• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.322-330
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• 2018

Herbivory is a major functional component of forest ecosystems, and herbivorous insects comprise about 25% of all insect species. Increasing plant diversity is related to herbivore abundance and diversity, which affects the level of leaf damage caused by insects. This study was conducted to identify plant-related variables such as plant diversity and number of leaves and density-related variables, basal area, and diameter at breast height (DBH) in a temperate forest of southern South Korea. To assess the level of leaf damage caused by leaf chewing insects, we set up two 0.1 ha plots in a temperate deciduous forest on Mt. Jirisan National Park. Plant richness differed between two sites: 16 species in 14 families(site 1) and 19 species in 15 families (site 2). Fisher's alpha index based on plant species richness and abundance resulted in 4.41 (site 1) and 6.57 (site 2). However, the sum of basal area of each site was higher in site 1 ($6.6m^2$) than site 2 ($3.7m^2$). The total surveyed leaves at two sites were 3,832 and 4,691, respectively and the damage leaves were 1,544 and 2,136, respectively. The mean leaf damage level was 11.2% (${\pm}1.76%$) in two study sites: the leaf damage level of the site 1 (11.99%) was significantly higher than site 2 (10.59%). Stepwise regression analysis showed that species diversity and evenness were the significant variables for leaf damages by chewing herbivores. NMDS ordination also identified that high tree density and low species diversity were the significant variables. This suggested that the level of damage was significantly higher in plots with low plant diversity and high tree density. In the future, we will investigate other guilds of herbivores such as sap-suckers, miners and gallers in temperate deciduous forests.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.159-165
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• 2023

This study measured the ecological niche overlap between two deciduous oak species(Quercus acutissmia and Q. dentata) according to the change in growth responses after treating with the moisture and nutrient contents of the soil at four gradients, and interpreted the degree of competition between the two oak species by ordination method. In the moisture environment gradient, the ecological niche overlap of the two species was high in the photosynthesis-related leaf organs and low in plant architecture such as shoot length. In addition, in case of competition between two oaks, Q. dentata was remarkably dominant in soil moisture gradient, but Q. acutissimia slightly was slightly advantageous over Q. dentata in the soil nutrient gradient. These results show that even in a similar taxonomical group growing in a similar habitat, the response to the organ system of the plant varies depending on the type of environment factor, resulting in different competitive differences among plants.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.201-212
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• 2021

In wetland protection areas, a phytosociological research was conducted on willow forests, which plays an important ecological and environmental role and is the main material for ecological restoration. A total of 61 relevés were collected according to the Z-M(Zürich-Montpellier) school's method and the characteristics of plant communities and the composition of the species were identified. A total of 9 plant communities including 237 taxa were differentiated. Willow species showing the high r-NCD(relative net contribution degree) value in study areas were Salix koriyanagi, Salix chaenomeloides, Salix triandra subsp. nipponica, Salix gracilistyla and Salix pierotii. Poaceae was the most diverse in species, followed by Asteraceae, Apiaceae, Polygonaceae and Fabaceae. Life form type of willow forests in wetland protection areas was determined to be Th(therophytes)-R₅(non-clonal form)-D₄(clitochores)-e(erect form) type. The naturalized plants and invasive alien species were identified as 24 taxa and 4 taxa, respectively. Naturalized and disturbance indices were 10.1% and 41.4%, respectively. The results of the site-species ordination by Non-Metric Multidimensional Scaling(NMDS), wetland types and altitude gradient were the main ecological factors determining the spatial distribution of plant communities. Diversity index and evenness index were high in mountainous palustrine wetlands with relatively high altitude, and the disturbance index, naturalized index and appearance rate of annual plant were high in riverine and lacustrine wetlands with low altitude.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.3
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• pp.211-218
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• 2007

