• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.393-401
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• 2013

The objectives of this study were to analyze structures of fish community and the ecological health using a multi-metric fish model, the Index of Biological Integrity (IBI) in the Backje Weir of Geum River during two periods namely before-the-fishkill ($B_f$) and after-the-fishkill ($A_f$). The total number of fish species observed were 32 and among them 10 species (35%) were Korean endemic species. The exotic species observed were 3 which decreased by 0.4% after-the-fishkill ($A_f$). The dominant species were Opsariichthys uncirostris amurensis (13%) at the Bf period and Squalidus japonicus coreanus (17%) at the Af period in the Backje Weir. At after the fishkill ($A_{f-I}$) total biomass was about 10 times lower than the biomass before-the-fishkill ($B_f$). The biomass of Carassius auratus decreased 98% after-the-fishkill and as time passed by the biomass recovered to nearly 100%. Similar decrease in the biomass occurred in the population of Opsariichthys uncirostris amurensis, while Rhinogobius brunneus population increased. According to the structure analysis of fish community, species richness index, evenness index and species diversity index were high but after-the fishkill, the values of indices decreased. Tolerant species (64%) dominated the fish community, and the sensitive species (2%) were rare, indicating the degradation of the ecosystem. According to analysis of the multi-metric model (IBI), the mean model value of the fish community in Backje Weir was estimated as 17.5 indicating a "fair condition".

• Korean Journal of Heritage: History & Science
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• v.44 no.2
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• pp.4-25
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• 2011

This study was performed in 2010 to examine the flora and vegetation structure and chemical characteristics of soil in the growing community of Abeliophyllum distichum, located in the Byeonsanbando National Park. This Abeliophyllum distichum community has more individual numbers in Cheongrim-ni and Jungkye-ri, Byeonsan-myeon, and Buan-gun area, which is designated as a Natural Monument (No. 370), and also where the habitat conditions for Abeliophyllum distichum is more favorable. The authors recorded 100 taxa with 45 families, 82 genus, 93 species, 4 varieties, and 3 forms. Among them, species such as Abeliophyllum distichum (critically endangered), Asarum maculatum (near threatened) and Chionanthus retusa (near threatened), which are categorized as rare plants, were recorded. According to the list of Korean endemic plants, 4 taxa, particularly Philadelphus schrenckii, Abeliophyllum distichum, Weigela subsessilis, and Lonicera subsessili, were recorded. The community of Abeliophyllum distichum is located in the northwest slope of Baekcheon watershed and the community is comprised of healthy soil. The community structure was classified into three: the Castanea crenata community, Zelkova serrata community, and Quercus serrata community. The Castanea crenata community is composed of the Cornus walteri, Platycarya strobilacea, Zelkova serrata, Rhamnella frangulioides, arranged in terms of importance percentage. The Zelkova serrata community is composed of Celtis sinensis, Quercus aliena, Styrax japonica, and Acer pseudo-sieboldianum, also according to importance percentage. As for the Quercus serrata community, it is composed of Quercus variabilis, Castanea crenata, and Prunus sargentii, also arranged in terms of importance percentage. The importance percentage of Abeliophyllum distichum is 6.6% in the Castanea crenata community, 5.6% in the Zelkova serrata community and 5.1% in the Quercus serrata community. Moreover, in order of chemical characteristics of soil pH, electrical conductivity, available phosphoric, organic matter, and exchangeable cation (K, Ca, Mg) are analyzed. The No. 3 site was relatively higher than other districts of the same chemical characteristics of soil.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.409-422
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• 2022

Two dominant thrips in hot pepper (Capsicum annuum) cultivating in greenhouses are Frankliniella occidentalis and F. intonsa in Korea. This study investigated their overwintering physiology. These two thrips were freeze-susceptible and suppressed the body freezing temperature by lowering supercooling point (SCP) down to -15~-27℃. However, these SCPs varied among species and developmental stages. SCPs of F. occidentalis were -25.7±0.5℃ for adults, -17.2±0.3℃ for pupae, and -15.0±0.4℃ for larvae. SCPs of F. intonsa were -24.0±1.0℃ for adults, -27.0±0.5℃ for pupae, -17.2±0.8℃ for larvae. Cold injuries of both species occurred at low temperature treatments above SCPs. Thrips mortality increased as the treatment temperature decreased and its exposure period increased. F. occidentalis exhibited higher cold tolerance than F. intonsa. In both species, adults were more cold-tolerant than larvae. Two thrips species exhibited a rapid cold hardening because a pre-exposure to 0℃ for 2 h significantly enhanced the cold tolerance to a lethal cold temperature treatment at -10℃ for 2 h. In addition, a sequential exposure of the thrips to decreasing temperatures made them to be acclimated to low temperatures. To investigate the overwintering sites of the two species, winter monitoring of the thrips was performed at the greenhouses. During winter season (November~February), adults of the two species were not captured in outside of the greenhouses. However, F. occidentalis adults were captured to the traps and observed in weeds within the greenhouses. F. occidentalis adults were also emerged from soil samples obtained from the greenhouses during the winter season. F. intonsa adults did not come out from the soil samples at November and December, but emerged from the soil samples obtained after January. To determine the adult emergence due to diapause development, two thrips species were reared under different photoperiods. Adult development occurred in all photoperiod treatments in F. occidentalis, but did not in F. intonsa especially under short periods. Tomato spotted wilt virus, which is transmitted by these two species, was detected in the weeds infested by the thrips during the winter season. These results suggest that F. occidentalis develops on weeds in the greenhouses while F. intonsa undergoes a diapause in the soil during winter.

