• Journal of People, Plants, and Environment
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• v.24 no.4
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• pp.389-401
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• 2021

Background and objective: The purpose of this study is to investigate the ecological status of six areas around Geumgang River that used to be farmlands before they were restored as a riverine ecobelt. This study aims to analyze the correlation between the location environment and ecological status of the sites to identify the environmental factors affecting them. Methods: The sites are classified into four types according to restoration: terraced paddy fields, flat paddy fields, artificial wetland, and landscape forest. The survey items were divided into land use status, plant ecology, and animal ecology. Results: In terms of plant ecology, terraced paddy fields showed favorable naturality with the rate of native species above 90% and the naturalization index below 10%. In terms of animal ecology, the total number of species found in these areas was biggest in terraced paddy fields, followed by flat paddy fields, artificial wetland, and landscape forest. Regarding species diversity, terraced paddy fields also showed abundant species with an average of 1.05 to 1.09. The results of the correlation analysis showed that the forest area around the sites had the most significant effect on species diversity. The grassland and open water area showed a positive correlation with the total number of animal species and the number of dragonflies, confirming that the marshy grassland had a positive effect. As the cultivated land and urbanized area around the sites increased, it had a negative effect on the distribution of native species and the number of animal species that appeared, and a positive effect on the naturalization index. Conclusion: It is necessary to establish preemption and restoration plans for sites such as grasslands adjacent to the forest and terraced paddy fields in order to promote resilience of the diverse species returning to the purchased lands.

• Environmental and Resource Economics Review
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• v.28 no.4
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• pp.645-673
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• 2019

The hypothetical nature of stated preferences can lead to a hypothetical bias that might work as a normative pressure, influencing survey responses. This paper aims to test the impact of social desirability bias by comparing economic estimates based on both subjective and objective valuation questions. The case study is about an urban riverine restoration project in Deajeon, South Korea. As valuation methods both contingent valuation and choice experiments were comparatively applied. Based on a nationally representative sample of 1,000 respondents, the test results offered contrasting conclusions between two test approaches. Accroding to the estimation results based on the conventional valuation, the marginal willingness to pay estimates are 10,500 KRW from CV; and 18,600 KRW for improving water quality, 2,200 KRW for the inside view, 8,900 KRW for the outside view, and 5,800 KRW for biodiversity from CE. A segmentation-based approach is a conventionally used method, which showed a limited impact of social desirability on willingness to pay estimates. The alternative parameterization-based approach measures a model-wide impact of social desirability, proving a significant bias. Although the study positioned a cheap-talk statement before the valuation section of the survey questionnaires, which might have pre-screened the bias, the overall implications of the results suggest a caution in reducing and observing hypothetical bias. There might remain a significant and substantial hypothetical bias even after cheap-talk, particularly in situations with strong social desirability, so that the potential role of objective valuation questions is guaranteed.

• Journal of Ecology and Environment
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• v.30 no.2
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• pp.171-177
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• 2007

Korean rivers and their surrounding environments have been used excessively for rice production in the past and more recently for construction of urban areas to accomodate the rapidly increasing population. Affected Korean rivers experience dramatic fluctuations in their water levels and have faster currents compared with those in other countries. In order to restore more natural conditions in rivers experiencing such conditions, we employed a partial restoration method, which is designed to achieve physical and biological stability simultaneously. Concrete blocks were introduced to increase the river's physical stability during floods, and terra cottem, a soil enhancer, was used to reduce water loss due to intense heat. These interventions increased the river's ability to hold water and thereby promoted plant growth. This restoration method increased vegetation coverage and species diversity in treated areas, and changed the species composition in treated areas to more closely approximate that of the control site. These results suggest that this method is effective in restoring damaged habitats to more natural conditions.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.535-545
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• 2011

This study was carried out to suggest the baseline data necessary for vegetation restoration by naturalness assessment of riverine wetland within stream corridor. We selected stream reach both of near nature and urbanized by Nonsan stream and Hongchun river as experimental site. Composition of vegetation community and land use pattern between two sites indicated considerable difference, which imply for many different watershed property and process disturbed each other at river ecosystem. Naturalness of the sampled reaches showed that near nature is in better condition for riverine wetland than urbanized of all two sites. However, the prevalence index of Hongchun river within its natural state was lower than that of Nonsan stream, because the index included some vegetation communities occurred at upland fringe and bank slope. In conclusion assessment system using prevalence index would be considered an effective method for evaluating of natural states of riverine wetland.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.2
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• pp.11-25
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• 2001

