• Journal of Ecology and Environment
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• v.31 no.3
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• pp.233-241
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• 2008

Functional feeding groups (FFGs) of benthic macroinvertebrates are guilds of invertebrate taxa that obtain food in similar ways, regardless of their taxonomic affinities. They can represent a heterogeneous assemblage of benthic fauna and may indicate disturbances of their habitats. The proportion of different groups can change in response to disturbances that affect the food base of the system, thereby offering a means of assessing disruption of ecosystem functioning. In this study, we used benthic macroinvertebrate communities collected at 650 sites of 23 different water types in the province of Overijssel, The Netherlands. Physical and chemical environmental factors were measured at each sampling site. Each taxon was assigned to its corresponding FFG based on its food resources. A multilayer perceptron (MLP) using a backpropagation algorithm, a supervised artificial neural network, was applied to evaluate the influence of environmental variables to the FFGs of benthic macroinvertebrates through a sensitivity analysis. In the evaluation of input variables, the sensitivity analysis with partial derivatives demonstrates the relative importance of influential environmental variables on the FFG, showing that different variables influence the FFG in various ways. Collector-filterers and shredders were mainly influenced by $Ca^{2+}$ and width of the streams, and scrapers were influenced mostly with $Ca^{2+}$ and depth, and predators were by depth and pH. $Ca^{2+}$ and depth displayed relatively high influence on all four FFGs, while some variables such as pH, %gravel, %silt, and %bank affected specific groups. This approach can help to characterize community structure and to ecologically assess target ecosystems.

• Journal of Ecology and Environment
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• v.36 no.2
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• pp.125-129
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• 2013

The study on the major insect pests community of Hibiscus syriacus. There were three orders, seven families, and thirteen species of insects harmful to H. syriacus. When the harmful insects eating H. syriacus were classified according to which part of the flower they were eating, insects eating leaves, which considered of nine species four families and one order, accounted for 69.23 %. Insects sucking juice from leaves and stems comprised 15.38 %, with two species two families and two orders, while insects eating seeds comprised 15.38 %, with two species two families and two orders. Aphis gossypii appeared once per H. syriacus from the fourth week of April to the second week of June, appearing the most at a rate of 69.05 per H. syriacus during the first week of May. Dichocrocis surusalis appeared at a rate of 0.05 per H. syriacus during the third week of April and regularly appeared from the first week of July to the second week of September. Nortacha derogata appeared at a rate of 0.1 per tree during the first week of May, after which it continuously appeared until the third week of October. Anomis privata appeared at a rate of 0.05 per tree during the first week of May and continuously occurred from the fourth week of June to the fourth week of October. Its occurrence was most frequent at 2.30 per tree during the third week of September.

• Journal of Environmental Science International
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• v.24 no.2
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• pp.229-236
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• 2015

In this study, the fish-migration ratios of rivers were analyzed, with the aim of proposing objective materials to help South Koreans to establish fish migration systems efficiently in the future. A total of 34,012 weirs have been built in the five major basins, with 5,081 fish-ways observed. Consequently, the fish migration ratio was considered low (14.9 %). According to the findings of the study analyzing the 5,081 fish-ways, standard-type fish-ways took up 68 % of the total while the non-standard types accounted for 32 %. The five major basins were observed to have a total fish-migration ratio of 21.4 %. Regarding tributaries, Tributary 1 accounted for 27.5 % of the fish-migration ratio, while Tributary 2 and 3 accounted for 19.8 % and 16.3 %, respectively. In conclusion, the study argues that any relevant field in the fishing industry of South Korea needs to improve their understanding of the fish-migration ratio. This would be expected, eventually, to help them maximize the efficiency of a minimum number of fish-ways. In addition, the study supports the need for those in relevant fields to study carefully the ecological needs of each fish species, before establishing priority standards for the building of fish-ways.

• ALGAE
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• v.19 no.2
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• pp.107-114
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• 2004

Patterns of epilithic algal colonization on artificial substrata (unglazed ceramic tiles) were investigated from 23rd April to 3rd July 1999 at weekly intervals over a 10 weeks period outside and inside the mesocosm in Togyo reservoir within the Civilian Passage Restriction Line near Demilitarized Zone (DMZ) in Korea. The highest standing crops of epilithic algae was 1,798$\cdot$10³ cells$\cdot$$cm^{-2}$ outside the mesocosm on 26th June and also inside the mesocosm those was 2,391$\cdot$10³ cells$\cdot$$cm^{-2}$ on 26th June, 9 weeks after the experiment began. The dominants outside the mesocosm were Achnanthes minutissima, Navicula bicephala, Oscillatoria angusta, Synedra delicastissima, S. tenuissima, S. ulna v. danica and Tabellaria flocculosa, and those inside the mesocosm were Achnanthes minitissima, Coenochloris polycocca, Fragilaria crotonenesis, Peridinium cinctum, Synedra delicatissima, Tabellaria flocculosa and Ulothrix subtilissima. Diatoms were most abundant and Achnanthes minutissima was the most important species colonizing on the tiles. Chlorophyll-a content was highest value of 5.4 mg$\cdot$$m^{-2}$ on 19th June after 8 weeks growth outside the mesocosm and was 24.4 mg$\cdot$$m^{-2}$ on 26th June, 9 weeks after the experiment began on tiles inside the mesocosm. It was also shown that unglazed ceramic tiles were a more suitable substratum for colonization than the glass slides. Consequently the substratum selection plays an important role in the colonization by the epilithic algal community.

