• Korean journal of applied entomology
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• v.30 no.1
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• pp.65-79
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• 1991

In order to investigate the species composition and the colony density of ants in Mt. Namsan, Seoul, 39 quadrats were installed in 13 vegetations, 443 colonies of ants were collected from June, 1989 to October, 1990. As the result, 4 subfamilies, 23 genera, 28 species was confirmed. Among them, Cerapachys humicola $O_{GATA}$ is new to Korean fauna along with the subfamily Cerapachinae. For the species composition of ant communities in each vegetation, Robinia pseudoacacia vegetation(containing 3 subfamilies, 14 genera, 15 species-53.6% of all colonies collected in Mt. Namsan) and Quercus mongolica vegetation (3 subfamiles, 12 genera, 14 species -50%) showed relatively rich composition, while Platunus orientalis vegetation (3 subfamilies, 3 genera, 3 species) showed the simplest composition. Colony density was the highest in Prunus sargentii vegetation (7.875 colony /$m^2$) and the lowest in Platunus orientalis (1.000 colony/$m^2$). The relative density of Paratrechina flavipes proved to be the highest (RD = 0.422) and that of Cerapachys humicola $O_{GATA}$ Massor aciculatus was the lowest (RD = O. 002 respectively). In the analysis of the similarity of ant communities between each vegetation by S¢rensen's coefficient, Prunus sargentii was very similar to Sorbus alnifolia (0.745) and Pinus densiflora (0.736), but had the lowest similarity to Metasequoia glyptostoboides and Chamaecyparis pisifera vegetation (0.164 respectively). Dominance of ants in each vegetation analyzed by Simpson'formula was found to be high in Platunus orientalis ($\lambda$ = 0.393) and Sorbus alnifolia ($\lambda$ = 0.392) and the lowest in Metasequoia glyptostroboides vegetation($\lambda$= 0.067). The analysis of diversity by reverse Simpson's coefficient revealed that it was high in Metasequoia glyptostroboides ($d_s$ = 14.925), Pinus rigida ($d_s$ = 7.874) and was the lowest in Platunus orientalis vegetation ($d_s$ = 2.545). Evenness calculated by using d. and $d_{max}$(maximal diversity) was high in Metasequoia glyptostroboides ($E_s$ = 0.714) and Chamaecyparis pisifera vegetation ($E_s$ = 0.624). On the contrary, Quercus mongo/ica vegetation had the lowest value of evenness ($E_s$ = 0.182).

• Journal of Ecology and Environment
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• v.29 no.6
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• pp.593-602
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• 2006

Species composition, spatial distribution of major species, diameter and height classes distribution, and species diversity were .analyzed in the Korean red pine (Pinus densiflora, hereafter referred as pine) forest in the permanent quadrats, which were designed for Long Term Ecological Research (LTER). Collected data were compared with those from the other areas including urban center (Mt. Inwang and Hongneung) and boundary areas (Mts. Acha, Bukhan, Bulam, Cheonggye, Daemo, and Surak), and natural areas (Mts. Seolak, Songni, and Wolak) to clarify the ecological characteristics of pine forest on Mt. Nam. Species composition of pine forest on Mt. Nam showed a similarity with those of urban center but did a little and big differences with those on urban boundary and natural areas, respectively. Such differences that pine forest on Mt. Nam showed, were usually due to Styrax japonicus, Sorbus alnifolia, Oplismenus undulatifolius, Ailanthus altissima, Ageratina altissima and so on, which showed higher coverage there. Predicted from diameter and height classes distribution of tree species, pine forest on Mt. Nam showed a possibility to be replaced by a S. japonica. Considered that this replacer species is not only a sub-tree but also shade intolerant, such successional trend could be interpreted as a sort of retrogressive succession. Those on urban boundary and natural areas showed a difference by displaying probabilities to be maintained as themselves as an edaphic climax or succeeded to oak forests. Species diversity of pine forest on Mt. Nam was lower than those in urban boundary and natural areas due to excessive dominance of several species, which led to different species composition from the other areas. Plants, which produced the differences, were species that flourishes in the polluted industrial area (S. japonica and S. alnifolia), favors the disturbed site (O. undulatifolius), and exotic species (A. altissima and Eupatorium rugosum). Those results reflects that pine forest of Mt. Nam was exposed on severe environmental pollution and excessive human interferences.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.260-269
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• 2009