In this study, we investigated the spatial distribution of macrozoobenthos in the estuarine sandy flat, the Bongam tidal flat located in Masan Bay during March, 2004. A total 13 species were identified at 12 stations within the tidal flat. The mean density was $20,267\;ind./m^2$, and mean biomass was $228.1g/m^2$. Dominant species in the Bongam tidal flat were all polychaetes: Prionospio japonicus ($11,716\;ind./m^2$, 57.8%) and Polydora ligni ($3,929\;ind./m^2$, 19.4%) of spionoid polychaete, and Neanthes succinea ($3,425\;ind./m^2$, 16.9%) of nereid polychaete. The most dominant species, P. japonicus distributed evenly all stations in the tidal flat. But N. succinea showed high density at the upper area of the tidal flat. Species diversity index (H') was in the range of 0.6 to 1.2 which is relatively low due to the prominent of P. japonicus and few species richness at each station. The study area was divided into two station groups (group A and B) based on the cluster analysis and MDS ordination, and the spatial distribution of macrozoobenthos on the Bongam tidal flat seemed to be in the influence of exposure duration from tidal levels and specific geological topography.

• Korean Journal of Environmental Biology
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• v.26 no.4
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• pp.385-391
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• 2008

In Korea, Quercus acutissima distributed in good condition with high nutrients and moisture content, but Quercus variabilis in dry soil or rock habitate. In order to understand this ecological distribution of Q. acutissima and Q. variabilis, we cultivated the seedlings of two oak species treated with light, soil moisture and nutrient gradients each four level, from May to October in glass house. Then we measured the ecological niche breadth and niche overlap of the two species, and analyzed the relationship of competition using cluster analysis and PCA ordination. Ecological niche breadths of Q. acutissima under moisture and nutrient treatments were slightly wider than those under light one. Among 14 characters measured, 6 characters related with length items were wider in all the environmental treatments, but 8 characters connected with weight terms narrower in light treatment. Ecological niche breadths of Q. variabilis under moisture and nutrient treatment were wider than those of light one. Ecological niche of Q. acutissima was wider than those of Q. variabilis in all the environmental treatments. Ecological overlap between two species was higher with a range of 0.87$\sim$0.92, especially higher in soil moisture factor. These results means that Q. acutissima is more competitive than Q. variabilis, especially in soil moisture condition. Two species were ordinated with distinct group based on 9 characters. From these results, it can be explained that what Q. variabilis distributed in bad soil condition is due to the escape strategy, because of its low competitive ability to Q. acutissima in natural communities.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.426-436
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• 2012

This study was carried out to investigate actual vegetation, the structure of plant community, and ecological succession sere of coastal forest ecosystem in warm temperate climate zone, Taejongdae, Busan City, Korea to provide the basic data for planning of the forest management. As a result of analysis of actual vegetation, vegetation types divided into 35 types, and the area of survey site was $1,750,461m^2$. The ratio of vegetation type dominated by Pinus thunbergii was 80.7%, dominated by Quercus spp. was just 5.0%, and dominated by Carpinus tschonoskii was just 0.4%. Eighteen plots(size is $20m{\times}20m$) were set up and the results analyzed by DCA which is one of the ordination technique showed that the plant communities were divided into four groups which are community I(P. thunbergii community), community II(P. thunbergii-Quercus serrata community), community III(Q. serrata-P. thunbergii community), and community IV(Carpinus tschonoskii-P. thunbergii community). The age of community I was from 38 to 59 years old, that of community II was from 35 to 71 years old, that of community III was from 37 to 53 years old, that of community IV was from 50 to 72 years old, thus we supposed that the age of the study site is about from 38 to 72 years old. We supposed that the successional sere of the study site is in the early stage of ecological succession in the warm temperate climate zone. The dominant species will be changed from P. thunbergii to Q. serrata or Carpinus tschonoskii in the canopy layer, on the other hand, Eurya japonica will be dominant species in the understory layer, and E. japonica and Trachelospermum asiaticum var. intermediumwill be dominant species in the shrub layer for a while. According to the index of Shnnon's diversity(unit: $400m^2$), community I ranged from 0.8640 to 1.3986, community II was from 0.1731 to 1.1885, community III was from 0.8250 to 1.0042, and community IV was from 0.3436 to 0.6986.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.341-352
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• 2009

