• Korean Journal of Ecology and Environment
• /
• v.41 no.2
• /
• pp.155-165
• /
• 2008

The purpose of this study was to evaluate the ecosystem of Yeongsan Lake using physical, chemical, and biological indicators. We evaluated the integrative ecosystem health using Lentie Ecosystem Health Assessment (LEHA) model, Qualitative Health Evaluation Index (QHEI) model, and chemical water quality. The models of LEHA and QHEI were modified as 10 and 7 metries attributes, respectively. Also, we analyzed bioaccumulation of total mercury on various fish tissues by method of U.S. EPA 7473 using Direct Mercury Analyzer (Model DMA-80). Model values of LEHA model averaged 19 (range: $14{\sim}26$, n=15), which indicated a "poor" condition, and had slightly spatial variations. Values of the QHEI in the all sites averaged 72, which were judged as a "fair" to "good" condition. The QHEI values varied from 48 (fair condition) to 99 (good condition) and showed large longitudinal gradients between the upper and lower reach. Conductivity and salinity were increased from the up-lake to downlake reach. Analysis of total mercury in fish tissues showed that levels of total Hg ranged between 0.002 and $0.087\;mg\;L^{-1}$ depending on the types of tissues. Overall, the ecosystem health in the Yeongsan Lake was judged as a "poor" and the effects of bioaccumulation on the fish tissues were minor. Therefore, it is necessary to keep an efficient management for the lake environment to maintain their ecological health.

• Korean Journal of Ecology and Environment
• /
• v.50 no.3
• /
• pp.314-324
• /
• 2017

In order to consider application and evaluation of value and class of domestic wetland, we investigated 146 wetlands located Gyeongsangnam-do using Rapid Assessment Method (RAM). We utilized Self-Organizing-Map (SOM) to analysis relationship between evaluation index and land coverage ratio surrounding wetland. Among total 8 evaluation index, 'Fish and herptile habitat' and 'Aesthetic value' were higher, most of the wetlands evaluated as 2, 3 grade. Result of SOM analysis, 'vegetation diversity and wild animals habitat' is negatively related to the 'Fish and herptile habitat', because fishs were not prefer habitat excessively occupied by plant. However, high vegetation diversity can be support high score of 'Aesthetic' in wetland. Also, 'Erosion control' and 'Flood storage and control' were closely related, wetlands with high score of 'Erosion control' have high score of 'Flood storage and control'. When applied RAM in domestic wetland, six out of 6 evaluation index induced biased results, the index of RAM need a little change as some new or modify evaluation index. Therefore, we consider to need adjustable, subdivide, and actualization of some evaluation index for application of RAM in domestic wetlands. Consequently, wetland assessment and class using RAM can be utilized as important indicate for conservation and management of wetland, and contributed greatly to maintain biodiversity include to endangered species by preserving remaining wetland.

• Economic and Environmental Geology
• /
• v.18 no.3
• /
• pp.277-288
• /
• 1985

Mineral composition and grain size analyses of the sandstone from the Early Jurassic Daedong Group distributed in Mungyeong, Daecheon, Kimpo and Yeoncheon areas were made for the study of provenances and depositional environments. The most of the analyses are obtained from Mungyeong area, with some preliminarly works from Daecheon, Kimpo and Yeoncheon areas. All sandstones from the study area are characterized by high content of quartz ranging from 59.8 to 87.2 percent of total constituents. Many of quartz which has rounded dust ring seems to come from aeolian sediments. Content of feldspar is very low except Daecheon area where it ranges from 1.8 to 10.0 percent. Sandstones from Mungyeong, Kimpo and Yeoncheon areas are classified as quartz and quartzose arenite/wacke, while those from Daecheon area are classified as quartzose and lithic arenite/wacke. According to the character of the sandstones, provenance could be quartzose sandstone and quartzite. Results of grain size analysis of C-M and sorting versus skewness suggest that depositional environment seems to be fluvial, while log-probability curve pattern lacustrine environment. It is hard to derive a definite conclusion of sedimentary environment by the grain size analysis.

