• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.365-372
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• 2018

The Wintering Waterbird Census of Korea was started in 1999 and monitors 200 major migratory sites in South Korea. Waterfowl counts have been undertaken for more than 20 years since; however, a limited number of studies have analyzed the temporal patterns of waterfowl population. In this study, we analyzed population size changes of wintering whooper swan (Cygnus cygnus) at 112 monitoring sites from 2001 to 2018. The average number of whooper swans was $4,296{\pm}42.66$ and there was a trend for an increase in population size across the survey period. We found that the population in the Nakdong River Estuary, one of the major wintering sites over 18 years (26.22% of the national population), had rapidly decreased (-0.77% per year). Conversely, the whooper swan population in the Junam Reservoir and Sihwa Lake increased (+1.64%, +0.54% per year, respectively). Estuaries showed the highest dominance of whooper swans among the five different habitat types, accounting for 32.13% of the population. Reservoir/lakes had 30.60% of the total population and reclaimed lakes(18.24%), river (13.11%), and coast (5.93%) followed. The annual distribution of the whooper swan population in South Korea has been affected by various habitat conditions resulting from human activities and urbanization. To better understand the complex factors that can cause rapid changes in wintering waterfowl populations, it is necessary to integrate the data from the bird census program with environmental conditions to conduct in-depth pattern analyses over longer time periods.

• Korean Journal of Ecology and Environment
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• v.52 no.2
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• pp.161-170
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• 2019

Invasive alien plants were identified and recorded in Ulsan city based on field surveys and related literatures. These plants consisted of 147 taxa in total, belonging to 30 families, 93 genera, 144 species, 2 subspecies and 1 variant. The family of Asteraceae was predominant with 42 taxa, followed by Gramineae with 27 taxa and Leguminosae with 15 taxa. According to the result of life-form based distribution analysis revealed that 62 taxa (42.2%) were annual plants, 48 taxa (33.6%) were perennial plants, 34 taxa (23.1%) were biennial plants, and 3 taxa (2%) were woody perennials. Compare to other administrative districts in Korea, prevalence of invasive alien plants in a certain city of Ulsan showed the seventh highest species number followed after Jeju, Gyeonggi, Jeonnam, Incheon, Seoul and Gangwon. On the basis of the results from the country origin analysis, two dominating taxa were introduced from Europe and America, 55 taxa and 51 taxa respectively. The spreading grade of alien plants was elucidated in order of 1 grade (PS) 67 grade (21.1%)>2 grade (MS) 31 taxa (21.1%)>5 grade (WS) 18 taxa (11.6%)>3 grade (CS) 17 taxa (11.6%)>4 grade (SS) 14 taxa (9.5%). Ulsan city is one of a pivotal conduit for the introduction of invasive alien plants. Thereby, reliable management plans are required to monitor these species.

• Korean Journal of Ecology and Environment
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• v.52 no.1
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• pp.65-70
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• 2019

A total of 23 individuals of glass eel (Anguilla japonica) were investigated from two estuarine barrages of the Nakdong River in 2016. It was observed that most individuals migrated through the eastern barrage, compared to the western. Individual numbers differed significantly along the corridor modification of the barrages; for example, the number of individuals was two to three times higher after the modification. These results indicate that modification of fish way and lock gate for has facilitated migration of glass eel, and our study potentially offers the operation strategy of estuarine barrage in order to induce more active migration of glass eel.

• Korean Journal of Ecology and Environment
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• v.52 no.1
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• pp.1-8
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• 2019

River water quality and organisms have a very close relationship with the human living environment and health, so it is very important to ensure and maintain the ecological integrity of the aquatic ecosystem. In that sense, benthic diatoms have relatively little mobility, can explain the effects of long-term exposed pollution sources, and are very suitable indicator organisms for river ecosystem evaluation. Diatom ecologists have been developed various diatom indices to assess water quality and stream ecosystem over the world. However, they so far have insufficient identification of taxa, are strongly regional, and are difficult to apply as they are domestically. Unfortunately, there has not been developed an independent diatom index suitable for the Korean stream. Therefore, management of water quality and aquatic ecosystem suitable for domestic rivers can be made, and development or improvement of comprehensive multivariate diatom index for the integrated assessment of water quality and aquatic ecosystem is urgently needed.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.453-460
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• 2020

Bolboschoenus planiculmis is an important prey species for winter migratory birds in the Nakdong River Estuary region, but its population has declined in the last decade due to a physio-chemical shift. To identify the growth and development characteristics of B. planiculmis, we carried out an experimental survey on the aboveground and belowground sections of B. planiculmis specimens in the Eulsuk tidal flat from April to September 2019. We divided the belowground area into two groups: a vegetation group in which B. planiculmis exists and a non-vegetation group in which B. planiculmis does not exist and measured the rate of tubers. We observed a 45% appearance frequency in the vegetation group and only a 5% frequency in the non-vegetation group, indicating that there were no supplies for plant growth. The mean density, length, and biomass of B. planiculmis aboveground were 166.90±149.62 n m^-2, 44.39±5.45 cm, and 67.63±54.46 g DW m^-2, respectively, which was approximately half of those obtained from the study in the Eulsuk tidal flat in 2002. Tuber number was the highest in the 15~25 cm deep layer(41.50%). The mean number of total tubers belowground was related to different sediment conditions(FS: flat surface, DS: disturbed surface) 251.75±16.86 n pot^-1 for FS and 171.00±25.18 n pot^-1 for DS, which was significantly different(total tubers: p<0.005). The mean biomass of B. planiculmis above-ground was 21.11±1.60 g DW pot^-1 for FS and 15.41±1.38 g DW pot^-1 for DS, which was significantly different(p<0.05). This research provides primary materials for the restoration of the Nakdong River Estuary, wintering sites for migratory birds, and protection of B. planiculmis.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.331-335
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• 2020