• Journal of Ecology and Environment
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• v.40 no.1
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• pp.75-83
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• 2016

Background: In order to evaluate the effect of pH, known as a critical factor for shaping the biogeographical microbial patterns in the studies by others, on the bacterial diversity, we selected two sites in a similar geographical location (site 1; north latitude 35.3, longitude 127.8, site 2; north latitude 35.2, longitude 129.2) and compared their soil bacterial diversity between them. The mountain soil at site 1 (Jiri National Park) represented naturally acidic but almost pollution free (pH 5.2) and that at site 2 was neutral but exposed to the pollutants due to the suburban location of a big city (pH 7.7). Methods: Metagenomic DNAs from soil bacteria were extracted and amplified by PCR with 27F/518R primers and pyrosequenced using Roche 454 GS FLX Titanium. Results: Bacterial phyla retrieved from the soil at site 1 were more diverse than those at site 2, and their bacterial compositions were quite different: Almost half of the phyla at site 1 were Proteobacteria (49 %), and the remaining phyla were attributed to 10 other phyla. By contrast, in the soil at site 2, four main phyla (Actinobacteria, Bacteroidetes, Proteobacteria, and Cyanobacteria) composed 94 %; the remainder was attributed to two other phyla. Furthermore, when bacterial composition was examined on the order level, only two Burkholderiales and Rhizobiales were found at both sites. So depending on pH, the bacterial community in soil at site 1 differed from that at site 2, and although the acidic soil of site 1 represented a non-optimal pH for bacterial growth, the bacterial diversity, evenness, and richness at this site were higher than those found in the neutral pH soil at site 2. Conclusions: These results and the indices regarding diversity, richness, and evenness examined in this study indicate that pH alone might not play a main role for bacterial diversity in soil.

• Ocean and Polar Research
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• v.29 no.3
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• pp.205-216
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• 2007

The purpose of this study was to investigate effects of large scale marine sand mining on the marine ecological community. For the study, four stations along the coast were selected and monitored in 1998 and 2001 at mining areas and non-mining areas about the Gyeonggi Bay. The result revealed that in 1998, 9 species of fishes, 16 species of crustaceans, and 6 species of mollusks were collected where as in 2001, 11 species of fishes, 5 species of crustaceans, and 2 species of mollusks were collected, uncovering the fact that fishes have diversified while crustaceans and mollusks have reduced on a grand scale. Also, there were two key characteristics regarding the changes of biological communities in mining and nonmining areas. The first was the dwindling of crustaceans inhabiting the sand area. This outcome may be accounted for by the facts that physical removal of seabed sediments and re-sediment due to expansion of floating particles cause direct influence on the ocean floor ecosystem and have continuous effect on the communities of crustaceans which feed on them. Secondly, the newly arrived species and their population during spring and summer seasons have increased in the non-mining areas and have decreased in the mining area. It can be concluded that highly nomadic fish species migrate toward areas with less disturbance or destruction of ecosystem from marine sand mining, and consequently, the communities of fishes change in the sea area. Setting aside the characteristics of the investigated sea areas where the arriving conditions of species vary by seasons, the clear differences of population of organisms in those areas are due to environmental alterations owing to the marine sand mining ; if those large-scale marine sand mining activities continue in the Gyeonggi Bay, their effects on biological communities in the areas will only grow.