• Ecology and Resilient Infrastructure
• /
• v.6 no.4
• /
• pp.243-249
• /
• 2019

The purpose of this study is to analyze the reflectance of bed materials according to changes in the water level using a drone-based hyperspectral sensor. For this purpose, we took hyperspectral images of bed materials such as soil, gravel, cobble, reed, and vegetation to compare and analyze the spectral data of each material. To adjust the water level, we constructed an experimental channel to control the discharge and installed the bed materials within the channel. In this study, we configured 3 cases according to the water level (0.0 m, 0.3 m, 0.6 m). After the imaging process, we used the mean value of 10 points for each bed material as analytical data. According to the analysis, each material showed a similar reflectance by wavelength and the intrinsic reflectance characteristics of each material were shown in the visible and near-infrared region. Also, the deeper the water level, the lower the peak reflectance in the visible and near-infrared region, and the rate of decrease differed depending on the bed material. We expect the intrinsic properties of these bed materials to be used as basic research data to evaluate river environments in the future.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.15 no.2
• /
• pp.103-115
• /
• 2012

To investigate the attributes of seed germination of the plants for greening of river bank slope, low-temperature treatment, chemical treatment, plant hormones treatment, and stratification were conducted using the seeds of 6 herbs growing naturally around river banks, such as Setaria glauca and faberii, Imperata cylindrica var. koenigii, Miscanthus sinensis, Pennisetum alopecuroides, Lespedeza cuneata and the seeds of 3 shrubs, such as Lespedeza bicolor., Rosa multiflora, Spiraea prunifolia for. simpliciflora. The findings are as follows. In case of herbs, Setaria glauca and faberii. have stone seeds. In the treatment with $H_2SO_4$, they were germinated through dormancy breaking, even though there were some differences depending on immersion time, and the germination rate of Setaria faberii was a bit higher than that of Setaria glauca. The germination rate of Imperata cylindrica var. koenigii was low in the treatment with $GA_3$, NAA, and the plant hormone, but the seed germination rate has improved and the germination rate of Miscanthus sinensis and Pennisetum alopecuroides showed the improved seed germination rate in low temperature treatment. In case of Lespedeza cuneata and bicolor, the leguminous plants, the treatment with $H_2SO_4$ was most effective for the improvement of seed germination and the decrease in germination time. Only Spiraea prunifolia for. simpliciflora, the rose among 3 woody plants showed the seed germination rate above 50% without any additional treatment. Thus, it was thought to be appropriate for greening. Rosa multiflora showed the attribute of germination in a dark condition at low temperature through stratification, despite its low germination rate. Based on the results as above, with respect to the greening using directly collected seeds, Miscanthus sinensis, Pennisetum alopecuroides, and Spiraea prunifolia for. simpliciflora are suitable for greening, because they do not need any additional treatment, and Lespedeza cuneata and bicolor are also suitable for greening because it is possible to improve the germination rate and reduce the germination time through the treatment on the seeds before sowing.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.12 no.2
• /
• pp.75-83
• /
• 2009

In order to understand the impacts of the construction of artificial sea dikes on carbon cycle in Samangeum area being a closed environment after April, 2006, we had measured suspended particulate matters, particulate and dissolved organic carbon in the surface water of inner Saemangeum dike from 2003 to 2006. The significant inputs of suspended particulate matter and organic carbon were mainly occurred during the wet season which suggests that most organic matter loading is concentrated within a short period of time inside the dike. The concentrations of particulate matter and organic carbon have gradually increasing every year inside of dike from the Mangyeong river estuary to Saemangeum dike, which has been closed since 2003 after the construction of the 4th dike. The particulate organic carbon increased due to the phytoplankton blooms by eutrophication. If the large portion of particulate organic matter produced in the surface water sink to the bottom sediment, this will cause the anoxic condition in this closed environment.

