• Korean Journal of Ichthyology
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• v.22 no.1
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• pp.49-55
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• 2010

Sympatric sites of type NE and NS of Zacco korean us were found in the upper reaches of many tributaries of the Nakdong and Seomjin rivers, as well as in some streams draining into the South Sea, Korea. In streams where the two types exist together, there was a tendency for individuals of NE to densely populate the upper reaches and those of NS to populate the middle reaches. A habitat-segregation phenomenon was observed in the cohabiting sites. Fishes of NE preferred rapids, whereas fishes of NS preferred slowly flowing or lentic regions. It seemed that the number of NE was proportional to the flow velocity, but NS showed an opposite trend in the cohabiting sites. On the other hand, such tendency was not found in regions where NE and NS exist separately.

• Korean Journal of Environment and Ecology
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• v.29 no.2
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• pp.210-220
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• 2015

We quantified temporal and spatial changes in the habitat for fish populations, the distribution of mandarin fish(Siniperca scherzeri) and an introduced species, largemouth bass(Micropterus salmoides) in Lake Paro and inflowing streams. The number of fish species identified in Lake Paro and the tributary streams included 10 families, 24 species and 10 families 30 species, respectively. The dominant fish species in Lake Paro were Zacco platypus, Hemibarbus labeo, Squalidus gracilis majimae, S. scherzeri and Tridentiger brevispinis, Z. platypus, Z. koreanus, and S. gracilis majimae in the inflowing streams. Although the habitat segregation for S. scherzeri and M. salmoides occurs, these two species showed the use of the fishes of the family Gobiidae as an important prey item based on IRI analysis. S. scherzeri and M. salmoides preyed mainly on T. brevispinis(67.4 %) and R. brunneus(84.0 %), respectively. The species preyed on by S. scherzeri and M. salmoides were benthic fishes that inhabit shallow water depths around the lake and have little swimming ability.

• Journal of Ecology and Environment
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• v.43 no.3
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• pp.320-331
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• 2019

Background: Dioecious plant species having both male and female plants have been investigated regarding sex-related characteristics such as sex ratio, sex-differential resource requirements, and spatial segregation of the sexes. Habitat loss and fragmentation are major threats to the survival of plant populations, but dioecious species are particularly more prone to such habitat degradation than non-dioecious species because of their dimorphic sexual system. We examined the sex-related demographics of two Ilex cornuta populations being different regarding land use history. Methods: During 2016-2017, we examined I. cornuta trees with a basal diameter ${\geq}1.5cm$ in the Yongsu-ri population (YS population) and the Gotjawal Provincial Park population (GP population). Plant sex (male, female, or unsexed) was identified. The tree size (basal diameter and height of the main stem), clonal production (the ramet numbers per genet), and vitality for each clone were measured. The associations between population, sex, tree size, clonal production, and vitality were examined using ANOVAs and contingency table analyses. Finally, point pattern analyses using O-ring statistics were conducted to assess spatial patterns. Results: Upon excluding unsexed trees, the YS population with 74 trees was significantly male-biased (0.66), while the GP population with only 26 trees had a 1:1 sex ratio. In both populations, males and females did not differ in tree size. Although the mean number of ramets differed significantly between populations, females tended to produce more ramets than males. The proportion of weak trees was significantly higher in the YS than in the GP population. Neither population showed evidence of spatial segregation of the sexes. Conclusions: The two populations of dioecious I. cornuta are characterized by the small number of trees and relatively high frequencies of non-reproductive trees. Both indicate that these populations are quite susceptible to environmental and genetic stochasticity. On the other hand, the differences between populations in sex ratio, clonal production, and vitality suggest that conservation efforts for I. cornuta need to be population-specific. In order to help recover and enable this vulnerable species to persist, it is necessary to find ways to enhance their sexual reproduction and simultaneously reduce habitat disturbances due to anthropogenic activities.

