• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.4
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• pp.314-322
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• 2012

In order to elucidate temporal variations of temperature, salinity, pH, dissolved oxygen (DO), suspended particulate matter (SPM), dissolved inorganic nutrients, and chlorophyll a, we performed 25-hour continuous monitoring in the Seomjin River Estuary in March (dry season) and July (rainy season) 2006. We also investigated spatial variations of marine environmental parameters across a saline gradient. In the Seomjin River Estuary, continuous monitoring results revealed that salinity variations were mainly affected by tidal cycle in the dry season and by river discharge in the rainy season. In the dry season, the spatio-temporal distribution of dissolved inorganic nutrient (nitrate, nitrite, and silicate) concentrations showed a good correlation with tidal cycle. While nutrient concentrations in rainy season showed not much variance in time. There were 6 and 4 times higher dissolved inorganic nitrogen and phosphorus concentrations in the rainy season than those in the dry season, respectively. Silicate concentration was 43 times higher in the rainy season than that in the dry season. Chlorophyll a concentration was higher in the dry season than that in the rainy season showing high nutrient concentrations. The results of this study, spatio-temporal variations of marine environmental factors are determined by both tidal cycle and river discharge. It seems that chlorophyll a concentration is related to the river discharge than dissolved inorganic nutrient distribution.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.368-383
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• 2014

Climate change is expected to affect population density, phenology, distribution, morphological traits, reproduction and genetics of insects, and even in the extinction of insects. To develop novel research subjects for predicting climate change effect, basic information about biological and ecological data on insect species should be compiled and reviewed. For this reason, this study was conducted to collect the biological information on insect pests that are essential for predicting potential damage caused by insect pests in future environment. In addition, we compared domestic and foreign research trends regarding climate change effect and suggested future research subjects. Domestic researchers were rather narrow in the subject, and were mostly conducted based on short-term monitoring data to determine relationship between insects and environmental variables. On the other hand, foreign researches studied on various subjects to analyze the effect of climate change, such as changes in distribution of insect using long-term monitoring data or their prediction using population parameters and models, and monitoring of the change of the insect community structure. To determine change of the phenology, distribution, overwintering characteristics, and genetic structures of insects under climate change through development of monitoring technique, in conclusion, further researches are needed. Also, development of population models for major or potential pests is important for prediction of climate change effects.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.72-81
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• 2007

The purpose of this study was to develop a multi-metric Lentic Ecosystem Health Assessment (LEHA) model and apply model to dataset sampled from Daechung Reservoir in September 2005. The metrics were composed of 11 parameters such as physical, chemical and biological variables. The metric attributes of $M_1{\sim}M_8$ followed after the model of biological integrity using fish assemblages that previously adapted in lotic ecosystems, while the metrics of $M_9{\sim}M_{11}$ were added on the basis of literature. The metric of $M_9$ reflected habitat conditions in the littoral zone and the metric of $M_{10}$ reflected chemical conditions of the reservoir. For the application of regression analysis of long-transformed conductivity [$Log_{10}$(Cond)] against $COD_{Mn}$, based on 150 sampling sites at Korean reservoirs, showed that the variation of conductivity was explained 77.4% [$COD_{Mn}=4.42{\times}Log_{10}(Cond)-5.43;\;R^2=0.774$, p<0.01, n=150] by the variation of $COD_{Mn}$. The metric of $M_{11}$ was based on Tropic State Index (TSI), based on chlorophyll-${\alpha}$ concentrations (Chl-${\alpha}$). Analysis of TSI $(Chl-{\alpha})$ showed that above 50 was estimated "1", $40{\sim}50$ was estimated "3" and below 40% was estimated '5'. Overall, velues of LEHA in the reservoir averaged 30.5, indicating a "fair${\sim}$poor condition", which is judged by the criteria of U.S. EPA (1993). More studies such as metric numbers and attributes should be done for the application of the model.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.3
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• pp.210-221
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• 2000

