• Korean Journal of Ecology and Environment
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• v.51 no.2
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• pp.192-203
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• 2018

Headwater streams provide various microhabitats, resulting in high diversity of macroinvertebrate community. In this study, we compared the differences of communities between two adjacent headwater streams (Jangjeon stream (GRJ; GRJ1-GRJ5) and Haanmi stream (GRH; GRH1-GRH3)) in Jungwang and Gariwang mountains, Gangwon-do and evaluated the effects of habitat condition to the macroinvertebrates community composition. In order to characterize the macroinvertebrate communities and extract influential environmental factors, we applied to Cluster analysis (CA), Indicator species analysis and Non-metric multidimensional scaling (NMDS). Total 33,613 individuals in 3 phyla, 5 classes, 13 orders, 51 families, and 114 taxa (genera or species) were collected. Gammarus sp. was dominant at the upper stream of GRJ, whereas Chironomidae spp. was abundant at GRH and the downstream of GRJ. The CA classified samples into six clusters (1-6) reflecting spatial and temporal variation of benthic macroinvertebrate communities. Benthic macroinvertebrate community composition was significantly different between two adjacent streams. Sweltsa sp. 1, Psilotreta kisoensis, Rhyacophila shikotsuensis and Serratella setigera were identified as representative indicator species for clusters 1, 2, 3 and 5, respectively. Similar to CA results, NMDS revealed the spatial and temporal differences of benthic macroinvertebrate communities, indicating the difference of community composition as well as microhabitat condition. Forest composition, proportion of boulders (>256 mm), and water velocity were main factors affecting the macroinvertebrate community composition.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.378-384
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• 2019

Red-eared slider, Trachemys scripta elegans, is one of the most famous species to disturb native ecosystems in the world. In South Korea, the species was imported as pet, and now it is found whole of the country. Recent, natural breeding and spreading of the turtle has been reported. In this paper, we investigated the environmental factors to affect the reproduction of T. s. elegans. We surveyed the distribution of the turtle in Jeju island, South Korea, between 2012 to 2017. We compared the land covers and climate of habitats from breeding sites and non-breeding sites. The species was found from 38 sites in Jeju island; 21 of breeding sites and 17 of non-breeding sites. The number of total and only adult turtles was significantly higher in breeding sites than non-breeding sites (P<0.05). In breeding site, the reproduction rate from the farmland was significantly higher than others(P<0.05). However, the rate of land covers was not significant in non-breeding site (P>0.05). The difference on the climate between breeding and non-breeding was not significant(P>0.05). Moreover, none of climate factors affected to reproduction of T. s. elegans(P>0.05). Our study showed that the land covers surrounding the habitats are more important than climate for reproduction of T. s. elegans in Jeju island. This result indicates investigating the habitat and surrounding is necessary for the control of reproduction and spreading of the introduced species.

• Korean journal of applied entomology
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• v.50 no.2
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• pp.97-105
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• 2011

Understanding the metapopulation structure and movement of a species are required for conserving the species. In this paper, migration patterns and connectivity of patches of a threatened butterfly, Parnassius bremeri Bremer, were postulated using the mark-release-recapture (MRR) technique in a habitat located in the mid-southern region of the Korean peninsula. A total of 194 individuals were captured (137 males and 57 females) and, of them, 93 individuals (73 males and 20 females) were recaptured during the MRR experiment. The migration analysis showed 23-150% immigration and 28-53% emigration. There were high correlations between the migrating individuals and the distance between patches, but there was no correlation between migrating individuals and patch size or between migrating individuals and the number of host plants. Consequently, the migration of butterflies occurred frequently between closer patches, while patch size and quantity of the food plant had minor effects on migration behavior. Additionally, males migrated more frequently than females. Analysis of the migration patterns of P. bremeri showed that the central patch played an important role on linking patch groups and more frequent migrations were monitored between nearby patches than between the remote patches. This study suggested that active migrations take place between the neighboring multiple patches and these are accelerated if there is a stepping-stone patch between them.

