus var. uchiyamae in terms of the genetic information is critical and thereby gain reliable decision support for ex situ conservation of the endangered species, A. altaicus var. uchiyamae.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.304-312
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• 2004

The transient dynamics of three-trophic populations (prey, predator, and super predator) using ratio-dependent models responding to environmental impacts is analyzed. Environmental factors were divided into two parts: periodic factor (e.g., temperature) and general noise. Periodic factor was addressed as a frequency and bias, while general noise was expressed as a Gaussian distribution. Temperature bias ${\varepsilon}$, temperature frequency ${\Omega}$, and Gaussian noise amplitude ${\`{O}}$ accordingly revealed diverse status of population dynamics in three-trophic food chain, including extinction of species. The model showed stable limit cycles and strange attractors in the long-time behavior depending upon various values of the parameters. The dynamic behavior of the system appeared to be sensitive to changes in environmental input. The parameters of environmental input play an important role in determining extinction time of super predator and predator populations.

• Korean Journal of Environment and Ecology
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• v.35 no.1
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• pp.48-67
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• 2021

Plant species exhibit current characteristics as a result of interactions with environmental conditions. The plants of Viola sp. have selected chasmogamous flowers with vigorous vegetative propagation or development of cleistogamous flowers as an adaptation strategy. Viola websteri is distributed on the Korean peninsula and the eastern part of Jilin Province, China. The center and edge of the distribution are expected to exhibit different population-dynamics. It is necessary to investigate the cause of its current limited distribution even though V. websteri has a mixed-mating strategy. Firstly, We examined the vegetation environment of habitats and evaluated its characteristics. Growth characteristics were examined through plant phenology. We then evaluated the population structure, characteristics of chasmogamous flowers, and productivity of cleistogamous flowers. Moreover, we compared population sizes between 2014 and 2018. Most habitats were located in deciduous broadleaf mixed forests adjacent to valleys. V. websteri produced chasmogamous flowers with self-incompatibility in April-May and cleistogamous flowers in June-September. The cleistogamous flower production is a strategy ensuring seed production under uncertain environmental fluctuations; these were approximately twice as numerous as chasmogamous flowers. The population structure was distinguished into stable and very unstable regions. There were sites where the population experienced a sharp decline in the 2018 compared to that of 2014. This large decline was found in the edge populations. The habitats had different microsites depending on the natural disturbances of drought and the matrix constituting the habitat, thus supporting various plants. Ensuring the production of seeds through cleistogamous flowers, it was determined that rapid seedling re-establishment and population replenishment were possible when the natural disturbance factor was removed. Environmental factors did not equally affect all populations or individuals. Therefore, it was expected that it would be able to persisted in a long time, despite the rapid decrease in the number of individuals in the population regionally. Local extinction and re-establishment are likely to repeat according to environmental change. We propose the additional population investigation based on this works are required. We also suggest a need to assess the long-term population dynamics and the genetic characteristics of chasmogamous flowers and cleistogamous flowers to establish and implement effective conservation strategies.

• Korean Journal of Environmental Agriculture
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• v.32 no.4
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• pp.294-303
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• 2013

BACKGROUND: It is well known that rice-fields can provide excellent foraging places for birds including seasonal migrants, wintering, and breeding and hence the high biodiversity of rice-fields may be expected. However, how environmental change including climate-changes on life-history and population dynamics in birds on rice-fields has not been fully understood. In order to investigate how climate-change affects population migratory patterns and migration timing, I modeled a population dynamics of birds in rice-fields over a whole year. METHODS AND RESULTS: I applied the Lotka-Volterra equation to model the population dynamics of birds that have been foraging/visiting rice-fields in Korea. The simple model involves the number of interspecific individuals and temperature, and the model parameters are periodic in time as the biological activities related to the migration, wintering and reproduction are seasonal. As results, firstly there was a positive relationship between the variation of seasonal population sizes and temperature change. Secondly, the reduced lengths of season were negatively related to the population size. Overall, the effects of the difference of lengths of season on seasonal population dynamics were higher than the effects of seasonal temperature change. CONCLUSION(S): Climate change can alter population dynamics of birds in rice-fields and hence the variation may affect the fitness, such as reproduction, survival and migration. The unstable balances of population dynamics in birds using paddy rice field as affected by climate change can reduce the population growth and species diversity in rice fields. The results suggest that the agricultural production is partly affected by the unstable balance of population in birds using rice-fields.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.375-383
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• 2023

