• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.361-371
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• 2005

The objective of study was to diagnose integrative ecological health of Daejeon Stream, one of the tributaries of Guem River, during May 2004 ${\sim}$ April 2005. The research approach was primarily based on a Qualitative Habitat Evaluation Index (QHEI) and the Index of Biological Integrity (IBI) using fish assemblage. These outcomes were compared with conventional chemical dataset. For the experiment, four sampling sites were chosen from Daejeon Stream and long-term water quality data during 1995 ${\sim}$ 2004 (obtained from the Ministry of Environment) were analyzed in the spatial and temporal aspects. For the biological health assessment, we developed a stream health assessment model (SHA model) far regional applications. We found that current water quality conditions, based on the COD, BOD, TN and TP, were enhanced by 1.6 ${\sim}$ 5.3 fold over the period of 1995 ${\sim}$ 2004 and that the parameters showed a typical longitudinal decline from the upstream to downstream reach. The differences of water quality between the two reaches were more than 4.4 times, indicating a large spatial variations within the stream. The health conditions, based on the SHA model, averaged 23 and varied from 20 to 26 depending on the sampling stations. Values of the QHEI varied from 39 (Poor condition) to 124 (Cood condition)and values of QHEI in the reach of S2 ${\sim}$ S4 had significantly lower than in the headwater site (S1). Also, biological stream health, based on the criteria of US EPA (1993), was judged as 'Poor condition', in the S4 where TN, TP, BOD and COD were highest. In the meantime, maximum value of SHA (26) was found in the upstream reach (S1) where the water quality and QHEI were best. We also found that compositions of sensitive species showed a linear function with water quality conditions and this pattern was evident in the tolerant species. Thus, the biological stream health, based on the SHA model, matched well water chemistry. Overall outcomes suggest that the biological health impact was a function of chemical degradation and physical habitat quality in the stream.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.142-146
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• 2016

The purpose of this study is to evaluate topographic characteristics revealed in the predicted distribution areas of Aporia crataegi, according to climate change. Towards this end, this study compared the differences of topographic factors, such as altitude, mountain slope and the aspect of slope, in the distribution areas with different potential inhabitation possibilities of the Aporia crataegi. The inhabitation possibilities of the Aporia crataegi were different, according to altitude and topographic slope, and the inhabitation possibility is judged to be affected more by the topographic conditions including altitude and mountain slope than by the aspect of slope. Especially, the inhabitation possibility of the Aporia crataegi was higher in the higher altitude area, as time goes on furthermore. The reason is that the current climate environment, which is suitable for the potential inhabitation of the Aporia crataegi, is forecast to be formed with an area with high altitude. Although the difference in the aspect of slope was not statistically significant according to inhabitation possibility, the reason why the inhabitation possibility of the Aporia crataegi varies in the mainly southeast slope is conjectured to be derived from the warmer heat environmental condition to grow from a larva into an imago. The result drawn in this study is expected to be utilized as basic data to establish a policy soundly preserving and managing the habitat of biospecies in consideration of climate change and topographic conditions in the natural ecosystem field by using the already built up various biological resources information.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.130-142
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• 2007

This study was to examine impacts of turbid water on fish community in the downstream of Yongdam Dam during the period from June to October 2006. For the research, we selected six sampling sites in the field: two sites were controls with no influences of turbid water from the dam and other remaining four sites were the stations for an assessment of potential turbid effects. We evaluated integrative health conditions throughout applications of various models such as necropsy-based fish health assessment model (FHA), Index of Biological Integrity (IBI) using fish assemblages, and Qualitative Habitat Evaluation Index (QHEI). Laboratory tests on fish exposure under 400 NTU were performed to find out impact of turbid water using scanning electron microscope (SEM). Results showed that fine solid particles were clogging in the gill in the treatments, while particles were not found in the control. This results indicate that when inorganic turbidity increases abruptedly, fish may have a mechanical abrasion or respiratory blocking. The stream health condition, based on the IBI values, ranged between 38 and 48 (average: 42), indicating a "excellent" or "good" condition after the criteria of US EPA (1993). In the mean time, physical habitat condition, based on the QHEI, ranged 97 to 187 (average 154), indicating a "suboptimal condition". These biological outcomes were compared with chemical dataset: IBI values were more correlated (r=0.526, p<0.05, n=18) with QHEI rather than chemical water quality, based on turbidity (r=0.260, p>0.05, n=18). Analysis of the FHA showed that the individual health indicated "excellent condition", while QHEI showed no habitat disturbances (especially bottom substrate and embeddeness), food-web, and spawning place. Consequently, we concluded that the ecological health in downstream of Yongdam Dam was not impacted by the turbid water.