A wetland is an ecosystem which is the most useful and highly-energetic transition area. This study has been carried out to classify and identify the various types of wetlands in Korea. The main objective of this study are 1) defining and classifying of wetlands, and 2) identifying the wetlands characteristics, and 3) studying cases on the natural wetlands such as Han river, DMZ(Demillitarized Zone), Upo wetland and Yong(Dragon) wetland. The results as follows： 1) Development of the indices for identifying and classifying wetlands in encompassing in such as Ramsar Conference, US NWI(National Wetlands Inventory), Hydrogeomorphic system. 2) Development on the classifying method on the wetlands in the level of supersystem, system, subsystem, class and subclass. The systems include Palustrine and Riverine, and the subsystems are Seasonal, Permanent(Palustrine) and Impersistent, Lower perennial, Impersistent (Riverine). 3) Finally, we find out Young wetland is Palustrine/Permanent/Slope/Persistent, and Upo wetland consists of various types of wetlands, those are, Palustrine/Permanent/Depression/Forest Deciduous, Palustrine/Permanent/Depression/Shrub Deciduous, Palustrine/Permanent/Depression/Persistent, Palustrine /Permanent/Depression/Hydrophytes, and Lacustrine/Permanent/Openwater/Hydrophytes. The taxonomy of this study stems from identifying and classifying wetlands with indices mainly based on hydrologic features and substrates. So, it is needed that consequent studies are to be performed with various viewpoints. And the studying cases were limited because of the restricted entrance into the DMZ, And, we selected only 10 crucial sites in Han river as the subject for wetlands regulation and creation. And, for advanced studies, drawing up inventory and mapping are necessary.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.6
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• pp.153-163
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• 2009

This study was carried out to offer ecological restoration plan of local streams by analyzing the vegetation and flora around four local streams (Pungchoncheon, Namchangcheon, Ganggicheon, Woncheoncheon) in Namwon. Flora and vegetation investigation was done at April 2007 to August 2007, and June 2009. The 194 of vascular plants were identified which contain 53 families, 143 genera, 194 species. The Family frequencies arranged by the order of Family Compositae (14.4%), Family Gramineae (13.4%) Family Leguminosae (6.7%) and Family Polygonaceae (5.2%). The naturalized plants were listed as 33 species, and their naturalization ratio and urban index were found to be 17.0%, and 12.2%, respectively. In this study a total of 21 relev$\acute{e}$s collected and analyzed. 6 plant communities are differentiated : Riverine softwood forests (Phragmites japonica-Salix gracilistyla community), Perennial herb vegetations on lotic water zone (Phragmites japonica community, Phalaris arundinacea community), Perennial herb vegetations on lentic water zone (Persicaria thunbergii-Typha orientalis community, Phragmites communis community), Annual or biennial vegetations on waterside (Persicaria thunbergii community). Species showing the higer value in the plant communities were Persicaria thunbergii, Phragmites japonica, Artemisia princeps, Humulus scandens, Bidens frondosa, Oenanthe javanica, Agropyron tsukusinense var. transiens, Stellaria aquatica, and Lactuca indica var. laciniata.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6B
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• pp.387-397
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• 2012

In this study, an ecological fragmentation improvement effect from different riverine ecobelt width was analyzed. The target river for this study is the Hongcheon river in Kangwondo. This section of 11 km among the Hongchenon river was reported to be seriously fragmented in the previous literatures. The Hongcheon river of 11 km was divided longitudinally into subsections of 1 km. The analysis through map and aerial photograph as well as field surveys were performed in 11 subsections(A-K). Using the fragmentation index, the connectivity fragmentation such as river bank, road, and land use and the ecological functional fragmentation were evaluated. The results showed that I-section has the highest fragmentation rate. The Hongcheon river in the present status without ecobelt was analyzed to has the fragmentation of 2nd rate from the mean fragmentation value of 11-subsections. Also, when the riverine ecobelt of 10 m-50 m was restored, the improvement effect of connectivity fragmentation was relatively small, while for the ecological fragmentation, the improvement effect of 12.4-25.1% was predicted. Also, the ecobelts of 10 m and 30 m were evaluated to have a relatively great improvement effect. Especially, for the ecobelt of 30m width, the fragmentation rate was mitigated form 2nd rate to 3rd rate.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.6
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• pp.61-74
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• 2004

