• Korean Journal of Environment and Ecology
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• v.34 no.2
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• pp.142-156
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• 2020

This study surveyed Gyeongan Stream, a tributary of the Han River Drainage System, from April to October 2017 to investigate the characteristics of fish communities. The survey collected 40 species of 11 families from 48 survey stations using kick nets and cast nets. The dominant and subdominant species were Zacco platypus (48.0%) and Rhynchocypris oxycephalus (17.7%), respectively. The next most abundant species were Pungtungia herzi (6.8%), Z. koreanus (5.0%), Carassius auratus (4.3%), Squalidus gracilis majimae (2.7%), and Rhodeus notatus (2.5%). Among the fish collected, 14 species (35.0%) were Korean endemic species, and the exotic species were Micropterus salmoides, Lepomis macrochirus, and Cyprinus carpio (Israeli type). The land-locked species were Plecoglossus altivelis, Rhinogobius brunneus, and Cottus koreanus, while the species sensitive to climate change was C. koreanus. The community analysis showed that the dominance was higher at the uppermost stream station, whereas diversity and abundance tended to be lower at the upstream station and higher toward the downstream station. The community structure was largely divided into rivers (uppermost stream, upstream, and middle-lower stream) and lake. The river health was mostly good (23 stations, 47.9%) and fair (15 stations, 31.3%). Comparison with past surveys showed that 12 species identified in the past surveys did not appear in this survey; nine species appeared for the first time in this survey; and the ecosystem disturbance species - M. salmoides and L. macrochirus - tended to spread more widely gradually.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.236-242
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• 1987

The study was conducted to interprete the fluctuation of weed vegetation in plant-sociological impacts as affected by the mixture use of oxyfluorfen and glyphosate with various dosages. Also, intended to know the real interaction between two herbicides in weeding efficacies. The better efficacy from the above mixture was recognized than from the oxyfluorfen + paraquat mixture on the perennial-sites. In lower rate mixture of oxyfluorfen, the dominance index was increased by the annual grass species (ie. Digitaria), and of glyphosate by the biennial Stellaria and perennial species (ie. Artemisia). Also, the positive maximum action of both oxyfluorfen and glyphosate in various mixture rates was categorized upto 0.55kg ai/ha for oxyfluorfen and 0.35kg ai/ha for glyphosate, respectively. However, the interaction between the above two herbicides recognized actually as negative. Consequently, the use of mixture compound of oxyfluorfen with glyphosate are expected rather to promote the control efficacy of specific weed species, to enlarge the weeding spectrum and to prolong the weeding periods than to reduce the application rate of both chemicals depending on any synergic interactions.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.138-151
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• 2013

This study was carried out to investigate the distribution and habitat types of prickly lettuce, Lactuca scariola of Europe origin for supplying the basic data of management plan. It showed fairly nation-wide distribution although excessive growth was rather limited in the wild. Its habitat types were divided into four types like open fields, roadsides, seashores and riversides. Species diversity examined by species rank-dominance curve tended to increase over riverside > seashores > open fields > roadsides. As a result of analyzing life form, therophytes were more than 50%, means that the habitats of L. scariola were disturbed by human activities etc. Urbanization Index was analyzed 9.1% in roadsides, 7.4% in seashores, 5.8% in open fields and riversides. It has high spread potential with a large number of wind-flying seed per plant. It was evaluated that prickly lettuce was mainly spread along the newly constructed road, expressway and invaded the original ecosystem in the cultivated land as weeds. But it has played a role as a pioneer species in open fields. It is recommended to remove where it has considerable impact on the native plant species of conservation value.

• 한국해양학회지
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• v.24 no.4
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• pp.184-193
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• 1989