• Korean Journal of Ecology and Environment
• /
• v.39 no.2 s.116
• /
• pp.178-186
• /
• 2006

Community structures of fish in six small eutrophied lakes, located in Gyeonggi province, Korea were investigated from September 2003 to August 2004. Total number of fish species was 33 species of 13 families in which five Korean endemic species such as Rhodeus uyekii, Squalidus gracilis majimae, Abbottina springeri, Iksookimia koreensis, and Odontobutis interrupta were found. Dominant species in the lakes was Hemiculter leucisculus. Both Zacco platypus and Pseudorasbora parva were numberous as subdominant species. In particlilar, Micropercops swinhonis known as partly distributed in the Jeonlabukdo was first recorded in Lake Wangsong and Heungbu which are located in the Gyeonggi province. In lake Myukwoo, Wangsong, and Heungbu, the proportion of Pelagic and omnivorous fish were high, reflecting that fish habitat is poor. A CPUE based fish production was the lowest in Lake Geumgwang of which lake is relatively favorable, whereas it was higher in eutriphied lakes suchs as Dukwoo, Myukwoo and Heungbu lakes.

• Korean Journal of Ecology and Environment
• /
• v.48 no.1
• /
• pp.32-37
• /
• 2015

Naturalized plants are invaded through various routes and distributed throughout the nation. They are also invaded in the sand dune ecosystem and poses a threat ecological niche of indigenous sand dune plants. We studied the effects of salt stress on the plant growth to suggest the management plans of naturalized plants in the sand dune ecosystem. As a result of germination experiment according to the salt gradient, germination rate decreased as the higher concentration and tolerance range was up to 160 mM. As a result of seedling experiment according to salt gradient, mortality rate was up to 90% from 0 mM to 200 mM and 100% over 300 mM. The day of first death with different concentration was 18.5 days in 100 mM and 6 days in 800 mM since the experiment has started. In addition, the day of last death with different concentration was 29.5 days in 100 mM and 6 days in 800 mM. Therefore, two stages of management plans would be effective. The first one is to suppress the germination by salt spray over 170 mM before germination. The other one is to wither seedlings in a short period by salt spray over 600 mM.

• Korean Journal of Ecology and Environment
• /
• v.44 no.2
• /
• pp.195-202
• /
• 2011

This study analyzed and modeled the relationships between the probabilities of two exotic species occurrence (i.e. largemouth bass and blue gill) and environmental factors such as climatic and geographical variables using Generalized Additive Models (GAM), Generalized Liner Models and Classification Tree Analysis (CTA). The most moderate occurrence probability of largemouth bass was predicted using GAM with an area under the curve (ADC) of 0.88 and Kappa of 0.42, while those of blue gill was suggested by using CTA with an AUC of 0.92 and Kappa of 0.44. The most significant environmental variable in terms of changes in deviance for both species was the annual air temperature for the occurrence probability. Dams had stronger effect on the occurrence of largemouth bass than blue gill. Model development and prediction for the occurrence probability of fish species and richness are necessary to prevent further spread of exotic fishes such as largemouth bass and blue gill because they can threaten habitats of native river ecosystem through various mechanisms.

• Korean Journal of Ecology and Environment
• /
• v.44 no.2
• /
• pp.187-194
• /
• 2011

This study analyzed the A1B climate change scenario provided by National Institute of Meteorological Research (NIMR), Korea, to investigate potential climate changes in watersheds of 15 multi-purpose dams in South Korea. The A1B climate change scenario is produced by Regional Climate Model (RCM) with 27 km horizontal grid spacings using a one-way nesting technique with Global Climate Model (GCM). Relative to present climate conditions (1971~ 2000), the modeled 10-year averaged daily temperatures at the watersheds of the 15 multi-purpose dams continuously increased to year 2100, whereas precipitation changes were varied regionally (north, central, and south regions of South Korea). At two watersheds located in Gangwon-province (north region), the modeled temporal variations of precipitation rapidly increased in the 2090's after a slow decrease that had occurred since the 2050's. At seven watersheds in the central region, including Gyeongsangbuk-province to Jeollanam-province, the modeled temporal variations of precipitation increase showed 10-year periodic changes. At six watersheds in the south region, the modeled temporal variations of precipitation increased since the 2070's after a rapid decrease in the 2060's. Compared to the climate conditions of the late of 20th century (1971~2000), the number of rainy days and precipitation intensity increased (3% and 6~12%, respectively) in the late 21st century (2071~2100). The frequency of precipitation events tended to increase with precipitation intensity in all regions. The frequency of heavy precipitation events (>50 mm $d^{-1}$) increased with >100% in the north region, 60~100% in the central region, and 20~60% in the south region.