• Mycobiology
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• v.49 no.3
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• pp.235-248
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• 2021

This study aimed to understand whether the geo-ecological segregation of native plant species affects the root-associated fungal community. Rhizoplane (RP) and rhizosphere (RS) fungal microbiota of Sedum takesimense native to three geographically segregated coastal regions (volcanic ocean islands) were analyzed using culture-independent methods: 568,507 quality sequences, 1399 operational taxonomic units, five phyla, and 181 genera were obtained. Across all regions, significant differences in the phyla distribution and ratio were confirmed. The Chao's richness value was greater for RS than for RP, and this variance coincided with the number of genera. In contrast, the dominance of specific genera in the RS (Simpson value) was lower than the RP at all sites. The taxonomic identity of most fungal species (95%) closely interacting with the common host plant was different. Meanwhile, a considerable number of RP only residing fungal genera were thought to have close interdependency on their host halophyte. Among these, Metarhizium was the sole genus common to all sites. These suggest that the relationship between potential symbiotic fungi and their host halophyte species evolved with a regional dependency, in the same halophyte species, and of the same natural habitat (volcanic islands); further, the fungal community differenced in distinct geographical regions. Importantly, geographical segregation should be accounted for in national culture collections, based on taxonomical uniqueness.

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.241-249
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• 1994

Leaf diffusive resistance (LDR), stomatal density, length of guard cell and hair density of leaves of 6 oak species were determined under withdrawal of water, and their strategies of drought stress were analyzed by principal component analysis. LDR of Quercus acutissima, Q. aliena and Q. serrata increased earlier than those of the other species at high leaf water potential $({\Psi}_{leaf})$ or low water saturation deficit (WSD), which was an avoidance mechanism reducing damage by water stress. Q. variabilis with low stomatal density, small stomatal size and high hair density had avoidance mechanisms increasing LDR at high $({\Psi}_{leaf})$ However, Q. mongolica and Q. dentata increased LDR at low $({\Psi}_{leaf})$ as xeric species do. Results from principal component analysis on the 15 variables related to strategies of drought stress indicated that the 6 oak species were divided into 2 groups: (1) Q. acutissima, Q. aliena and Q. serrata as mesic habitat species and (2) Q. variabilis, Q. mongolica and Q. dentata as xeric habitat species. Among three xeric species Q. acutissima differed from the other two species in the drought strategies such as high hair density, low stornatal density, high leaf area ratio, stomatal closing at low $({\Psi}_{leaf})$ and small cell wall elasticity. The results could reasonably explain their drought strategies in natural habitat.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.2
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• pp.37-59
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• 2017

The Korean peninsula belongs to the temperate forest biome dominated by many deciduous oaks. We quantitatively and qualitatively studied vertical and horizontal distributions and habitat characteristics on the major oak species such as Quercus mongolica, Q. serrata, Q. variabilis, Q. dentata, Q. aliena and Q. acutissima. A total of 5,278 samples were analyzed with a species coverage and 6 principal environmental variables extracted from public database of nationwide natural environment survey. Correlation analysis was accomplished by the CANOCO using Canonical Correspondence Analysis and the Pearson correlation coefficient using PASW Statistics. The hierarchical distribution tendency of six oaks was finalized using the Goodman-Kruskal lambda coefficient of non-metric multidimensional scaling by SYN-TAX 2000. The utmost factor on the distributional segregation of oak species was the elevation, i.e. temperature. Q. serrata and Q. mongolica show clearly a diametrical distribution patterns with zonal distribution. Q. variabilis was determined as a thermophilic and xerophilous species that is a component of not only natural pseudo-climax forest but also secondary forest. The highest frequency of the dominant forest was found Q. mongolica. Whereas, Q. serrata showed the highest frequency of individual tree but the relatively lower frequency of dominant forest, which is resulted from the original habitat loss. By the benefit of the traditional Soopjeong-E, Q. acutissima dominant forests were remained rather largely. Individuals of Q. dentata occurred horizontally nationwide, but its dominant forest was the poorest. Dominant forest of Q. aliena, which is a natural vegetation, was the most rare due to a limited potential habitat.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.270-272
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• 2002