An investigation on the soft-bottom macrobenthic community in the inner Kyeonggi Bay was conducted in July, October of 1987 and February, May of 1988. The benthic fauna comprised a total of 87 species and showed mean density of 550 indiv./$m^2$. Major faunal groups are polychaetes, molluks, and crustaceans, corresponding to 64.7%, 17.4%, and 15.2% in total abundance respectively. The most abundant species was Tharyx sp. (10.9%), and followed by Mactra veneriformis (10.5%), Mediomastus sp. (8.6%), and Glycinde sp. (8.0%) etc.. The important species in the intertidal zone were Mactra veneriformis, Hinia festiva, and Nephtys californiensis, whereas those in subtidal channel region were Tharyx sp., mediomastus sp., Sternaspis scutata, and Nephtys polybranchia. The study area could be divided into 4 station groups based on the species composition; two groups within interidal flat and two in channel regions. Each station group sustained its specific benthic faunal assemblage; Mactra-Hinia, Aricidea-Haploscoloplos assemblages in the intertidal flat and Harpiniopsis-Urothoe, Mediomastus-Sternaspis assemblages in the subtidal channel region. The Mediomastus-Sternaspis assemblage showed the highest species number and population density, and also did the highest diversity and evenness indices. The Harpiniopsis-Urothoe assemblage showed the poor species composition and abundance, and so recorded the highest dominance index. Two assemblages in the intertidal flat had the intermediate values in all the biological parameters. The northern channel region of zone S-2 showed the high abundance in species composition, which seems to be caused by the heterogeneous sediment and the organic enrichment from the Han River and the Incheon industrial complex.

• Journal of agriculture & life science
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• v.46 no.4
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• pp.57-68
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• 2012

This study was conducted to provide basic data for the effective conservation and management in the black pine(Pinus thunbergii) stand which is located in the eastern coast of Gyeongsangbuk-do where the fragmentation of vegetation has been caused by the exploitation and the increase of tourists, and installed the seventy study sites($20{\times}20m$) in the dominant black pine stand. The black pine stand was classified into three groups(P. thunbergii - P. densiflora community, P. thunbergii - Robinia pseudoacacia community, P. thunbergii - P. densiflora-Celtis sinensis community) by a cluster analysis. As a result of Multi-Response Permutation Procedures test, there is significance among the communities. Pinus densiflora, Callicarpa japonica, Juniperus rigida, Rhododendron yedoense for. poukhanense etc. nineteen species were significant by indicator species analysis. The population structure of black pine stand showed that the class of diameter 12 to 26 cm was dominance, which had the inverse hump-shape pattern. Species diversity index(H') of investigated ranged from $1.033{\pm}0.234$ to $1.629{\pm}0.226$ in the woody layer group and from $2.448{\pm}0.457$ to $2.545{\pm}0.318$ $2.174{\pm}0.333$ in the herb layer group.

• Journal of Korean Society of Forest Science
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• v.107 no.4
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• pp.378-384
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• 2018

Chinese jujube (Ziziphus jujuba Mill.), a member of family Rhamnaceae, is an economically important species. It has high nutritional value in fruits, and its medicinal properties have led to extensive use in traditional oriental medicine. In this study, we investigated the genetic characteristics of 270 jujube germplasms collected from the six major jujube fruit production areas in Korea including Boeun and Gyeongsan, in order to understand the current situation on cultivated varieties of domestic jujube and to obtain useful data for selection of superior germplasms and establishing their breeding plans. The results of ISSR marker analysis revealed that the Shannon's information index of the 270 germplasms was 0.107 and the genetic similarity was as high as 0.935 showing the dominance of a specific cultivar or germplasm, and almost 67% (180) of them were identified at the same genotype with 'Bokjo'. The domestic commercial jujube populations could be characterized by very low genetic diversity and thus may be vulnerable to external disturbances. In addition, it seems that most of the jujube fruits in domestic market were largely produced through parthenocarpy.

• 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).

• Korean Journal of Environment and Ecology
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• v.25 no.2
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• pp.156-165
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• 2011