Hwabuk Dam has been under construction to reduce flood damage in Nakdong River watershed and to supply stable water for middle area of Gyeongbuk Province. Therefore, fish investigation in up and downstream of the dam was conducted from 2004 to 2008 in order to determine any negative effect on fish community due to dam construction and to use as fundamental data for conserving species diversity and maintaining stream health. According to data analysis on water quality, temperature, dissolved oxygen, pH, suspended solids, and total E-coli had seasonal variation, but they did not significantly differ in sites. However, biological and chemical oxygen demand, chlorophyll-a, nitrogen, and phosphorus representing organic matter and nutrient concentration were higher in upper site and decreased to lower site so that they differed by site. Concentration of arsenic among the heavy metals was less than 0.05 mg $L^{-1}$, which is regulated for protection of human health in water quality standard, except for 0.092 mg $L^{-1}$ in June 2005. During the study period, the total number of fish caught from the 6 sites was 10,263 representing 7 families 19 species. Among them, dominant and subdominant species were Korean chub (Zacco koreanus, 62.5%) and Chinese minnow (Rhynchocypris oxycephalus, 10.6%) which inhabit mostly in mid and upper streams, Korea. Among the 19 species, Korean endemic species were 9 species (47.4%) including Korean slender gudgeon (Squalidus gracilis majimae), Korean dark sleeper (Odontobutis platycephala), and Korean shiner (Coreoleuciscus splendidus). There was several individuals of the $1^{st}$-class endangered species, Naktong nose loach (Koreocobitis nahtongensis), caught in 2005${\sim}$2007, and no introduced species of fish was found in entire sampling period. According to result of community analysis, dominance index decreased toward lower site, but diversity and richness indices increased toward lower site. The equation of length-weight relationship on the dominant species was TW=0.000003$(TL)^{3.2603}$. The parameter b in the equation was greater than 3.0 indicating good nutritional condition in the populations. Compared to populations of Korean chub in other streams, the population in Hwabuk Dam watershed had higher mean of condition factor by size indicating better growth rate. With fish fauna and multi-metric health assessment model in each sampling attempt, index of biotic integrity (IBI) was evaluated and it resulted mostly in good (26${\sim}$35) and excellent (36${\sim}$40) condition in all sites, and the mean of IBI was the highest in site 5. The results indicate that it is very important to study not only environmental impact assessment with fish composition but also stream health assessment in order to conserve healthy aquatic ecosystem.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.515-524
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• 2019

The purpose of this study is to investigate the effects of artificial disturbance by analyzing and comparing the survey data of the Yeongju dam located in Yeongju-si, Gyeongbuk before and after impoundment. We surveyed four sites between the downstream of sediment control to the downstream of Yeongju Dam four times between April and October 2018. The macroinvertebrate data before the survey were gathered from the literature. The total number of benthic macroinvertebrates we observed was $35,037ind./m^2$, including 77 species, 48 families, 14 orders, 7 classes, and 3 phyla. The result of the community analysis showed that the dominant index increased from 0.44(${\pm}0.11$) before impoundment to 0.62(${\pm}0.16$) after impoundment. The diversity index increased from 2.26(${\pm}0.30$) to 1.75(${\pm}0.45$), the evenness index from 0.75(${\pm}0.10$) to 0.66(${\pm}0.14$), and the richness index from 3.11(${\pm}0.98$) to 2.25(${\pm}0.81$). The most dominant species changed from Hydropsychidae spp. to Chironomidae sp. The result of the Principal Components Analysis (PCA) based on Axis 1 showed that the sites of 2014 and Hydropsychidae spp. had a negative value, while the sites of 2018 and Chironomidae sp. had a positive value. In all study sites, the dominance increased while the diversity decreased. The community change was the largest in St. 2. The results of the functional group analysis showed that the scrapers increased while gathering-collectors increased among the functional feeding group and that the clingers decreased while borrows increased among the habitat oriented group. The Benthic Macroinvertebrate Streambed Index (BMSI) decreased from an average of 57.1(${\pm}8.0$, C class) to an average of 30.0(${\pm}12.1$, C class). St. 3 and St. 4, in particular, showed a high reduction rate.