Competitive species have the same spatial distribution (habitat) and foraging behavior (niche), while non-competitive species have either different feeding behavior or spatial distribution. Therefore, ecological segregation among species of fish results rfom differences in foraging behavior and spatial distribution (Allen, 1984; Zhang 1988). To explore these ecological strategies among major small fish pelagics in Korean waters, distribution of CPUE in the Korean large purse seine fishery were examined. (omitted)

• Animal Systematics, Evolution and Diversity
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• v.4 no.2
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• pp.91-102
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• 1988

Both Cobitis lutheri Rendahl and C.striata Ikeda previously regarded as the subspecies of C.taenia are revised here and raised to the species rank based on the distinct color pattern on their body sides in relation to the shpae of lamina circularis and suborbital spine, and distinct distributional patter. C. lutheri was similar to C. striata in chromosome number and karyotype, but chromosomal polymorphism as Robert sonian event was confirmed only in the population of C.lutheri studies. Both, C. kutheri and C..striata have disjunct ranges : the former in western Korea and east-northern China Mainland, the latter in the Smjin River of korea and west-southern Japan. hybridization between C. lutheri and C. striata by secondary contact appeared in the limited zone of the Dongjin River, Chllabuk-do province, korea, but the evidence for habitat segregation between them suggests the possibility that natural hybridization occurs between the two species and introgression results. We consider that the two species were produced as ecological equivalent species in the different branch stream of the Paleo-Hwangho River , The time of recession of sea level during the gracial period.

• Journal of Ecology and Environment
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• v.35 no.2
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• pp.111-122
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• 2012

The sex ratio and spatial structure of different sexes are major components that affect the reproductive success and population persistence of dioecious plants. The differential reproductive costs between male and female plants are often believed to cause a biased sex ratio and spatial segregation of the sexes through slower growth and/or lower female survivorship. In this study, we examined the sex ratio and spatial structure of one population of $Torreya$ $nucifera$ trees in Jeju Island, Korea. We also tested the effects of the current tending actions in relation to tree vitality. At the population level, the sex ratio of the 2,861 trees was significantly biased toward males; however, it also showed considerable variation among different diameter at breast height classes and across habitats according to terrain level (from upper to lower). In 1999, before tree management (tending) began, among the ecological traits examined, only climber coverage correlated with tree vitality. Intensive tending such as climber removal since 1999 clearly enhanced the vitality of the majority of trees, but its effects were more conspicuous in medium-sized trees than in small ones, in upper terrain trees than those in other terrains, and in females than in males. Both male tree domination in small and large trees and tending effects on females are likely to reflect the effects of female reproductive costs regarding growth and/or survivorship. Spatial segregation between males and females was not observed in $T.$ $nucifera$. Habitat heterogeneity created by the forest's rocky ground and its implications regarding sex ratios and spatial structure require further studies.

• Journal of Plant Biology
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• v.17 no.2
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• pp.87-94
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• 1974

This survey has been carried out on ten species(Erythronium japonicum, Symplocarpus renifolius, Adonis amurensis var. ramosa, Corydalis turtschaninovii var. genuina, Primula sieboldii forma spontanea, Anemone raddeana, Gagea Iutea, Heloniopsis japonjca, Hylomecon japonicum, and Convallaria majalis var. keiskei in the undergrowth of a forest of deciduous broad-leaved trees in the Kwangnung area of Kyung-Ki Province. They always bloom towards the end of March which is earlier than most of the other plants do. They completely finish up their matter productions before foliage of the deciduous trees, which are the upper strata plants, grows broader or to cite in other terms, before the relative light intensity in the lower strata is fallen to the lowest degree to become to insufficient to allow for photosynthesis. These phanerophytes naturally wither down between June and July. The above mentioned phenomenon clearly demonstrates a kind of the ecological niches and habitat segregation in terms of using sunlight to her greatest advantage. Soon after these herbs wither they make their own winter buds-life form-around their roots and then go into hibernation. The intensity of light in this forest zone was measured through the use of a lux meter in order to investigate it's seasonal variations. In additions, an intensive survey on the duration of their efflorescence was fullfilled.