• Journal of Wetlands Research
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• v.5 no.2
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• pp.33-42
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• 2003

Habitat pattern and distribution of the water birds were analyzed along the Hyungsan River on nine sites during fifteen months from January 2001 to March 2002. Water birds including 16,186 individuals and 86 species in total were observed from all the surveyed sites at the downstream of the Hyungsan river. Site 5, which has been observed 4,669 individuals and 60 species of the birds, was the most favorite habitat for the water birds in the Hyungsan River. And the diversity of water birds from the Hyungsan river showed the fewest species and individual numbers of the water birds at the site 2 located at the estuary of the river and site 3, the small reservoir for filtering of the draining water from the industrial area. The similarity between habitats in the Hyungsan river was divided of three groups by the cluster analysis with the bird species and individual numbers such as coastal area, estuary sites, and rice paddy field areas.

• Korean Journal of Radiology
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• v.24 no.3
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• pp.235-246
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• 2023

Objective: It is difficult to predict the treatment response of tissue after stereotactic radiosurgery (SRS) because radiation necrosis (RN) and tumor recurrence can coexist. Our study aimed to predict tumor recurrence, including the recurrence site, after SRS of brain metastasis by performing a longitudinal tumor habitat analysis. Materials and Methods: Two consecutive multiparametric MRI examinations were performed for 83 adults (mean age, 59.0 years; range, 27-82 years; 44 male and 39 female) with 103 SRS-treated brain metastases. Tumor habitats based on contrast-enhanced T1- and T2-weighted images (structural habitats) and those based on the apparent diffusion coefficient (ADC) and cerebral blood volume (CBV) images (physiological habitats) were defined using k-means voxel-wise clustering. The reference standard was based on the pathology or Response Assessment in Neuro-Oncologycriteria for brain metastases (RANO-BM). The association between parameters of single-time or longitudinal tumor habitat and the time to recurrence and the site of recurrence were evaluated using the Cox proportional hazards regression analysis and Dice similarity coefficient, respectively. Results: The mean interval between the two MRI examinations was 99 days. The longitudinal analysis showed that an increase in the hypovascular cellular habitat (low ADC and low CBV) was associated with the risk of recurrence (hazard ratio [HR], 2.68; 95% confidence interval [CI], 1.46-4.91; P = 0.001). During the single-time analysis, a solid low-enhancing habitat (low T2 and low contrast-enhanced T1 signal) was associated with the risk of recurrence (HR, 1.54; 95% CI, 1.01-2.35; P = 0.045). A hypovascular cellular habitat was indicative of the future recurrence site (Dice similarity coefficient = 0.423). Conclusion: After SRS of brain metastases, an increased hypovascular cellular habitat observed using a longitudinal MRI analysis was associated with the risk of recurrence (i.e., treatment resistance) and was indicative of recurrence site. A tumor habitat analysis may help guide future treatments for patients with brain metastases.

• Journal of Environmental Science International
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• v.28 no.11
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• pp.917-925
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• 2019

All of the animals and the plants in ecosystem are intimately connected to one another and the changes of forests and surroundings affect directly wild animals. This study was conducted at Hangyeong-myeon Cheongsu-ri located in the western part of Jeju Island belonging to Hangyeong Andeok Gotjawal Zone and Jocheon-eup Seonheul-ri located in the eastern part of Jeju Island belonging to Jocheon Hamdeok Gotjawal Zone. The survey on advent of birds was carried out twice a month from January 2014 to December 2015. We divided habitat environments into three survey sites such as a forest, a shrub forest and a farmland. A total of 65 species and 4,802 individuals were observed during the survey period. In a forest, 36 species and 1,287 individuals were observed while A shrub forest had 40 species and 1,554 individuals. And in a farmland, 41 species and 1,961 individuals were observed. The only 10 species were observed in forest and the only 7 species in shrub forest and the only 10 species in farmland. The species diversity and the evenness of a farmland were the highest, and the species richness was the highest in a shrub forest, and the dominance of a forest was the highest among the three areas. The similarity index between a shurb forest and a farmland was high while that between a forest and a farmland was low. The similarity index related with breeding appeared that a forest and a farmland was different from each other.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3B
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• pp.311-317
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• 2009

Similarity indices between sampling sites are calculated and cluster analysis of fish community is carried out by UPGMA based on investigating fish fauna and water environment. The restoration indicators as target species of Wonju stream are selected Cottus poecilopus, Zacco temmincki, and Zacco platypus along upper, middle, and lower streams, respectively. For better habitat suitability, low flow increasing and induced water quality improving must be secured by sewer system rearrangement and watershed management. Composite habitat suitability of Zacco temmincki as target species at middle stream of Wonju stream improve significantly by low flow increasing, which is very important factor to improve habitat suitability. The changes of hydraulics of depth and velocity govern the habitat suitability in general, but the effects are not significant. Low flow increasing with the change of 10% reducing of lower channel improves the composite habitat suitability of 0.37~0.78 to their origin of 0.1~0.25, which represent the channel restoration scheme of Wonju stream for enhancing the habitat suitability of fish community.