• Korean Journal of Environment and Ecology
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• v.32 no.6
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• pp.603-617
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• 2018

This study surveyed the diversity and community characteristics of benthic macroinvertebrates and freshwater fish, which are the main animal classifications in a hydro ecosystem, from May to September 2017 in the western plains of the Demilitarized Zone (DMZ). The results showed a total of 125 species of benthic macroinvertebrates belonging to 66 families, 19 orders, and four phyla in the streams and wetlands. Among benthic macroinvertebrates, Coleoptera (27 spp.: 21.60%) was the largest group in terms of species richness followed by Odonata (26 spp.: 20.80%), non-Insecta (22 spp.: 17.60%), and Hemiptera (11 spp.: 8.80%) occupying in the lentic area. Of the feeding function groups (FFGs), predators (51 spp.: 56.67%) showed a relatively larger presence, indicating the dominance of hygrophilous invertebrates that usually inhabit the freshwater wetlands or ponds. Of the habitat oriented groups (HOGs), climbers (33 spp.: 24.44%) and burrowers (17 spp.: 12.59%) were the dominant groups. This observation is typical in a slow flowing habitat and can lead to the disturbance of the ecosystem due to cannibalism among predators. Cannibalism can be caused by stress induced by various population and environmental factors. For the ecosystem services benchmark (ESB) value, site 13 appeared to be the highest with 82 marks while other sites showed relatively lower rates and indices (III water quality class with ${\alpha}$-mesosaprobic). The analysis result of stability factors showed that almost all sites were evaluated to be the I characteristic group with high resilience and resistance or the III characteristic group that was sensitive to environmental disturbance and formed uneven and unstable communities. Of the freshwater fishes, 46 species (3,405 individuals) belonging to 39 families and 18 orders were identified in all the investigated sites. Among them, Cyprinidae (30 spp.: 65.2%) was the largest group, and Zacco koreanus was identified as the dominant species (728 individuals, 21.4%). The survey of freshwater fish communities found both stable communities (sites 7 and 13) with low dominant index (0.39) and high diversity index (2.29) and unstable communities (sites 2, 3, 8, and 10) in opposite tendency. This survey found five Korean endemic species, 17 species belonging to the export controlled species, two endangered species level II (Lethocerus deyrollei and Cybister chinensis), and rare species (Dytiscus marginalis czerskii) among benthic macroinvertebrates. The survey also found an invasive species, Ampullarius insularus, which was distributed throughout the whole area and thus can continuously disturb the ecosystem in the western plain area in the DMZ. Of freshwater fish, one natural monument (Hemibarbus mylodon) and three endangered species level II (Acheilognathus signifer, Gobiobotia macrocephalus, and G. brevibarba) were observed. The survey also found four introduced species (Pomacea canaliculate, Carassius cuvieri, Lepomis macrochirus, Micropterus salmoides) in the western DMZ area, indicating the need for the protection and conservation measures.

• Korean Journal of Environmental Biology
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• v.36 no.3
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• pp.400-411
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• 2018

This study was a survey of the Wonju stream in Wonju city from May 2015 to September 2016. A total of three sites were selected from the upstream area Gwanseol-dong to the downstream area Hojeo-myeon. Physicochemical analysis, aquatic insect changes, cluster analysis, functional group analysis, rarefaction curve, and statistical analysis were compared between 2004 and 2016. A total of 19 species (38.78%) in 2004 and 22 species (36.67%) in 2016 were analyzed, with the largest number belonging to ephemeroptera. The individual ratio ranged from 27,759.2 (ind. $m^{-2}$, 84.30%) in 2004 to 4,573.2 (ind. $m^{-2}$, 41.64%) in 2016, with the highest number involving diptera. As a result of the community analysis, significant differences were detected in the indices of dominance, diversity, evenness, and richness in 2004 and 2016 (p<0.05). Burrowers of the habitat orientation groups showed the greatest variation with an average of -68.00% (${\pm}2.15$) and the collector-gatherers of the functional feeding groups showed the highest variation of -40.12% (${\pm}1.77$). The rarefaction curve analysis suggested that the species was the poorest in the midstream regions in 2004 and 2016. Physical factors and water quality showed a significant correlation with diversity index, evenness index, and the number of individuals. MDS analysis of the similarity of upstream and downstream regions was high in 2004, and low in 2016. The differences were attributed to physicochemical changes such as increase in flow velocity due to improvement of small dams and changes in bottom structure.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.530-542
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• 2020