• Korean Journal of Environment and Ecology
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• v.25 no.1
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• pp.10-16
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• 2011

This study was carried out to analyze the vegetation and soil characteristic, and ordination of the Ilex cornuta population, in the Yongsu Reservoir of Jeju Island. The Ilex cornuta population was classified into Cudrania tricuspidata dominant population, Sageretia theezans dominant population, and Mallotus japonicus dominant population. In the study sites, soil organic matter(O.M.), total nitrogen(T.N.), available phosphorus($P_2O_5$), changeable potassium, changeable calcium, changeable magnesium and soil pH were 14.62~17.35%, 0.39~0.51%, 8.83~20.15mg/kg, 0.44~0.64cmol+/kg, 5.79~6.87cmol+/kg, 3.43~4.19cmol+/kg and 5.41~5.80, respectively. The Mallotus japonicus dominant population was mainly found in the high percentage of available phosphorus, organic matter. It was also showed the lowest concentration of exchangeable K, and Mg. Cudrania tricuspidata dominant population and Sageretia theezans dominant population were found in the low percentage of available phosphorus, organic matter and there were also showed the highest concentration of exchangeable K, and Mg. It is one of the evidence that Ilex cornuta community indicated an intensive site management likes clearance of creeper is proper habitat management protocol. Thus, further researches should be followed to determine the other disturbance factors as management techniques.

• Korean Journal of Environment and Ecology
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• v.23 no.6
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• pp.553-563
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• 2009

This study was conducted to analyze the changes in the echolocation of Pipistrellus abramus according to environmental characteristics. The survey was conducted in the day-roosting site of P. abramus located in Gyeongju City (North Gyeongsang Province) from April to August, 2009. The environmental characteristics during the research were classified in six categories: the emergence time after sunset moving time from day roost to feeding areas; rice fields; forest edges; open spaces; and residential areas. Analysis results showed that there are differences in environmental characteristics and also differences between the moving time to the habitat and the moving time to capture preys. At the emergence time from day roost, Pipistrellus abramus used a FM signal with a short pulse-duration. In open spaces, however, they used a CF signal with a long pulse-duration. In different environmental situations, they used both FM and CF signals, although the types of pulse which they used were different. Except pulse-duration, there were significant differences in pulse-interval, peak-frequency, starting-frequency and ending-frequency between the movement among habitats and the movement to capture preys. Except the emergence time from day-roost, they showed a narrow band FM signal and a long pulse-duration that are suitable to search for insects by sensing echoes of insects when they moved among their habitats. When they were out to capture their preys, they showed a broad band FM signal and a short pulse-duration which enabled them to widely search and accurately locate their preys.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.1
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• pp.114-118
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• 1997

Effect of water temperature, salt and $MgCl_2$ concentration on sand ejection characteristics of short neck clam, Luditapes philippinarum was investigated. Unlike other shell fish such as red shell, arkshell and surf clam, treatment of short neck clam with sea water was evaluated not effective as sand ejection conditions. Sand ejection activity of short neck clam was shown effective at $2.5\%$ NaCl (pH 8.0) at $25^{\circ}C$. This activity was enhanced about 1.57 times when 50 mM $MgCl_2$ were added to the above mentioned conditions. But the extent of sand ejection activity was shown higher in the order of sea water $(3.2\%\;salt)+20mM\;MgCl_2$, sea water $(3.2\%\;salt),\;2.5\%\;NaCl+50mM\;MgCl_2$, treatments. Therefore, it was suggested that habitat conditions and Mg ions could be responsible for biological activity and concominant sand ejection of short neck clam.

• Korean Journal of Plant Taxonomy
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• v.42 no.4
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• pp.253-259
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• 2012

The genetic variation in populations of Eranthis byunsanensis, an endemic and rare species of Korea, was studied using starch gel electrophoresis. All five known populations were sampled for allozyme electrophoresis of nine enzymes coded by 10 loci. The overall genetic variation of E. byunsanensis population was shown to be considerably high within the populations (A = 2.4, P = 90.0, $H_E$ = 0.311). A positive $F_{IS}$ value of E. byunsanensis indicated an overall deficiency of heterozygotes, and a low $F_{ST}$ value (0.131) showed little differentiation among populations. The high genetic variation, less genetic differentiation among populations, and a significant amount of heterozygote deficiency propose the hypothesis that they have an experience of recent isolation and fragmentation of their habitat. Thus, the rate of gene flow has been drastically reduced, and the rate of inbreeding in E. byunsanensis populations has increased. Current habitats in Mai-san and Naro-do are vulnerable due to their small population size and the levels of anthropogenic activity in the region constantly threatening survival of this species. Because of the high genetic variation and low levels of differentiation among populations in E. byunsanensis, it is not issue which populations have a priority for protection, but we may concern the plan to maintain population continuously and diminish the rate of inbreeding.