This study was carried out to investigated community structure of macrobenthic assemblages around the Wolseong Nuclear Power Plant, East Sea of Korea and seasonal sampling was performed from October 2007 to July 2008. A total of 163 macrobenthic fauna were collected. The overall average macrobenthos density and biomass were 1,005 individuals $m^{-2}$ and $21.81\;gWWt\;m^{-2}$, respectively. Based on the LeBris (1988) index, there were 10 dominant species accounting for approximately 69.00% of total individuals. The major dominant species were the polychaetes Spiophanes bombyx (349 inds. $m^{-2}$), Mediomastus californiensis (82 inds. $m^{-2}$), Sigambra tentaculata (55 inds. $m^{-2}$), Magelona japonica (50 inds. $m^{-2}$), Scoletoma longifolia (33 inds. $m^{-2}$) and the Unidentified amphipod (Amphipoda spp., 72 inds. $m^{-2}$). The conventional multi-variate statistics (cluster analysis and non-metric multi-dimensional scaling) applied to assess spatial variation in macrobenthic assemblages. Cluster analysis and nMDS ordination analysis based on the Bray-Curtis similarity identified 2 major station groups. The major group 1 was associated with sand dominated stations and was characterized by high abundance of the bivalves Mactra chinensis, Siliqua pulchella and the polychaete Protodorvillea egena. On the other hand, major group 2 was connected with mud dominated stations and was numerically dominated by the polychaetes M. californiensis, M. japonica, Sternaspis scutata, S. longifolia and the bivalves Thyasira tokunagai and Theora fragilis. However, macrobenthic community structure were no significant differences between the environmental variables (sediment type and depth) and heated discharge.

• Korean Journal of Biological Psychiatry
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• v.3 no.2
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• pp.277-287
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• 1996

Objective : It has been proposed that cognition and related aspects of mental functioning are decreased in depression as well as in alcoholism. The objective of the study was to compare behavioral side effects of paroxetine and amitriptyline in depressed patients accompanied by alcoholism. The focused comparisons were drug effects concerning psychomotor performance, cognitive function, sleep and daytime sleepiness during the first 2 weeks of treatment. Methods : After an alcohol detoxification period(3 weeks) and a washout period(1 week), a total of 20 male inpatients with alcohol use disorder (DSM-IV), who also had a major depressive episode(DSM-IV), were treated double-blind with paroxetine 20mg/day(n=10) or amitriptyline 25mg/day(n=10) for 2 weeks. All patients were required to have a scare of at least 18 respectively on bath the Hamilton Rating Scale far Depression(HAM-D) and Beck Depression Inventory(BDI) at pre-drug baseline. Patients randomized to paroxetine received active medication in the morning and placebo in the evening whereas those randomized to amitriptyline received active medication in the evening and placebo in the morning. All patients performed the various tasks in a test battery at baseline and at days 3, 7 and 14. The test battery included : critical flicker fusion threshold for sensory information processing capacity : choice reaction time for gross psychomotor performance : tracking accuracy and latency of response to peripheral stimulus as a measure of line sensorimotor co-ordination and divided attention : digit symbol substitution as a measure of sustained attention and concentration. To rate perceived sleep and daytime sleepiness, 10cm line Visual analogue scales were employed at baseline and at days 3, 7 and 14. The subjective rating scales were adapted far this study from Leeds sleep Evaluation Questionnaire and Epworth Sleepiness Scale. In addition a comprehensive side effect assessment, using the UKU side effect rating scale, was carried out at baseline and at days 7 and 14. The efficacy of treatment was evaluated using HAM-D, BDI and clinical global impression far severity and improvement at days 7 and 14. Results : The pattern of results indicated thai paroxetine improved performance an mast of the lest variables and also improved sleep with no effect on daytime sleepiness aver the study period. In contrast, amitriptyline produced disruption of performance on same tests and improved sleep with increased daytime sleepiness in particular at day 3. On the UKU side effect rating scale, mare side effects were registered an amitriptyline. The therapeutic efficacy was observed in favor of paroxetine early in day 7. Conclusion : These results demonstrated thai paroxetine in much better than amitriptyline for the treatment of depressed patients accompained by alcoholism at least in terms of behavioral safety and tolerability, furthermore the results may assist in explaining the therapeutic outcome of paroxetine. For example, and earlier onset of antidepressant action of paroxetine may be caused by early improved cognitive function or by contributing to good compliance with treatment.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.2
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• pp.97-105
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• 2011