This study surveyed the central mountain area of Demilitarized Zone (DMZ) from March to October 2018 to reveal the appearance patterns of freshwater fish. We collected 7,744 individuals of 43 species in 12 families with skimming nets and cast nets in 12 stations during the survey. The dominant species was Zacco koreanus (30.3%), and the subdominant species was Z. platypus (18.5%), followed by Rhynchocypris oxycephalus (10.0%), R. steindachneri (6.7%), Microphysogobio yaluensis (5.9%), Acheilognathus signifer (4.5%), Pungtungia herzi (4.2%), and Orthrias nudus (2.6%). Among the collected species, four were legally protected. They included Hemibarbus mylodon, which was a natural monument, and Lethenteron reissneri, A. signifer, and Pseudopungtungia tenuicorpa, which were class II endangered wildlife designated by the Ministry of Environment. Twenty Korean endemic species (46.5%) and one exotic species, Micropterus salmoides, were also collected. Additionally, three climate-change sensitive species, R. kumgangensis, Ladislavia taczanowskii, and Cottus koreanus, and three landlocked species, L. reissneri, C. koreanus, and Rhinogobius brunneus appeared. The dominant species in each station were Z. koreanus (15 stations), Z. platypus (four stations), R. oxycephalus (four stations), and C. koreanus (one station). The species dominance index decreased from upstream to downstream (mainstream of Gimhwanamdae Stream), while the species diversity index and the species richness index increased. The community structure of the rivers was divided into the uppermost stream, upper stream, Han River, and Imjin River. Compared to antecedent surveys, this study collected the highest number of species. Two new species (Sarcocheilichthys variegatus wakiyae and Micropterus salmoides) were caught, while six species (Siniperca scherzeri, Leiocassis ussuriensis, Brachymystax lenok tsinlingensis, Rhodeus ocellatus, Abbottina springeri, Aphyocypris chinensis) did not appear. Gimhwanamdaecheon Stream has high biological value with the inhabitation of many species, including species under legal protection and high diversity and richness index scores. This paper also discussed a protection plan for this area.

• Korean Journal of Environment and Ecology
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• v.36 no.2
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• pp.150-164
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• 2022

The objective of this study is to analyze the biodiversity changes and characteristics of the benthic macroinvertebrate community in the Nakdong River with eight weirs, which was constructed as one of the Four Major River Restoration Projects from May to October 2020. The study also includes the analysis of changes in the major groups of benthic macroinvertebrates for about ten years, from 2010 to 2020. The surveys collected 97 species of benthic macroinvertebrates belonging to 83 genera, 52 families, 18 orders, five classes, three phyla, and 128.1 individuals/m². Chironomidae sp. and Tubificidae spp., which are pollutant indicators, dominated throughout the sections. The community analysis result shows the average dominant index and the diversity index of 0.62±0.20 and 1.87±0.63, respectively, and indicated the most stability of the freshwater ecosystem in the upper stream of the Nakdong River. The survey showed dominance by Chironomidae sp. at the center of the Nakdong River weir and the most unstable community in Chilgok and Gangjeong Goryeong weirs. The results of the community stability analysis showed a high distribution of the characteristic group I with high resilience and resistance and small distribution of characteristic group III with low resistance and resilience, indicating a very unstable condition of communities in the Nakdong River weir section. Predators were relatively abundant among the functional feeding groups (FFGs), whereas shredders, gathering-collectors, and filtering-collectors were relatively lower. Among the habitat orientation groups (HOGs), burrowers and climbers were dominant, indicating a wide distribution of groups in ecosystems with low dissolved oxygen. An endangered species level II of Macromia daimoji was found in Sangju and Nakdan weirs. The analysis results for 10 years from 2010 showed that the number of species and populations increased immediately after the dam construction but plummeted in 2016 and are now stabilizing. Chironomidae spp. has been dominant in all sections over the past 10 years, and they are currently maintained at a rate of about 50%. The EPT groups have decreased significantly since 2011, and the Plecoptera and Trichoptera of the group have not yet been restored. The population of Tubificidae spp. showed an increase after construction was completed in 2012 and drastically increased in 2015 and 2020. The species of Cristaria plicata, designated as endangered species level I, has not been observed since 2011 in Hapcheon Changnyeong weir. Moreover, Macromia daimoji was rarely observed in seven weirs until 2015, and it has been confirmed that the current distribution habitat has decreased rapidly.