To determine the cause of the population decline in Gobiobotia naktongensis, substrate preference and burying behaviour were investigated in this study. In general, the species was shown to prefer a substrate size of 1 mm or less, depending on the flow. In addition, the burying depth varied according to the size of the fish and increased with a decrease in water temperature. Our findings showed that the main cause of the population reduction was the physical changes in the substrate structure due to the dams or barrages construction. Notably, the accumulation of silt and mud in the substrate upon the formation of an upstream lentic water region for structural construction and bed armouring caused by scouring and reduced downstream inflow of fine sediment were deterministic in the fish habitat changes, causing problems in burying. As sand substrate structure is critical for the survival and inhabitation of psammophilous species, efficient strategies should be developed with proper habitat management to reduce the anthropogenic damage

• Journal of Korean Society of Forest Science
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• v.108 no.2
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• pp.168-176
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• 2019

To understand the floristic composition, vegetation structure, and population dynamics of Koelreuteria paniculata communities, which are native to Daegu, South Korea, a field survey was conducted in July 2018 using phytosociological and complete enumeration methods. Based on information on vegetation and trees of >5 cm diameter at breast height collected during the field survey, we classified the community types by species composition and analyzed their vegetation strata, relative importance value (MIV), life forms, species diversity, and population structure. The community was divided into the following three types: Ulmus parvifolia-Vitex negundo var. incisa subcommunity, Securinega suffruticosa subcommunity, and Clematis apiifolia community. The vegetation unit system was organized into one community group, two communities, and two subcommunities. Vegetation coverage of the tree layer was >85%, while the herbaceous layer was <10%. MIV of K. paniculata appeared to be extremely high within all vegetation strata, with 94.3 of the tree layer, 81.6 of the subtree layer, 75.5 of the shrub layer, and 60.0 of the herbaceous layer. The species diversity (H') was significantly different among the community types, and the C. apiifolia community (2.062) was approximately four times higher than the S. suffruticosa subcommunity (0.547). The overall representative life form types were "$MM-R_5-D_4{\cdot}D_2-e$,", but there were some differences in the disseminule form among the community types. The population structure of K. paniculata showed the reverse J-shaped distribution with a high density of young individuals and low density of larger individuals among all three community types, and because no plant species within the lower vegetation could replace K. paniculata, it was considered to be a sustainable population.

• Korean journal of applied entomology
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• v.39 no.1
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• pp.43-52
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• 2000

A portion of mitochondria1 COI gene (438 bp) was sequenced from the sampls of Plutella xylostella from four localities in Korea to investigate the population genetic structure and characteristics by measuring the magnitude of genetic diversity and the degree of gene flow among populations. Thirteen haplotypes ranging in nucleotide divergence 0.3% to 1.4%, were obtained from 21 individuals. The nucleotide divergence was similar to the other related studies, but haplotype diversity was substantially higher (mean h = 0.81). The genetic distance among geographically remote Cheju Island population and the two Kimhae populations, distant 1 lkm to each other, was not statistically significant (p<0.05). Instead, a substantial or high female gene flow was detected (Nm = 2-30). One Hawaiian haplotype of the diamondback moth obtained through GenBank search also was genetically similar to the ones obtained from this study. Collectively, the genetic population structure of the diamondback moth in Korea can be characterized into two aspects. First, the diamondback moths in Korea possesses overall moderate genetic divergence based on a high number of haplotypes. Second, a high haplotype diversity within each population due to the long distance dispersal with a substantial dispersal power and the resultant genetic similarity among geographic populations is characteristic.