• Korean Journal of Ecology and Environment
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• v.42 no.4
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• pp.422-431
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• 2009

This study was to provide basic data for aquatic ecosystem research using fishes. Field sampling was carried out at five selected sites of Gap Stream, and fish samples, especially for a selection of sentinel species were collected three times in June, September, and October 2007. We analyzed total length distribution of Zacco platypus in relation with the season and the sampling sites, and then compared with total body weight, condition factor (K), and age distribution of the fish. The fish population data were compared with physico-chemical water quality, obtained from the Ministry of Environment, Korea. Water quality analysis showed a significant nutrient enrichment, based on total nitrogen (TN) and total phosphorus (TP), and organic matter pollution, based on biological oxygen demand (BOD) and chemical oxygen demand (COD) in the Site 5, which is directly influenced by wastewater disposal plant (WDP). Population analysis of the sentinel species showed that the total number of individuals, age distribution, and the population size-structure were influenced by the effluents from the WDP, and that reproductive failure of young-age population were evident in Site 5. According to the relation analysis of total weight to K, the disturbed population was mainly attributed to combined effects of habitat modifications and chemical degradations. Regression analysis of K values against water quality parameters showed significant (p<0.05) positive relations with nutrient and organic matter contents. Our data suggest that the population structure using a sentinel fish species reflected the ambient water quality in the stream and that diagnosis of aquatic ecosystem health using Z. platypus population may be practical for water resource and ecosystem conservations.

• Ocean and Polar Research
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• v.43 no.2
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• pp.73-88
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• 2021

The community structure and health status of macrobenthos assemblages were investigated in the subtidal area of the Nakdong River estuary, Southern Coast of Korea. Benthic fauna samples were collected seasonally at 8 stations in the subtidal area of the Nakdong River estuary from February 2013 to October 2015. During the survey, a total of 380 species and 4,603 ind./m² of macrobenthos in all sampling areas were collected. The major dominant species were the polychaetes Minuspio japonica, Pseudopolydora kempi, Heteromastus filifomis, Capitella capitata, the amphipod Grandidierella japonica and the bivalvia Arcuatula senhousia. Some species of polychaetes found in the study area consisted of opportunistic species that showed high densities when habitat condition was poor. On the other hand, macrobenthos assemblages in the study area were divided into brackish water and marine groups. Abundance was high in the brackish group, while the number of species and diversity index were high in the oceanic group. The three indices (AMBI, M-AMBI, and BHI) in the assessment of health levels based on the ecological characteristics and number of species in macrobenthic were commonly shown to be in good condition in the group of oceanic stations, while relatively poor conditions were reflected in the group of brackish stations. Compared to other indices, the M-AMBI index of the three indices for health assessment was considered to be a relatively more suitable one to assess benthic ecological conditions.

• Journal of Environmental Impact Assessment
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• v.22 no.3
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• pp.241-254
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• 2013

The nutria(Myocastor coypus) that is originated from South America is a representative Invasive alien species in Korea. invasive alien species is one of the biggest causes for the loss of biodiversity and it may threaten the conservation and function of ecology as well as the welfare of mankind. Intense habitation has been made around the Nakdong River basin area that this study has analyzed the habitat density of nutria for the subject of 3 survey sites in the Nakdong River basin area. As a result of survey on habitation density in 2011 and 2012, under St.1 it was shown $2.01{\pm}0.21$/ha in 2011 and $0.69{\pm}0.55$/ha in 2012. Under St.2, it was shown $0.91{\pm}0.37$/ha in 2011 and $0.55{\pm}0.39$/ha in 2012. Under St.3, it was shown $5.31{\pm}0.72$/ha in 2011 and $3.99{\pm}2.31$/ha in 2012. The wet survey areas of St.1 and St.3 had shown relatively high habitation density compared to St. 2, the river survey area, and the average annual habitation density of the survey area was $2.74{\pm}2.29$/ha in 2011 and $1.74{\pm}1.18$/ha in 2012 that it has shown slightly reducing trend. As a result of measuring the morphology by capturing the habitation individuals, the average body length of adults is $92.23{\pm}9.41cm$, the length from the head to body for $53.90{\pm}5.15cm$, tail length for $38.33{\pm}4.83cm$, hind foot length for $13.82{\pm}1.00cm$, front foot length for $6.02{\pm}0.56cm$, and weight for $5.48{\pm}1.08kg$. As a result of comparing the types between genders, male showed a slightly higher figure in all parts compared to female and it showed significantly difference in total body length, head-body length, front foot length and total weight. As a result of analysis for each head-body length, other measured parts, weight and relativity for each measured part, all bodily part is shown to have the higher volume of correlations. The condition index of individuals in the survey area was shown in the average of $35.67{\pm}4.78$ with female for an average of $36.60{\pm}5.19$ and male for an average of $34.73{\pm}4.34$. The winter temperature in the southern area of Korea is considered for not greatly impacting on the habitation and development of nutria that, if there is no artificial control, it is considered to have certain concern of showing drastic breeding and territory expansion for the habitation group.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.498-507
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• 2006

