• Animal Systematics, Evolution and Diversity
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• v.36 no.3
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• pp.251-257
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• 2020

The genus Plectus Bastian, 1865 represents a group of free-living freshwater nematodes belonging to the family Plectidae Örley, 1880. However, only one species has been reported thus far from Korea. Plectus aquatilis Andrássy, 1985 and Plectus cirratus Bastian, 1865 are reported for the first time from Korea, from sediments collected from the Nakdong River. Plectus aquatilis is distinguished from other Plectus species by its three longitudinal alae in the lateral field, thin and directed cephalic setae, continuous lip region (head not set-off), and rectangular shaped tail. Plectus cirratus is distinguished from other Plectus species by its large body, two longitudinal alae in the lateral field, larger stoma, and longer tail. Morphological characters and measurements of the specimens generally agree with the original descriptions of Plectus species. Here, the morphological characters (detailed morphometrics) of two species in the genus Plectus are fully redescribed and illustrated using optical microscopy. DNA barcode sequence information from the 18S rDNA gene is also provided for molecular species identification and compared with sequences from other Plectus species available on GenBank.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.4
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• pp.69-84
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• 2020

Up to date, the majority research on the major landscape elements in organic farming has been mainly focused on the practice of seeking efficiency. The problem is that this type of study contributes to polluting the agricultural environment and damaging the ecological circulation system. As an alternative, there is a growing body of research on organic farming, but it is not widely applied that research on how to manage the landscape considering the scenic characteristics of farming villages practicing organic farming. Hence, in this paper we utilized landscape adjectives as a way to enhance the objectivity of the organic agricultural complex landscape assessment. More specifically, not only this study used a landscape image of an organic agricultural complex to identify a landscape adjective suitable for the landscape elements but also this study confirmed the suitability of landscape adjectives comparing to the opinions of experts and the public. To carry out, this study performed the experts survey which is composed of 12 major landscape elements, including rice paddies and fields, monoculture and diverse crops, dirt roads, windbreak trees, accent planting, dum-bung(small pond), natural small river, natural waterways, plastic film houses, one-storied houses, and pavilion. As a result of deriving the landscape adjectives from the main landscape elements, there were nine landscape adjectives that were consistent with experts and the public, including "clear" and "Artless" for rice paddies and fields, while the mismatched landscape adjectives were 'traditional'. The accent planting was a combination of landscape adjectives such as 'natural' and 'clear', while the windbreak trees was a consensus of all landscape adjectives. Only two adjectives, 'friendly' and 'wild', agreed on the dirt load, nine dum-bung(small pond), ten natural small river, nine duckery, eight one-storied houses, 10 pavilion, eight monoculture and diverse crops, and three natural waterways. The most common landscape adjectives were windbreak trees, pavilions, and natural small river, all 10 landscape adjectives. However, it is considered that only three of the 10 landscape types on the dirt road and the natural number are matched. Thus, additional management measures will be needed. In addition, it was analyzed that the most common landscape adjectives were "Artless" and "friendly" 13 times. The landscape adjectives of the organic farming complex responded by experts were analyzed to be suitable for natural, clear, zingy, silent, traditional, artless, friendly, wild and Leisurely, and consistent with the general public's opinion.

• Journal of Korea Water Resources Association
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• v.55 no.7
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• pp.531-543
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• 2022

Integrated water resources management (IWRM) has focused on efficient response to various water related disasters by climate change. In particular, more flexible usage of conventional water resources infrastructures is expected to provide an eco-friendly water management. Multi-purpose dams and water supply dams are well known as water management facilities for securing and supplying water in drought season. Recently, based on the report '2021 multi-purpose use of hydropower dams in Han river', contribution of hydropower dams on water resources management is becoming more significant beyond the traditional role of hydropower generation. In drought conditions, the dams control water supply depending on the pre-defined drought stages. In the case of multi-purpose dams, an operation standard during drought has been already prepared and applied; however, for the hydropower dams, specific standards are not fully prepared yet in South Korea. In this study, a method for calculation of standard water storage and discharge reduction of hydropower dams according to drought stage is newly proposed reflecting the characteristics of hydropower dams. The proposed method was applied to the hydropower dams in Han river, where six hydropower dams are located. A case study of the historical droughts occurred in 2014-2017 demonstrated that the proposed hydropower dam operation rule could improve the water supply stability under severe drought conditions compared to the conventional operations. In the future, the role of hydropower dams for water resources management is expected to become more important, and this study can be widely used for water supply planning such as drought response using hydropower dams.