This study investigated the community structure and spatio-temporal variation of macrobenthic assemblages around Gijang Province, East Sea of Korea. Macrobenthos collected seasonally using a modified van Veen grab sampler from March to November 2006. A total of 157 macrobenthic fauna were collected. The overall average macrobenthos density were $552 \;ind/m^2$. The species number of macrobenthos was in the range from 62 in winter and spring to 122 in autumn. On the other hand, abundance fluctuated between 6,540 (in spring) and 17,920 (in autumn) inds./$18m^2$. Cluster analysis and non-metric multi-dimensional scaling (nMDS) were applied to assess the spatio-temporal fluctuation in the macrobenthic assemblages. Cluster analysis and nMDS ordination analysis based on the Bray-Curtis similarity identified 3 station groups. The group 1 (station 8~10, 12, 13, 17 and 18) was characterized by high abundance of the polychaete Lumbrineris longifolia, the bivalve Ennucula tenuis and the Amphipoda spp., with mean phi range from $6.2{\Phi}$ to $7.1{\Phi}$ (above 50m water depth). The group 2 (station 5~7, 11, 14~16) was numerically dominated by the po1ychaete Ampharete arctica and the bivalve Theorafragilis (mean phi: $6.0{\sim}7.0{\Phi}$; within 40 m water depth). Finally group 3 (station 1~4) was characterized by high density of the polychaetes Magelona japonica and Sternaspis scutata, with mean phi range from $3.5{\Phi}$ to $6.9{\Phi}$ (below 30 m water depth). In conclusion, the Macrobenthic community structure showed a distinct spatial and temporal trend, which seemed to be related to the water depth and sediment composition.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.29-44
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• 2005

The purpose of this study is to reveal the effects of two different kicks, the drop kick and the punt kick, into the kicking motion, through the kinetic comparative analysis of the kicking motion, which is conducted when one kicks a soccer goal. To grasp kinetic changing factors, which is performed by individual's each body segment, I connected kicking motions, which were analyzed by a two dimension co-ordination, into the personal computer to concrete the digits of it and smoothed by 10Hz. Using the smoothed data, I found a needed kinematical data by inputting an analytical program into the computer. The result of comparative analysis of two kicking motions can be summarized as below. 1. There was not a big difference between the time of the loading phase and the time of the swing phase, which can affect the exact impact and the angle of balls aviation direction. 2. The two kicks were not affected the timing and the velocity of the kicking leg's segment. 3. In the goal kick motion, the maximum velocity timing of the kicking leg's lower segment showed the following orders: the thigh(-0.06sec), the lower leg(-0.05sec), the foot(-0.018sec) in the drop kick, and the thigh(-0.06sec), the lower leg(-0.05sec), the foot(-0.015sec) in the punt kick. It showed that whipping motion increases the velocity of the foot at the time of impact. 4. At the time of impact, there was not a significant difference in the supporting leg's knee and ankle. When one does the punt kick, the subject spreads out his hip joint more at the time of impact. 5. When the impact performed, kicking leg's every segment was similar. Because the height of the ball is higher in the punt kick than in the drop kick, the subject has to stretch the knees more when he kicks a ball, so there is a significant affect on the angle and the distance of the ball's flying. 6. When one performs the drop kick, the stride is 0.02m shorter than the punt kick, and the ratio of height of the drop kick is 0.05 smaller than the punt kick. This difference greatly affects the center of the ball, the supporting leg's location, and the location of the center of gravity with the center of the ball at the time of impact. 7. Right before the moment of the impact, the center of gravity was located from the center of the ball, the height of the drop kick was 0.67m ratio of height was 0.37, and the height of the punt kick was 0.65m ratio of height was 0.36. The drop kick was located more to the back 0.21m ratio of height was 0.12, the punt kick was located more to the back 0.28m ratio of height was 0.16. 8. There was not a significant difference in the absolute angle of incidence and the maximum distance, but the absolute velocity of incidence showed a significant difference. This difference is caused from that whether players have the time to perform of not; the drop kick is used when the players have time to perform, and punt kick is used when the players launch a shifting attack. 9. The surface reaction force of the supporting leg had some relation with the approaching angle. Vertical reaction force (Fz) showed some differences in the two movements(p<0.05). The maximum force of the right and left surface reaction force (Fx) didn't have much differences (p<0.05), but it showed the tendency that the maximum force occurs before the peak force of the front and back surface (Fy) occurs.