• The Korean Journal of Malacology
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• v.18 no.1
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• pp.53-59
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• 2002

The distribution and density of the pen shell, Atrina (Servatrina) pectinata japonica, were investigated to estimate population ecological parameters and biomass. Samples were collected during cruises from April to June 1999 in the coastal waters of Chungchung-namdo, Korea. The oceanographic conditions such as depth, temperature, transparency and suspended solids were measured from sampling stations. Seawater depth ranged from 3.9 m to 75.9 m and the mean was 28.5 m (SE = 0.97). The mean density of the pen shell was higher in the depth of 18.0-30.8 m. The water temperature of the bottom ranged from 7.0-21.5$^{\circ}C$ and the mean was 14.$0^{\circ}C$. The transparency ranged from 1.2-13.5 m and the mean was 4.8 m. The suspended solids ranged from 6.0-93.5 mg/l and the mean was 48.0 mg/l. The sand proportion of the sediment was > 50%. The mean densities of the pen shell by sediment type were 7.3 individuals/40 m$^2$ (SE = 2.16) in the sand, 5.6 individuals/40 m$^2$ (SE = 1.48) in the muddy sand, 3.0 individuals/40 m$^2$(SE = 1.89) in the sandy mud, and none in the mud. The sandy bottom, accounting for 29.8% of the overall habitat area, had a maximum density of 7.3 individuals/40 m$^2$.

• Journal of Environmental Science International
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• v.22 no.9
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• pp.1227-1234
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• 2013

Between July and October 2011, radio-tracking was used to analyze the characteristics of home ranges and day roosts of Myotis aurascens by using 3 individuals (male: 2, female: 1). Bat capturing was conducted at a bridge and a nearby forest in Ulju-gun, Ulsan-si. We attached radio transmitters (0.32 g) to the bats and monitored them by using a radio receiver with a Yagi antenna. Home-range analysis of M. aurascens by using 100% minimum convex polygon (MCP) and 95% MCP showed an average of 106.5 ha and 89.3 ha, respectively, and 50% kernel home range (KHR) showed an average of 8.4 ha. Home range overlap of the 3 bats was observed at the bridge and at nearby water bodies as the core areas, and the size of the home range overlap was 7.3 ha by 100% MCP, 5.9 ha by 95% MCP, and 1.6 ha by 50% KHR. The home range for each bat consisted of the main foraging sites, and the types of foraging sites were similar. M. aurascens-01(M-01) used the bridge and nearby water bodies as the nightly main core areas, M. aurascens-02(M-02) used rice fields and water bodies adjacent to the forest as core areas, and M. aurascens-03(M-03) used water bodies and resident areas as core areas. Although rice fields and resident sites represented the core areas of the home ranges of M-02 and M-03, habitat use was the highest near water bodies as the core area for all the 3 bats. The types of day roosts in this study were a wooden house, canopies of a broad-leaved woodland, and banks of rice fields. The roosts in the wooden house and canopies of the broad-leaved woodland were located within the forest, and the roost in the banks of rice fields was also adjacent to the forest. Our results revealed that the main home range and foraging sites of M. aurascens were located near water bodies as the core area, and forests and places adjacent to the forests were used as day roosts.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.462-468
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• 2004

Most of the surveys of periphyton carried out for environmental and ecosystem health assessment of streams have considered the impact made on their fixative substrates (stones, rocks, sand, silt, clay and other abiotic matters), but there has been virtually no research that considered moving substrates. This study attempted to make an analysis and assessment of the habitat environments of the microalgae attached to the skin surfaces of fish living in small streams, with a focus on their species composition and community structure. The dominant fish in the this survey were Zacco temmincki and Zacco platypus, which are usually found in the streams, and rivers, and they accounted for 62% and 19%, respectively, in relative abundance. Substrates of fish, a representative organism with the trait of moving a long distance, show a marked contrast with those of organisms fixed at a certain place. Characteristics of both the upstream and the downstream reach well reflected in the microalgae attached to the skin surface of fishes, of which diatoms took the major composition. The result of this observation is considered to be useful to provide basic data in assessment of stream health. Also it may be suggested as a biological tool for the assessment of aquatic environment in the future.