The population habitat and density of Korean scallops, Chlamys farreri, were investigated to estimate population ecological characteristics from samples randomly collected around Wando from November, 1998 to October, 1999. Age and growth of the Korean scallops were determined from their ring radii. Maturation and spawning were studied using data of ovary maturity stage, gonadosomatic index, and fecundity. Seawater temperature and specific gravity ranged from 7.6 to $25.9^{\circ}C$ and from 1.0188 to 1.0260, respectively. Also dissolved oxygen and pH ranged from 6.48 to 9.50 ppm and from 8.17 to 8.80. Rocky and gravel bottom had a maximum habitat density of $$28.83 inds/100m^2$$ , which accounted for 82.4 % of the overall habitat area. The relationship between shell length (SL, mm) and shell height (SH, mm) of the Korean scallops was fitted : SH=1.021 SL+2.211 $(R^2=0.989)$. The shell length-total weight (TW, g) relationship was $TW=0.0003; SL^{2.837};(R^2=0.980)$. Then von Bertalanffy growth parameters were estimated from a nonlinear regression method, and the values were as follows : $SH_{\infty}=117.4 mm$K=0.61/year,; and; t_0=-0.017 year., The 50 % maturity at age was 0.21 year with the shell height of 18.3 mm, and spawning occurred twice a year, that is, June/July and October. The relationship between fecundity (Fc) and shell length was$Fc=697.03 SL^{2.683}(R^2=0.984)$, and the fecundity-gonad weight (GW, g) relationship was Fc=10,076,090 GW+15,608,781 $(R^2=0.990)$.

• Journal of Environmental Science International
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• v.23 no.8
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• pp.1447-1453
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• 2014

The differentiation of sex is important for species preservation. However, Fairy Pitta is sexually monomorphic and sex of an individual is indistinguishable with its external characteristics. We determined the sex of Fairy Pitta through DNA analysis and investigated the causes and time of injury and mortality and the size based on sex. We collected 21 samples at Jeju Island, Korean Peninsula from 2004 to 2013 and extracted DNA from them and amplified chromo helicase DNA-binding gene from Z and W chromosomes through Polymerase Chain Reaction (PCR). We confirmed their sex with the banding pattern through Agarose gel electrophoresis, i.e. male (ZZ): one banded and female (ZW) two banded. We distinguished the sex of 17 of 21 samples resulting in 9 males and 8 females. Most casualties were recorded in adult of both sexes. Causes of injury and mortality proved that female casualties occurred from window strikes, dehydration, car accident, predation by natural enemies, and male occurred from window strikes, car accident and dehydration. The time of injury and mortality in adults differ by sex. There was no difference between sexes in any of the six size parameters. As the time of injury and mortality differ by sex, the survey on the role and ecological nature by sex in breeding season must be carried out in the future. External measurements may not be reliable for sexing of Fairy Pitta and other traits such as vocal or characteristics are required to identify the sex of individuals in the field.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1340-1346
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• 2005

A water quality modeling study was performed for Chunggye stream during combined sewer overflow(CSO) period, utilizing the diagnostic system for water management in small watershed, CREEK-1(Cyber River for Environment and Economy in Korea). This system integrated geogaphic information system, data base, landscape ecological model(FRAGSTATS), watershed model(SWMM), water quality model (WASP5), and computer graphic. In this study, the watershed model and water quality model were extensively utilized so as to simulate water qualities and flow in Chunggye stream during wet periods. The Chunggye stream watershed was divided into 18 sub-basins in the watershed model and the stream reach into 11 segments in the water quality model. The watershed model was validated against field measurements of BOD, TN, TP, and flow at the downstream location, where the model results showed a reasonable agreement with the field measurements at all parameters. From this study, it was shown that the stream water quality would change along with elapsed time from rainfall start as well as rainfall intensity. The model results indicated that the water quality would significantly upgrade due to the first flush and high sewage ratio of CSO at the beginning of rainfall event, but become degraded along with the runoff increase due to dilution effect.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.163-163
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• 2003