The main objective of present study was to evaluate how seasonal rainfall influenced natural habitat conditions of 10 metric habitat variables along with ionic conditions and suspended solids in the Woopo Wetland during August 2002-July 2003. Largest spatial variabilities in total suspended solids (TSS) occurred during the summer monsoon and the inorganic suspended solids (ISS), expressed as a inorganic proportion of total solids, showed linearly increasing trend from the upstream to downstream. This phenomenon was mainly attributed to counter flow of turbid water from the main Nakdong-River. During the flooding, ISS : TSS ratio showed large increases (92%) in the downstream than the upstream (43%). For this reason, transparency declined (mean=0.13 m, range=0.08-0.21 m) largely in the downstream reach and thus, chlorophyll-a concentration showed low values (range: $4.2-8.6\;{\mu}g\;L^{-1}$), indicating a direct influence on primary productivity or algal growth by inorganic turbidity. In the 2nd survey, ISS averaged 4.0 mg $L^{-1}$ (3.3-4.8 mg $L^{-1}$), thus the ISS decreased by 14 fold, compared to the ISS in the 1st survey during the flooding, while organic suspended solids (OSS) values were greater than those of ISS, indicating a dominance of organic solids. This condition was similar to solid contents in the 3rd survey, but showed a large difference compared to the 4th survey during the growing season. Habitat health assessments, based on 10 metric habitat variables, showed that QHEI values were greatest in the growing season (May) than any other seasons and largest spatial variations occurred in the 2nd survey. Overall, dataset suggest that seasonal episodic flooding during the monsoon may largely contribute nutrient cycling and sediment contents in the Woopo Wetland and Topyung Stream.

• Journal of Wetlands Research
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• v.20 no.1
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• pp.27-34
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• 2018

Reproductive phenology and physiological responses of Epilobium hirsutum L. to moisture content and nutrient content of soil were analysed in order to obtain basic data for effective conservation and restoration. Epilobium hirsutum L. is a perennial plant. But Epilobium hirsutum L. grew reproductively in all moisture and nutrient gradients. Flower bud, flowers and peduncle were respectively ripened in earlier under highest moisture condition and highest nutrient condition. And, number of flowers and peduncle were more quickly increased under highest moisture condition and highest nutrient condition. Chlorophyll content was high under highest moisture condition and higher middle moisture condition. However, we found no significant difference of chlorophyll content regard to nutrient gradients. There was no difference in minimum chlorophyll fluorescence among all moisture and nutrient gradients. The photochemical efficiency values of PS II were 0.75 in all moisture gradients, and it was 0.78 in highest nutrient gradient. The chlorophyll content of Epilobium hirsutum L. increased as the moisture content increased, and the Fv/Fm value increased as the organic matter increased. Our results showed that high moisture and nutrient content of soil advance their breeding season and promote reproductive growth. It might be important basic informations for the maintenance of population and the management of habitat of Epilobium hirsutum L. an endangered plant species.

• Korean Journal of Environment and Ecology
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• v.34 no.3
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• pp.216-223
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• 2020

This study investigated the ecological characteristics of Coreoperca herzi at Jaho stream from September 2018 to August 2019. This species inhabited riffle and midstream of the stream, where the riverbed structure was mostly covered with cobble and pebble. The depth of the habitat was 32-157 cm, and the velocity of stream fast at 0.64±0.28 (0.32-1.28) m/sec. The gender ratio of females to males was 1:0.95. The age according to the frequency analysis of total length indicated that the group with 42-80 mm in total length was one year old, the group with 80-130 mm was two years old, the group with130-200 mm was three years old, and the group over 200 mm was four years old. The total length of sexually mature fishes was 65 mm for females and 70 mm for males. The sexually mature individuals grown in nature had a smaller total length than those reared in a laboratory. The spawning season was from May to late July, and the water temperature was 18.4-26.4℃ during the period. The prosperous spawning season was from May to June, and the water temperature was 18.4-21.8℃ during the period. The average number of eggs in the ovaries was 462 (151-919) per mature female, and the matured eggs were yellowish and spherical with a mean diameter of 2.31±0.33 (1.93-3.10) mm. Calculation length-weight relation of Korean aucha perch showed the constant a as 0.00002 and b as 3.01, condition factor (K) as 1.76 (1.01-2.63) on average, and the slope was a positive value of 0.0005.

• Korean Journal of Environment and Ecology
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• v.34 no.5
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• pp.402-412
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• 2020

This study aims to examine the population characteristics of the fish and the bluegill (Lepomis macrochirus), designated as ecologically disturbing fish, living in four water dams in the Ulsan area and to provide basic data. The survey of fish living in 4 water dams and surrounding tributaries in the Ulsan area from 2016 to 2017 found a total of 1,987 individuals of 28 species of 9 families and identified 6 Korea's endemic species is (21.4% indigenous rate), 4 exotic species, and 2 ecosystem disturbing species. Based on the number of fishes identified, the dominant species was Lepomis macrochirus, and the subdominant species was Hemiculter eigenmanni. The investigation of the age structure of the L. macrochirus found in the 4 water dams in the Ulsan area showed a large population of 1 to 2 old, and the population was growing fast. Moreover, the analysis of the total length-weight relationship and obesity of the L. macrochirus population showed that the regression coefficient b of the total length-weight relationship was greater than 3.0, and the habitat of the L. macrochirus population was in good condition. Obesity had a positive slope, and the growth state was relatively good. The result of this study can be used as useful data to predict the trend of the L. macrochirus fauna inhabiting in 4 water dams in the Ulsan area.