• Journal of Ecology and Environment
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• v.47 no.4
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• pp.250-260
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• 2023

Background: Crabgrass (Digitaria ciliaris, Poaceae) is a globally distributed weed, including in Afro-Eurasia, America, and Australia. As a highly gregarious plant, crabgrass is an important habitat for a diverse array of insects, and a potential habitat for agricultural pests. To compare the insect communities associated with the crabgrass community, insects were sampled using sweep sampling (100 sweeps per sample) at five sites, including Daejeon (Daejeon and Gap rivers), Anseong, Namhae, and Inje, with a focus on the Daejeon River. Results: A total of 5,888 individual insects belonging to eight orders, 42 families, and 115 species were collected from the five sites. Both the number of species and individuals of Hemiptera were the highest at all of the sites. In the present study, 73% of the insect population fed on D. ciliaris as a host plant. The dominant species in the D. ciliaris community was Laodelphax striatellus (Delphacidae), being ubiquitous at all the sites which showed a high abundance of rice pests in the communities and the suitability of D. ciliaris as an alternative host plant for them. The Shannon-Wiener diversity index was highest in Inje on 17 September (2.88), and the Chao1-bc diversity index was highest in the Gap River on 5 September (80). The sampling efficiency of 100 sweep samples (sample coverage) was calculated to be as high as 90%. The results of the samples taken from September to November in the Daejeon River showed that the number of species and individuals decreased gradually over time, and the number of dominant species decreased sharply between September and October. Similarity analysis indicated that sampling dates that were closer together yielded sampled assemblages with higher faunal similarity. In addition, in each sampling, the difference in the minimum temperature during the two-week period prior to sampling and faunal similarities were negatively correlated. Conclusions: This study provides foundational data that could enhance our understanding of insect diversity in D. ciliaris. The data can facilitate ecological conservation and management of Korean grasslands generally, as well as identification of potential pests that may disperse from D. ciliaris communities to nearby farmland.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.714-723
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• 2020

This study was conducted to investigate the community stability and similarity of benthic macroinvertebrates in the Giran stream between August and September 2018, and compare results to those reported by Lee (2004). As relates to the total number of species in each taxon in 2018, 45 species were additionally discovered compared to the 2003 study; the number of EPT taxa increased by 14 species and OCH taxa increased by 18 species. The diversity and richness indexes increased while the dominance index tended to decrease. According to analysis of functional feeding groups, 11 more Gathering-collector species were found, making it the highest functional feeding group with 24 species. According to analysis of functional habitat groups, 15 more clinger species were found than in the past, making it the highest functional habitat group with 41 species. A community stability comparison showed that species belonging to 'Stability Group I' had the highest stability rate at 57.1% in 2003 and 61.5% in 2018. According to the biological water quality assessment, in 2018, the average water quality level at each survey site was 'Ia' and 'Very Good' in terms of environmental conditions. As a result of the similarity analysis between the survey points for the species that appeared, two large groups of similarities were classified (similarity group 1: 2003 sites, similarity group 2: 2018 sites).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.3
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• pp.29-42
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• 2023

As the destruction of habitats due to recent development continues, there is also increasing interest in endangered species. Mankyua chejuense is a vulnerable species that is sensitive to changes in population and habitat, and it has recently been upgraded from Endangered Species II to Endangered Species I, requiring significant management efforts. So in this study, we analyzed the potential habitats of Mankyua chejuense using MaxEnt(Maximum Entropy) modeling. We developed three models: one that considered only environmental characteristics, one that considered artificial factors, and one that reflected the habitat of dominant tree species in the overstory. Based on previous studies, we incorporated environmental and human influence factors for the habitats of Mankyua chejuense into spatial information, and we also used the habitat distribution models of dominant tree species, including Ulmus parvifolia, Maclura tricuspidata, and Ligustrum obtusifolium, that have been previously identified as major overstory species of Mankyua chejuense. Our analysis revealed that rock exposure, elevation, slope, forest type, building density, and soil type were the main factors determining the potential habitat of Mankyua chejuense. Differences among the three models were observed in the edges of the habitats due to human influence factors, and results varied depending on the similarity of the habitats of Mankyua chejuense and the dominant tree species in the overstory. The potential habitats of Mankyua chejuense presented in this study include areas where the species could potentially inhabit in addition to existing habitats. Therefore, these results can be used for the conservation and management planning of Mankyua chejuense.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.691-709
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• 2011