The study area, Kwangneung Experiment Forest (KEF) is located on the west-central portion of Korean peninsula and belongs to a cool-temperate broadleaved forest zone. At the old-growth deciduous forest near Soribong-peak (533.1m) in KEF, we have established a permanent plot and a flux tower, and the site was registered as a KLTER site and also a KoFlux site. In this study, we aimed to present basic ecological characteristics and synthetic data of carbon budgets and flows, and some monitoring data which are essential for providing important parameters and validation data for the forest dynamics models or biogeochemical dynamics models to predict or interpolate spatially the changes in forest ecosystem structure and function. We made a stemmap of trees in 1 ha plot and analyzed forest stand structure and physical and chemical soil characteristics, and estimated carbon budgets by forest components (tree biomass, soils, litter and so on). Dominant tree species were Quercus serrata and Carpinus laxiflora, and accompanied by Q. aliena, Carpinus cordata, and so on. As a result of a field survey of the plot, density of the trees larger than 2cm in DBH was 1,473 trees per ha, total biomass 261.2 tons/ha, and basal area 28.0 m2/ha. Parent rock type is granite gneiss. Soil type is brown forest soil (alfisols in USDA system), and the depth is from 38 to 66cm. Soil texture is loam or sandy loam, and its pH was from 4.2 to 5.0 in the surface layer, and from 4.8 to 5.2 in the subsurface layer. Seasonal changes in LAI were measured by hemispherical photography at the l.2m height, and the maximum was 3.65. And the spatial distributions of volumetric soil moisture contents and LAIs of the plot were measured. Litterfall was collected in circular littertraps (collecting area： 0.25m2) and mass loss rates and nutrient release patterns in decomposing litter were estimated using the litterbag technique employing 30cm30cm nylon bags with l.5mm mesh size. Total annual litterfall was 5,627 kg/ha/year and leaf litter accounted for 61% of the litterfall. The leaf litter quantity was highest in Quercus serrata, followed by Carpinus laxiflora and C. cordata, etc. Mass loss from decomposing leaf litter was more rapid in C. laxiflora and C. cordata than in Q. serrata litter. About 77% of C. laxiflora and 84% of C. cordata litter disappeared, while about 48% in Q. serrata litter lost over two years. The carbon pool in living tree biomass including below ground biomass was 136 tons C/ha, and 5.6 tons C/ha is stored in the litter layer, and about 92.0 tons C/ha in the soil to the 30cm in depth. Totally more than about 233.6 tons C/ha was stored in DK site. And then we have drawn a schematic diagram of carbon budgets and flows in each compartment of the KEF site.

• 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$^2$.

• Management & Information Systems Review
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• v.35 no.3
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• pp.131-153
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• 2016

This research suggests a structural model of green purchase behavior, focusing on the moderating effect of affordability. Affordability means buying power or ability to buy products. Based on the literature review, a research model of behavior of buying green products was proposed and tested empirically using the field study. To examine the proposed research model, the reliability and validity verifications on measurement items were carried out and then the structural equation model analysis was applied to test the model. Lastly, to test the moderating effect of affordability, a two-group model(using Amos program) was used subsequently so that it could be determined whether or not there was any significant difference in structural parameters between the high affordability group and the low affordability group. The empirical results are as follow: Firstly, green purchase attitude is influenced by ecological concern and collectivism, then green purchase attitude has an impact on green purchase intention, and in turn, green purchase intention affects green purchase behavior. Secondly, affordability significantly moderates the relationship between green purchase intention and green purchase behavior. These results are consistent with the past researches and based on them, some managerial implications are given.

• Journal of Korean Society of Forest Science
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• v.80 no.4
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• pp.360-368
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• 1991

Utilizing chi-square test statistics, inter-species association and covariation were analyzed for the 37 woody plant species in a deciduous forest dominated by Quercus mongolica and Q. variabilis. within 50 temporarily established $20m{\times}20m$ square quadrats, the association for each pair of species was presented based on the presence-absence parameters. Acer palmatum had significant positive association with Acer mono and Kalopanax pictus, but negative association with Pinus densiflora. Other positively associated species pairs were Prunus sargentii-Macckia amurensis, Quercus serrata-Kalopanax pictus, Symplocos chinensis var. pilosa-Euonymus oxyphyllus, and Ulmus davidiana var. japonica-Lindera obtusiloba. The covariation far each pair of species was evaluated based on the quantitative measures, density and basal area. Overall results showed that the association and covariation values among species generally agreed with each other. Because covariation was calculated by density and basal area of the tallied species in the sample plots, the number of species pairs of covariation tended to be greater than those of association. Especially, Pinus densiflora, considered to be pioneer species in the successional stage, had negative covariation with most of climax species. These ecological information could be applied to silvicultural practices, such as ecosystem classification, establishment of mixed hardwood forest, and tending operations for marking crop trees and desirable species.