• Proceedings of the KSEEG Conference
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• 2001.05b
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• pp.42-63
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• 2001

The detail survey on the Songsanri tomb site including the Muryong royal tomb was carried out during the period from May 1 , 1996 to April 30, 1997. A quantitative analysis was tried to find changes of tomb itself since the excavation. Main subjects of the survey are to find out the cause of infiltration of rain water and groundwater into the tomb and the tomb site, monitoring of the movement of tomb structure and safety, removal method of the algae inside the tomb, and air controlling system to solve high humidity condition and dew inside the tomb. For these purposes, detail survery inside and outside the tombs using a electronic distance meter and small airplane, monitoring of temperature and humidity, geophysical exploration including electrical resistivity, geomagnetic, gravity and georadar methods, drilling, measurement of physical and chemical properties of drill core and measurement of groundwater permeability were conducted. We found that the center of the subsurface tomb and the center of soil mound on ground are different 4.5 meter and 5 meter for the 5th tomb and 7th tomb, respectively. The fact has caused unequal stress on the tomb structure. In the 7th tomb (the Muryong royal tomb), 435 bricks were broken out of 6025 bricks in 1972, but 1072 bricks are broken in 1996. The break rate has been increased about 250% for just 24 years. The break rate increased about 290% in the 6th tomb. The situation in 1996 is the result for just 24 years while the situation in 1972 was the result for about 1450 years. Status of breaking of bircks represents that a severe problem is undergoing. The eastern wall of the Muryong royal tomb is moving toward inside the tomb with the rate of 2.95 mm/myr in rainy season and 1.52 mm/myr in dry season. The frontal wall shows biggest movement in the 7th tomb having a rate of 2.05 mm/myr toward the passage way. The 6th tomb shows biggest movement among the three tombs having the rate of 7.44mm/myr and 3.61mm/myr toward east for the high break rate of bricks in the 6th tomb. Georadar section of the shallow soil layer represents several faults in the top soil layer of the 5th tomb and 7th tomb. Raninwater flew through faults tnto the tomb and nearby ground and high water content in nearby ground resulted in low resistance and high humidity inside tombs. High humidity inside tomb made a good condition for algae living with high temperature and moderate light source. The 6th tomb is most severe situation and the 7th tomb is the second in terms of algae living. Artificial change of the tomb environment since the excavation, infiltration of rain water and groundwater into the tombsite and bad drainage system had resulted in dangerous status for the tomb structure. Main cause for many problems including breaking of bricks, movement of tomb walls and algae living is infiltration of rainwater and groundwater into the tomb site. Therefore, protection of the tomb site from high water content should be carried out at first. Waterproofing method includes a cover system over the tomvsith using geotextile, clay layer and geomembrane and a deep trench which is 2 meter down to the base of the 5th tomb at the north of the tomv site. Decrease and balancing of soil weight above the tomb are also needed for the sfety of tomb structures. For the algae living inside tombs, we recommend to spray K101 which developed in this study on the surface of wall and then, exposure to ultraviolet light sources for 24 hours. Air controlling system should be changed to a constant temperature and humidity system for the 6th tomb and the 7th tomb. It seems to much better to place the system at frontal room and to ciculate cold air inside tombs to solve dew problem. Above mentioned preservation methods are suggested to give least changes to tomb site and to solve the most fundmental problems. Repairing should be planned in order and some special cares are needed for the safety of tombs in reparing work. Finally, a monitoring system measuring tilting of tomb walls, water content, groundwater level, temperature and humidity is required to monitor and to evaluate the repairing work.