This study was performed to classify habitat types depending on environmental factors and to find out distribution characteristics of functional feeding groups of aquatic insects which were collected at that habitat types. Field survey was conducted twice in a year for every spring and fall from 2007 to 2008 for 38 sites in the Geum River. During the field survey 15 environmental factors were measured at each 38 sites and analyzed by similarity analysis method to classify habitat types. The result of similarity analysis showed that the 38 sites could be grouped into 7 classes like as C1 and C3 class belong to Head water(HD), C2 and C4 and C5 class belong to Middle stream(MS), C6 and C7 class belong to Large River(LR) based on euclidean distances 4. And also, we could extract the main environmental factors affecting the classification of habitat types such as Stream Width and Elevation of physical environmental factors, Water Temperature, Conductivity and DO of chemical environmental factors, percentages of Sand, Silt and Gravel of substrate factors. Total 142 species of aquatic insects in 46 families, 9 orders were collected during the field surveys and the occurrence number of species and individuals showed high correlation with the Velocity factor and the percentage of Sand factor of each habitat types. In addition, correlation analysis between functional feeding groups and environmental factors represented that (1) Filtering-collectors(FC) affected by Velocity, Stream Width and Silt, (2) Gathering-collector(GC) affected by Velocity, (3) Predator(P) affected by Elevation, Velocity, Boulder, Conductivity and Sand, (4) Plant-piecer(PP) affected by Water Width and Silt, (5) Scraper(SC) affected by Elevation and Conductivity, (6) Shredder(SH) affected by Elevation, Boulder, DO, pH, Conductivity and Water Temperature respectively. As a result of this study, Elevation, Stream Width, Velocity, Conductivity, Water Temperature and percentage of Sand factors which were deduced by stepwise multiple regression analysis had correlations($r{\geqq}0.600$, p<0.01) with biota community inhabitation. Therefore these six environmental factors were regarded as major environmental factors that might affect highly the distribution of functional feeding groups in stream ecosystem of the Geum River.

• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.506-512
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• 1996

Community structure and soil properties of larch forest which are used for breeding site by herons were studied at Apgogri, Hoengsung, Kangwon Province. This site has been protected as a Natural Monument(No. 248) from 1973, in Korea. Herons have used this habitat from February to October every year. In 1995, more than 700 herons were observed in this habitat. Most of the larches died due to group breeding of herons, and no larch saplings were found at forest floor. Nutrient contents of soil in this habitat were much higher than those in control plot(non-breeding site). This must be due to the addition of faeces from herons and of thin twigs and other organic materials from the canopy and bird nests. Species composition of herb layer in this habitat was quite different from that in control plot. Breeding site was dominated by Humulus japonicus, Persicaria fauriei, Persicaria perfoliata, Commelina communis, Chelidonium majus var. asiaticum, Digitaria sanguinalis, Bidens bipinnata. Dioscorea batatas which are indicator species of soil eutrophication. Similarity index of shrub and herb layer between the breeding site and control site was 0.36 and 0.07, respectively.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.2 s.109
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• pp.16-31
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• 2005

This study was carried out to design a bridge-type ecological corridor plan in a forested neighborhood park affected by road construction in Dongjak-gu, Seoul. In order to study the site conditions, we analyzed topography, ecosystem structure, and user behavior and trail use. Existing vegetation was classified into 12 types. Based on a vegetation analysis, the Populus albaglandulosa and Robinia pseudoacacia communities, where planted species are dominant, were distributed extensively in the southern forest area. Planted areas with a single-layer structure of Korean landscape woody plants and Robinia pseudoacacia communities with a single-layer structure were distributed extensively in the northern forest and water-supply area. Based on a study of 28 quadrats, the similarity index between the multi-layer plant communities distributed in the southern forest and the single-layer planted areas was low. Twenty-four species of wild birds(355 individuals) were found in the survey area, including nine interior species and three urban species. The study of user behavior and numbers showed most users were walkers and few users were observed in the southern forest while most users were observed in the northern forest and water supply area. We selected some wild birds as model species to represent migrating species believed to use this park as an ecological corridor during migration. We suggested the new park plan include the following: improvement of vegetation structure for wildbird migration and habitat, connection of park trails for users and presentation of a landscape linked to nature.