• Korean Journal of Remote Sensing
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• v.39 no.6_3
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• pp.1747-1761
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• 2023

Wetlands, defined as lands periodically inundated or exposed during the year, are crucial for sustaining biodiversity and filtering environmental pollutants. The importance of mapping and monitoring their topographical changes is therefore paramount. This study focuses on the topographical variations at the Incheon River estuary wetland post-restoration, noting a lack of adequate prior measurements. Using a multi-temporal Sentinel-1 dataset from October 2014 to March 2023, we mapped long-term variations in water bodies and detected topographical change anomalies using a pixel-frequency approach. Our analysis, based on 196 Sentinel-1 acquisitions from an ascending orbit, revealed significant topography changes. Since 2020, employing the pixel-frequency technique, we observed area increases of +0.0195, 0.0016, 0.0075, and 0.0163 km² in water level sections at depths of 2-3 m, 1-2 m, 0-1 m, and less than 0 m, respectively. These findings underscore the effectiveness of the wetland restoration efforts in the area.

• Korean Journal of Ecology and Environment
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• v.51 no.2
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• pp.149-159
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• 2018

Twenty-nine wetlands (20 river type and 9 lake type wetlands) in Gyeongsangnam-do were investigated to understand the characteristics of fish assemblages by the wetland type and to suggest management strategies. As a result, $10.3{\pm}4.8$ species were collected from river type wetlands on average (${\pm}SD$) and $9.1{\pm}4.1$ species from lake type wetlands. Thus, there was no significant difference in the number of species between them (Mann-Whitney U test, P>0.05). However, the species that constitute the fish assemblage showed statistically significant differences between the two wetland types (PERMANOVA, Pseudo-F=2.9555, P=0.007). Furthermore, the species that contribute the most to each type of fish assemblage were Zacco koreanus (river type, 28.51%) and Lepomis macrochirus (lake type, 23.21%), respectively (SIMPER). The results of the NMDS analysis using the fish assemblage by place classified the species into three groups (river type, lake type, and others). The current wetland management is only focused on endangered species, but this study shows a difference in fish assemblage by wetland type. Therefore, a management system based information on endemic species, exotic species and major contribution species should be provided. Furthermore, the classification of some types of wetlands based on the present topography was found to be ambiguous, and wetland classification using living creatures can be used as a complementary method. This study has limitations because only two types of wetlands were analyzed. Therefore, a detailed management method that can represent every type of wetland should be prepared through the research of all types of wetlands in the future.

• Korean Journal of Ichthyology
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• v.27 no.2
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• pp.95-103
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• 2015

Egg development and early life history of the Korean spine loach, Cobitis tetralineata, were investigated in the present study. Adult fish were sampled using spoon nets at the Seomjin River in Jeongsan-ri, Bokheong-myeon, Sunchang-gun, Jeollanbuk-do, Korea, July 2013. Eggs were obtained after injecting Ovarprim into females. Eggs were then artificially fertilized using the Dry method in the laboratory. Mature eggs were slightly adhesive and transparent with grey coloring, and measured $1.04{\pm}0.03mm$ ($mean{\pm}SD$) in diameter. Hatching of the embryo occurred approximately 56 hours after fertilization at $25^{\circ}C$ of water temperature, and the average size of newly hatched larvae was about $4.6{\pm}0.11mm$ in total length. At fifth day after hatching, the larval full length reached $6.8{\pm}0.28mm$ on average and their yolk sac had been completely absorbed. At 17th day after hatching, larva entered the juvenile stage and reached $9.8{\pm}0.50mm$ in total length. At 100th day after hatching, the formation of Gambetta's zone of four line was complete and juveniles were similar in general appearance to adults, and they averaged $34.7{\pm}5.77mm$ in total length.

• Journal of the Korean association of regional geographers
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• v.14 no.4
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• pp.279-289
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• 2008

The purpose of this paper is to search for geomorphological landscape resources of Goryeong-gun, to provide fundamental data for their management through mapping their distribution, and to present their conservation and application plan. The results are as follow: Firstly, geomorphological landscape resources in mountain area are Misungsan and Jusan mountain of Goryeong-up, Sangbiri valley of Deoggok-myeon, and isolated hill of Gaejin-myeon. Secondly, geomorphological landscape resources in riparian area are natural wetlands such as Jinchonneup of Bu-ri Gaejin-myeon, Hochonneup and Dalseongseupji of Hochon-ri Dasan-myeon, Bongsanneup of Bongsan-ri Ugok- myeon; artificial wetlands following the construction of weir such as riparian wetland of Oe-ri Goryeong-up and Banun-ri Gaejin-myeon; meander core and abandoned channel of Banun-ri Gaejin -myeon, river cliffs such as Naegok-ri Goryeong-up and Weolo-ri Ugok-myeon; sand bars and braided channel of Yajeong-ri Ugok-myeon. Thirdly, Jinchonneup swamp area of Bu-ri Gaejin-myeon have characteristics of typical floodplain landform, and its conservation conditions is relatively satisfactory, and its accessibility to metropolis is great, so it is a good place to construct eco-park. And construction of inquiry learning place at Banun-ri Gaejin-myeon will increase the opportunity to observe environmental changes following incised meander cutoff and ecological affirmative functions of a weir.