It is selected seven sites for marine algal flora and community structure and investigated seasonally from December 2008 to November 2009 in Gogunsan Islands, the west coast of Korea. A total of 58 species including 10 green, 16 brown and 32 red algae were collected and identified. Among these species, 11 species were found throughout the year. Annual mean biomass in dry weight were 213.8 g $m^{-2}$ at Sinsido 1, 143.1 g $m^{-2}$ at Sinsido 2, 133.3 g $m^{-2}$ at Sinsido 3, 164.0 g $m^{-2}$ at Munyeodo, 116.9 g $m^{-2}$ at Seonyudo, and 145.1 g $m^{-2}$ at Jangjado. Maximum biomass was recorded in Sinsido 1, and minimum mean biomass was Sinsido 4. The dominant species based on biomass were Sargassum thunbergii, Ulva pertusa, Sargassum fusiforme and Corallina pilulifera. S. thunbergii was the representative alga occurred at all seasons. The flora investigated could be classified into six functional groups such as coarsely branched form (46.6%), filamentous form (27.6%), sheet form (17.2%), thick leathery form (3.4%), jointed calcareous form (3.4%) and crustose form (1.7%). The R/P, C/P and (R+C)/P value reflecting flora characteristics were 0.33~0.75, 1.11~2.50, 1.47~3.25, respectively. Diversity index (H') and dominance index (DI) indicated that stability of seaweed community of Gogunsan Islands was unstable and environmental conditions were bad. According to multidimensional scaling (MDS) and cluster analysis, Gogunsan Islands were divided into three distinct groups. The first group was Sinsido 2, Sinsido 3, Seonyudo and Muyeodo and the second group comprised Sinsido 1 and Jangjado and the other was Sinsido 4 due to meaningful difference in similarity.

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.356-367
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• 2012

Community structure of fish and inhabiting status of endangered species, Cobitis choii and Gobiobotia naktongensis were investigated in the Ji Stream, a tributary of the Geum River Drainage System of Korea from May to October 2011. Ten to 23 fish species inhabited upper stream (St. 1~St. 4) with a Aa-Bb river type composed of mostly pebble and cobble bottoms, 16~28 species did middle stream (St. 5~St. 7) with a Bb type composed of mostly cobble and boulder bottoms, and 20-29 species did lower stream (St. 8~St. 10) with a Bb-Bc type composed of mostly sand bottoms. A total of 44 species belonging to nine families were found in the stream during the survay. The dominant species were in the order of Zacco platypus (37.2%), Pungtungia herzi (5.8%) and Pseudogobio esocinus (5.5%). Other abundant species included Acheilognathus lanceolatus (5.3%), Zacco koreanus (5.2%), Hemibarbus longirostris (4.9%) and Squalidus gracilis majimae (3.5%). Among residing species, 16 species were endemic to Korea, two (Cobits choii and Gobiobotia naktongensis) were endangered, and one (Micropterus salmoides) was non-indigenous. The similarity index based on species composition and abundance clearly delineated the fish community of the Ji Stream according to the three major sections, which were defined at the above. Dominance index gradually decreased toward downstream, while diversity, evenness and species richness indexes gradually increased toward downstream. The two endangered species, C. choii and G. naktongensis co-occurred at the lower stream due to the prevalence of a sandy substratum.

• Journal of Environmental Impact Assessment
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• v.26 no.1
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• pp.27-43
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• 2017

The objectives of the study were to evaluate fish compositions, endangered species, community structure, physical habitat, and general water quality for a preliminary environmental impact assessment of Jeokbyeok River on the road construction between two regions. Total number of species and total number of individuals, based on CPUE, were 23 and 1186, respectively. The endangered species (I, II) as the legal protection species were Pseudopungtungia nigra (79 samples) Gobiobotia brevibarba) (5) Gobiobotia macrocephala (2), indicating a requiring of endangered species conservation. In the meantime, exotic species and ecological disturbing species such as Micropterus salmoides and Lepomis macrochirus, were not present, indicating a well conserved area. According to fish community analysis, values of species diversity index were high (range: 0.788 - 1.030), and the dominance index were low (range: 0.097 - 0.183), indicating that the fish community in this area was maintained well without high dominacne by specific species. Also, fish analysis on tolerance guilds and trophic guilds showed that the proportions of sensitive species were largely exceeded the proportions of the tolerant species, while the proportions of insectivore species were largely exceeded the proportions of the omnivore species. This outcome suggests that the ecosystem was well maintained in terms of tolerance and trophic compositions (food chain). Ecological health, based on the multi-metric fish model of Fish Assessment Integrity (FAI), reflected those fish conditions. In other words, values of FAI model averaged 82.4, which means a "good condition" in the criteria of ecological health by the Minstry of Environment, Korea. In addition, general water quality and physical habitat analyses showed that the system was in good condition. Under these conditions, if the road constructions between the two regions happen in the future, inorganic suspended solids may increase in the waterbody, and this may result in indirect or direct influences on the physical habitats and food chain as well as fish compositions, so the ecological protections and prevention strategy from the soil erosion are required in the system.