The red swamp crawfish (Procambarus clarkii) is native to northeastern Mexico and south-central United States. But the species has been introduced to other parts of the world, and cause ecological problems including habitat destruction and competition with indigenous species. In this study, we identified the distribution of P. clarkii in the freshwater system in Korea. P. clarkii were collected in the field sampling and it is assumed that they have settled in major domestic water systems of Korea including six points in the Yeongsangang River, five points in the Mangyeonggang River, two points in the Seomjingang River, and one point in the Geumgang River. In particular, more than 20 individuals were found in Seobongri, Wanjugun and Mosanri, Hampyeonggun, which are believed to form a relatively large population. Considering high mobility and environmental adaptability of the species, the possibility of their dispersal to other water systems is very high. Therefore, continuous monitoring and assessment of their distribution and potential spread are required and effective management to remove them policy is needed to prevent damage in the Korean ecosystem.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.390-407
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• 2020

This study was carried out to evaluate the restoration effect in the restored Yangjae stream and to draw up an adaptive management plan based on the results. As the result of evaluation on the restoration effect, the restored Yangjae stream was evaluated with low naturalness in both terms of the morphology of the stream and the composition and spatial distribution of vegetation. The diverse functional groups were introduced in the vegetation restoration, but the flooding regime, which is significant in the spatial distribution of riparian vegetation, were not correctly reflected. Exotic species or species that were not ecologically suitable for the location were introduced on the embankment and thus a measure to improve those problems is required. As the ecological principle was not reflected in the restoration plan, the stream was constructed as the double terrace structure. Therefore, the width of the waterway was narrowed further, and the waterfront was not designed to accommodate changes from flooding disturbance, making the micro-topography of the stream simpler and the naturalness lower. The adaptive management plan was prepared to improve those problems, and a plan for creating an ecological network was recommended to enhance the restoration effect.

• Korean Journal of Ecology and Environment
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• v.54 no.2
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• pp.120-124
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• 2021

In order to understand the vegetative role of Glycine soja, we studied the basic physiological characteristics between Glycine soja and Glycine max. For this study, the light intensity (μmol m^-2 s^-1) on leaf surface, leaf temperature (℃), transpiration rate (mmol m^-2 s^-1), photosynthetic rate (μmol m^-2 s^-1), substomatal CO₂ partial pressure (vpm) of Glycine soja and Glycine max were measured, and the quantum yield, photosynthesis rate per substomatal CO₂ partial pressure were calculated. In the results of simple regression analysis, the increasing quantum yield decreases leaf temperature both of Glycine soja and Glycine max and the increasing leaf temperature decreases transpiration rate in case of Glycine soja. However, in case of Glycine max, the increasing leaf temperature decreases substomatal CO₂ partial pressure, photosynthetic rate, and photosynthetic rate per substomatal CO₂ partial pressure as well as transpiration rate. Also, increasing transpiration rate increases substomatal CO₂ partial pressure while decreases photosynthetic rate per substomatal CO₂ partial pressure. Thus, Glycine soja is relatively more easily adaptable to severe environments with low soil nutrients and high light levels. Compared to Glycine max susceptible to water loss due to a water-poor terrestrial habitat, the physiological traits of Glycine soja has a high average transpiration rate and are less susceptible to water loss will act as a factor that limits the habitat according to soil moisture.

• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.408-426
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• 2020

This study aims to establish the national strategy for biodiversity conservation by analyzing the current status of ecodiversity as the foundation of biodiversity conservation. Furthermore, this study has another purpose of preparing the measures for conservation and restoration of biodiversity. Ecodiversity was discussed as the basis for conserving biodiversity. Five climate zones and 14 climatic regions, eight plant geographic regions, three massifs and major geologic series, horizontal and vertical topographic conditions, 16 ecoregions, major ecosystems including forest, river and streams, wetlands, coast and marine, agriculture, and urban esosystems, and land use types were discussed as the element of the ecodiversity. In terms of biodiversity conservation, the actual conditions of each ecological unit were reviewed and measures were proposed to reduce biodiversity loss. Destruction and fragmentation of habitat, poor ecosystem management due to socioeconomic changes, the effects of exotic species and chemicals, and climate change were discussed as the major factors causing biodiversity loss. Systematic monitoring based on scientific principles and ecological restoration based on those monitoring results were recommended as measures for biodiversity conservation.

• Korean Journal of Ecology and Environment
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• v.55 no.3
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• pp.244-250
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• 2022

The changes in COD, TOC, T-P, and T-N concentrations were investigated for 2 years in the constructed wetland of Sookcheon, which was installed to improve the water quality of Daecheong reservoir in South Korea. In order to evaluate the pollution level of sediments in the wetland, settling velocity of particulate material (4 times) and sedimet material contents (6 times) were measured. COD and TOC concentrations increased slightly as they passed through wetlands, and T-N and T-P concentration tended to decrease. The material content (COD, T-P, T-N) of aquatic plants was higher in floating-leaved and free-floating macrophytes than emergent macrophytes. As a result of measuring the sedimentation rate of suspended materials, most of the suspended materials introduced into constructed wetlands were sedimented at a rapid rate in the first sedimentation site. In addition, sediment pollution of T-P and T-N in constructed wetland was in severe pollution. The sediments containing a large amount of T-P and T-N were eluted by physical and chemical environmental changes, which is likely to act as internal pollution sources in wetlands.