Hydraulic engineers and scientists working on river restoration recognize the need for a deeper understanding of natural streams as a complex and dynamic system, which involves not only abiotic elements(flow, sediments) but also biotic components. From this point of view, the role played by riverine vegetation dynamics and flow conditions becomes essential. Hydro-mechanic interaction between flow and flexible plants covering a river bed is studied in this paper and some previous works are discussed. Measurements of turbulence and flow resistance in vegetated open channel were performed using rigid and flexible tube. Measuring detailed turbulent velocity profiles within and above submerged and flexible stems allowed to distinguish different turbulent regimes. Some interesting relationships were obtained between the velocity field and the deflected height of the plants, such as a reduced drag coefficient in the flexible stems. Turbulent intensities and Reynolds stresses were measured showing two different regions : above and inside the vegetation domain. In flexible vegetated open channel, the maximum values of turbulent intensities and Reynolds stresses appear above the top of canopy. Method to predict a flow resistance in flexible vegetated open channel is developed by modifying an analytical model proposed by Klopstra et al. (1997). Calculated velocity profiles and roughness values correspond well with flume experiments. These confirm the applicability of the presented model for open channel with flexible vegetation. The new method will be verified in the real vegetated conditions in the near future. After these verifications, the new method should be applied for nature rehabilitation projects such as river restorations.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.44-54
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• 2010

In this study, a comprehensive exploration and evaluation of washland candidate locations by means of field monitoring as well as spatial analysis in six major river system (Han, Nakdong, Nam, Geum, Youngsan, and Seomjin Rivers). Washland(in other words, river detention basin) is an artificial wetland system which is connected to streams or rivers likely to riverine wetlands. Major purpose of washland creation is to control floodings, water supply and purification, providence of eco-cultural space to human and natural populations. Characteristics and functions of riverine wetlands can be expected as well, thus it is believed to be an efficient multi-purpose water body that is artificially created, in terms of hydrology and ecology. Geographical information and field monitoring results for the washland candidate locations were evaluated in 2009, with respect to optimal location exploration, ecosystem connectivity and educational-cultural circumstances. A total of $269\;km^2$ washland candidate locations were found from spatial analysis (main channel of Rivers South Han, 71.5; Nakdong 54.1; Nam, 2.3; Geum, 79.0; Youngsan 46.4; Seomjin 15.7), and they tended to be distributed in mid- to lower part of the rivers to which tributaries are confluent. Field monitoring at 106 sites revealed that some sites located in the Rivers Nam and Geum is appropriate for restoration or artificial creation as riverine wetlands. Several sites in the Nakdong and Seomjin Rivers were close to riverine wetlands (e.g., Upo), habitats of endangered species (e.g., otters), or adjacent to educational facility (e.g., museums) or cultural heritages (e.g., temples). Those sites can be utilized in hydrological, ecological, educational, and cultural ways when evidence of detailed hydrological evaluation is provided. In conclusion, determination of washland locations in the major river basins has to consider habitat expansion as well as hydrological function (i.e. flood control) basically, and further utility (e.g. educational function) will increase the values of washland establishment.

• Journal of Ecology and Environment
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• v.35 no.2
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• pp.123-129
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• 2012

Salt marsh is an important transitional zone among terrestrial, riverine, and marine ecosystems and is a productive habitat that interacts extensively with adjacent landscape elements of estuarine and coastal ecosystems. Nowadays, in addition to various human activities, a variety of natural processes induce changes in salt marshes. This study aims to provide background information to restore disturbed salt marshes and to propose their ecological restoration using seed banks. The study area is a prepared area for the Gwangyang Container Port located in the southern Korea. This area was formed by accumulating mud soils dredged from the bottom of the forward sea. This land was created in a serial process of preparing the Gwangyang container port and the salt marsh was passively restored by seeds buried in mud soil dredged from seabed. As a result of stand ordination based on vegetation data collected from the land, stands were arranged according to tolerance to salinity in the order of $Suaeda$ $maritima$, $Salicornia$ $europaea$, and $Phragmites$ $communis$ communities on the Axis 1. Landscape structure of the projected area was analyzed as well. Edges of the projected area were divided from the marginal waterway by the dike. Four types of vegetation appeared on the dike: $Alnus$ $firma$ plantation, $Robinia$ $pseudoacacia$ plantation, $Lespedeza$ $cyrtobotrya$ plantation, and grassland. In the more internal areas, two types of vegetation sequences appeared: $Aster$ $tripolium$ community-$Suaeda$ $glauca$ community-$Salicornia$ $europaea$ community sequence and $Aster$ $tripolium$ community-$Suaeda$ $maritima$ community-$S.$ $europaea$ community sequence. Mixed community showed the highest species diversity (H' = 0.86) and $S.$ $europaea$ community showed the lowest (H' = 0.0). Evenness is the highest in Mixed community (J' = 2.26) and the lowest in $S.$ $maritime-S.$ $europaea$ community (J' = 0.0). Several plant communities were successfully established on the land created by mud soil dredged from the bottom of Gwangyang Bay. Moreover, community diversity in this area approached a similar level with those from other studies involving natural salt marshes. Therefore, restoration effect based on community diversity obtained in our study can be evaluated as a successful achievement. In this respect, although most salt marshes in Korea and other places worldwide have been destroyed or disturbed by excessive land use, feasibility of seed bank as a restoration tool is greatly expected.