• Journal of Korean Society of Rural Planning
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• v.13 no.3
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• pp.13-21
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• 2007

This study focus on the pilot case of a scenic landscape agriculture in Go-Chang county for the innovative rural development strategy related the green tourism in Korea. The Go-Chang county in Jeon-Buk province has been progressed the diversified agricultural crops production region. The Go-Chang county is known as the famous cultural tour place that has the many historical and cultural resources (provincial natural park, traditional music, great stone cluster area, military castle walls, good tasted eel food and wine). But, today, the circumstances of global agricultural free trading situations is rapidly proliferated, it invited the depression of the agricultural incomes in rural regions in Korea. So, the Go-Chang county seeks trying to alternative development methods. The new frontier like scenic landscape agriculture is the one of the innovative strategies in this processes. The Go-Chang county selects and supports the scenic landscape agriculture for the new income production policy in connection with the green tourism. This study finds out the important components of the success of a scenic landscape agriculture for the introduction to the new frontier of peen tourism in Go-Chang county. First the scenic landscape agriculture development must be related the 4 season-ecological cultivation methods connected well-being trends. Second, it will be increased the income level of rural people by the competitive the rural green products and diversified green tourism programs which produced by the efforts of the rural people. Third, the success of scenic landscape agriculture and place marketing of rural green tourism depend on the creative community leaders.

• Journal of Korean Society of Rural Planning
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• v.22 no.4
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• pp.159-169
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• 2016

In recent years, the population structure has been changed by the progresses of 6th-industrialization and transportation in farming areas. This study aims to suggest a regional development plan of farming areas in accordance with the demographic changes. Population structure indicators were derived from previous studies and literature review in order to identify the types of farming areas. Demographic indicators separated to depopulation and population growth in farming areas through a standardized scoring method. This research found that the division of economy is not only the most important division in any other regional development divisions but also necessary to develop new sources of non-farm income through traditional culture, natural environment. In the social division, it is necessary to secure the facilities for the formation of a sense of community to multicultural families and existing residents in farming areas. In the environmental division, it is desirable to improve the quality and satisfaction of life for residents such as the sidewalk and park that utilize ecological environment, culture, history for both depopulation and population region. In the physical division, there is a need for improvement of the facilities of basic living infrastructure service such as roads, water supply and sewerage systems. In the institution division, sustainable financial support of the central government policy for farming areas is crucial for the improvement of residential environment in the farming areas of depopulation and population region.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.4
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• pp.46-56
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• 2008

This study examined the natural restoration of vegetation through monitoring of the development of a vegetation community from 2006 through 2007 after a forest fire. Approximately 5,000 $m^2$ in a forest near Topyeon-ri, Kangnae-myeon, Chungcheongbuk-do with Japanese red pine (Pinus densiflora) forest and its floor vegetation had been completely burned by a fire in April 2005. This area and another nearby Japanese red pine forest were selected as the experiment site and the control site, respectively. Vegetation survey was conducted at the experiment site and the control site. A seed bank experiment was carried out in the greenhouse to examine underground vegetation. Effective microorganism(EM) was applied to the seed bank experiment to estimate its effects on the direction of ecological succession. According to the results, a total of 36 plant species including shrub and herbaceous species were discovered in the experiment site. Quercus serrata, Lespedeza cyrtobotrya, and Castanea crenata, Rubus crataegifolius, Oplismenus undulatifolius, and Carex lanceolata were among the most abundant species. Biomass in the experiment site reached 2.4 times biomass than those in the control site, indicating the productivities of shrub and herbaceous layers are better in the experiment site. According to the result of the soil seed bank experiment of the experiment site, a total of 182 plants of 14 species were recorded. In addition, a total of 13 plants of 2 species were found from soil seed bank of the experiment site applied by EM. If EM is applied to the burned site, it will control the budding of herbaceous plants, creating the gap between herbaceous plants. This loss of competition is expected to help the restoration of trees in the burned area.

• Ocean and Polar Research
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• v.26 no.2
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• pp.113-120
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• 2004

The abundance, biomass and distribution of phytoplankton, bacterioplankton and heterotrophic protists in the Bering Sea were investigated from July to August 1999. Chlorophyll a concentrations in the surface waters ranged from 0.16 to $3.79{\mu}g\;l^{-1}$ Nano-phytoplankton were found to constitute from 63 to 98% of the total phytoplankton biomass, and were clearly the dominant primary producers. The biomass of bacterioplankton in the surface layers varied from 1.46 to $20.2{\mu}g\;C\;l^{-1}$ and accounted for 30% of the total phytoplankton biomass. The biomass of bacterioplankton integrated over a depth of 0 to 100m averaged 65.4% of the total phytoplankton biomass. The surface biomass of heterotrophic protists ranged from 1.2 to $27.4{\mu}g\;C\;l^{-1}$, and was within the same order of magnitude as that of bacterioplankton. Of the total biomass of heterotrophic protists in the upper 100m of the water column, 65% was attributed to protists in the nano-size class. The results of this study suggest that bacteria and nano-protists are important components of the planktonic community in the Bering Sea during the summer season. The abundance of bacterioplankton and planktonic protists decreased from the western to northeastern and eastern regions of the Bering Sea. The abundance of these organisms also decreased with depth. The available evidence suggests that variation in the abundance and distribution of these organisms may be affected by water currents and vertical temperature variation in the Bering Sea.