• Korean Journal of Environment and Ecology
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• v.37 no.4
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• pp.259-272
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• 2023

This study set up 49 survey areas with an area of about 400 square meters in Abies koreana natural habitat to identify the species composition and vegetation structure of the A. koreana forest in the Mt. Jiri Nation Park, conducted field surveys using phytosociological methods, and performed the cluster analysis using the Two-Way Indicator Species Analysis (TWINSPAN) and Table manipulation. Subsequently, species composition analysis using the importance value, species diversity analysis, DBH analysis, sapling analysis, and similarity analysis was conducted by each cluster type. The cluster analysis classified the A. koreana forest in Mt. Jiri into five clusters, A, B, C, D, and E. The forest was divided into two clusters, Magnolia sieboldii-Dryopteris crassirhizoma-Sasa borealis and Betula ermanii-Solidago virgaurea-Calamagrostis arundinacea. The former was classified as type A and B by Cornus controversa-Hydrangea macrophylla, and the latter was classified as type E, a typical community, and a Sorbus commixta-Rhododendron mucronulatum cluster. And the S. commixta-R. mucronulatum cluster was divided into C type and D type by Picea jezoensis-Ligularia fischeri and Ainsliaea acerifolia. Through vegetation analysis, the importance value of A. koreana, Quercus mongolica, Acer pseudosieboldianum, Fraxinus sieboldiana, and B. ermanii was highly expressed in the A. koreana forest in Mt. Jiri. Regarding species diversity, the results were similar to those reported in other studies of A. koreana forests in Mt. Jiri. The analysis of diameter at breast height (DBH) showed that A. koreana dominated all layers, and the growth of saplings was also good, indicating that the dominance of A. koreana is expected to continue for a while. However, when considering the value of biodiversity that is expected to increase and threats caused by climate change, systematic preservation and management are required to respond to various threats based on continuous monitoring.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.3
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• pp.159-169
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• 2007

Excessive input of organic matters from fish cage farms to the coastal waters has been considered as one of the major factors disturbing their benthic ecosystem. Sediment samples were taken from around the two fish cage zones (A and B) in Tongyeong coast in June and August 2003, to evaluate the ecological impacts of fish cage farming activity on the macrobenthic polychaete communities. Polychaete accounted for $81{\sim}87%$ of the total macrofauna individuals from each of the sampling stations. The number of species, abundance, diversity and dominant species of polychaete were rapidly changed with the distance from the fish cages. Within 10 m from the fish cages, Capitella capitata, which is a bio-indicator for the highly enriched sediments, was a dominant species and the lowest diversity was recorded. In particular, the maximum density (${\sim}18,410\;ind.m^2$) of C. capitata was found at Farm A where fish cages were more densely established within a semi-enclosed bay system. The sampling zone between 10 m and 15 m showed a rapid decrease of C. capitata with a rapid increase of the numbers of species, implying that this zone may be an ecotone point from a highly to a slightly enriched area. In the sampling zone between 15 m and 60 m, a transitional zone, which represents slightly enriched condition before normal one, was observed with additional increase and maintenance of the number of species and density of polychaete. In addition, the potential bio-indicators of organic enrichment, such as Lumbrineris longifolia and Aphelochaeta monilaris were the predominant species in the sampling zone. Multidimensional scaling (MDS) ordination plots and k-dominance curves confirmed the above results on the gradual changes in the macrobenthic polychaete communities. Our findings suggest that the magnitude of impact of fish cage farming activity on polychaete communities is probably governed by a distance from fish cage, density of fish cage and geomorphological characteristics around fish cage farm.