• Journal of Wetlands Research
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• v.24 no.3
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• pp.155-160
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• 2022

The debate of South-North transboundary rivers must be expanded from the existing cooperation in water resources towards cooperation within ecosystem conservation. Regarding the Han and Imjin rivers confluence water system, the nature of the estuarine ecosystem must be conserved considering the aspect of climate change. Furthermore, the agenda of maintaining continuous inter-Korean communication and cooperation should focus on ecosystem conservation, including conserving migratory species that inhabit both Koreas. Notably, within the Han and Imjin rivers confluence, transboundary rivers are abundant legally protected species such as Grus vipio, Anser fabalis, Anser cygnoides, Platalea minor, Lutra lutra, Prionailurus bengalensis which suggests a strong need for a debate regarding habitat conservation. This study analyzed the ecosystem conditions and environmental aspects within the confluence of Han and Imjin rivers. In addition, this study provided step wise approach of ecosystem conservation that consider conditions for potential direct inter-Korean cooperation. The inter-Korean cooperation mentioned in this study will be developed into legitimate cooperation once the results from monitoring the ecosystem of transboundary rivers, awareness raising are exchanged.

• Korean Journal of Ecology and Environment
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• v.56 no.2
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• pp.151-160
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• 2023

Cyanobacteria Pseudanabaena strains are known to produce 2-MIB(odorous material) in freshwater systems, thereby causing problems in water use. However, their physiological responses to environmental factors in relation with 2-MIB production is not well explored. This study was conducted to evaluate the effect of temperature on the growth and 2-MIB production of Pseudanabaena redekei. The experimental cyanobacteria strains were separated from the Uiam Reservoir (North Han River) and cultured in the BG-11 medium. Temperature was set to 10, 15, 20, 25, and 30℃ for the experiment, in the reflection of the seasonal water temperature variation in situ. For each temperature treatment, cyanobacterial biomass(Chl-a) and 2-MIB concentration (intra-cellular and extra-cellular fractions) were measured every 2 days for 18 days. Both maximal growth and total 2-MIB production of P. redekei appeared at 30℃. While intra-cellular 2-MIB contents were similar (26~29 ng L^-1) regardless of treated temperatures, extra-cellular 2-MIB concentration was higher only in high temperature conditions (25~30℃), indicating that the extents of 2-MIB biosynthesis and release by P. redekei vary with temperature. The 2-MIB productivity of P. redekei was much higher in low-temperature conditions (10~15℃) than high temperature conditions (25~30℃). This study demonstrated that temperature was a critical factor contributing to 2-MIB biosynthesis and its release in cell growth (r=0.605, p<0.01). These results are important to understand the dynamics of 2-MIB in the field and thereby provide basic information for managing odorous material in drinking water resources.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.3
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• pp.23-43
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• 2020

The purpose of this paper is to create ecological values for urban rivers. For this, the paper looks into river bed structures and how nearby lands are used. This study was performed to set the specific sections for analysis through a field investigation of the infrastructure conditions, surrounding land use, and the inter habitat structure of Seongnaecheon(Stream). A total of 780 individuals from 31 species of wild birds appeared in Seongnaecheon(Stream). According to foraging guild's habitat, there were 9 species of water, 8 types of water edges, 5 types of crowns, 5 types of shrubs, 2 types of tree trunks, 2 types of birds of raptors, and 355 individuals of water, 243 shrubs, 90 crowns, 84 water edges and 5 raptors. Many water birds were observed at the site where the Seongnaecheon(Stream) sandy plains and wetland herbaceous area were developed and the open water was secured. Most of the forest birds appeared on levee slope connected with forest around and riverside with fewer facilities for use. The species diversity index of Shannon, the entire section of Seongnaecheon(Stream), was 2.2697 and the downstream ecological landscape conservation area of Seongnaecheon(Stream) was found to be useful as a habitat for wild birds in the city compared to other sections. Some sections of Seongnaecheon (Stream) had low species diversity index due to lack of green space and surrounding urbanization areas. In choosing target species, I researched the special features of the habitats and the habitation structure of wild birds in each zone. Regarding detailed plans, by classifying the breeding place & roosting site and the roosting site & shelter that took account of the inhabitation characteristics of the target species in different sections, this paper suggested the major plant species and multilayer planting structures. Moreover, this study proposed the development of habitats for water birds and forest birds along with the connection of the green network for improving the Eco-corridor linkage and inhabitation features in Seongnaecheon(Stream).