• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.317-330
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• 2009

To diminish the levels of organic matters, a novel S-CROM (continuous removal of organic matters in the stream system using freshwater bivalve), was developed and applied to the polluted stream discharging from the wastewater treatment plant, Pocheon stream, Pocheon city (Korea). Major pollutants of the stream were human population and industrial wastewaters. The study was conducted at a small dam constructed within the stream, often called 'bo', and designed with four tanks; no mussels and no sediment (negative control), no mussels and sediment (positive control), 30 mussels and sediment (D1), and 60 mussels and sediment (D2). Physicochemical and biological parameters were measured at 12 hours interval (day and night) after mussel stocking. Results indicated that Anodonta woodiana Lea (D2) clearly removed approximately 72% of chl-$\alpha$ and 57% of suspended solids on second day, however, there were no differences in removal activities between animal densities (P>0.5). Dislike a laboratory CROM system, which previously developed, there were no huge release of nutrient ($NH_3$-N and SRP), due perhaps to the higher flow rate and the lower animal density. Therefore, we may suggest that if we can determine the relevant current and the animal density considering the stream state, an S-CROM system has a strong potential to water quality improvement of eutrophic streams. Some characteristics on both CROM and S-CROM were compared.

• Korean Journal of Ecology and Environment
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• v.51 no.3
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• pp.234-244
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• 2018

The roadkill that animals die after bumping by vehicles on the roads is acting as a factor to decrease the size of various animal populations. It has also been known to be the biggest artificial causations of Vertebrata deaths not only in urban areas but also protected areas such as national parks. Nevertheless, in the national park areas which are major protected national areas for conservation of national biodiversity and ecological diversity, snake roadkills occur frequently. Up to date, related studies are rare. Therefore, in this study, we described snake roadkill patterns on the roads in six national parks between 2006 and 2015. We identified total 736 snake roadkills compromising 10 different species. Five species, Rhabdophis lateralis, Elaphe dione, Gloydius ussuriensis, Lycodon rufozonatus, Gloydius brevicaudus occupied more than 91.7% of total roadkill cases. Active forager snakes were killed by roadkills more than ambush foragers, and the snake roadkill frequency was the highest in September, a migration period and in August when the young individuals dispersed at between 100 and 799 m altitude areas. Roads where roadkills were frequent lie between forest and hydrosphere or between forest and crop field road sides. Our results could be used to identify the trend of snake roadkills on the roads in national parks, and to establish effective roadkill mitigation measures and policies.

• Journal of Conservation Science
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• v.36 no.5
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• pp.333-338
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• 2020

Dye markers are used in the study of subterranean termites to determine colony territories and population sizes. Dyes not only allow the study of termite biology, but can also be used for control purposes. Although Reticulitermes speratus kyushuensis causes damage to wooden historical properties in Korea, the dye markers have not been applied. Therefore, we evaluated the applicability of Nile Blue A dye for R. s. kyushuensis. Filter papers dyed with concentrations of 0.05%, 0.10%, and 0.25% (w/w) were each fed to termite populations through a no-choice feeding test for 1, 3, or 7 days. After 4 weeks, the survival rate, dyeing rate, and maintenance of dyeing were recorded. The results showed high survival rates with lower dye concentrations and shorter feeding periods. Among the combinations of concentrations and days, high survival rates, dyeing rates, and dyeing maintenance periods were found at concentrations of 0.05% and 0.10% for 3 days of feeding. These maximized the survivorship and visibility. The results from the current study can be applied to investigate the ecology and control of R. s. kyushuensis in both the laboratory and field.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.116-125
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• 2017

Alpine plants with a scarcity of pollinators in harsh environments have been believed to undergo selfing for reproductive assurance; however, contradictory evidence is also available. Snowmelt regimes in alpine areas function to change life history characteristics of alpine plants such as flowering time and duration; yet the effects of snowmelt regimes have never been tested in alpine plants in Korea. This study was conducted to investigate the dichogamy, mating systems, and flowering characteristics of Megaleranthis saniculifolia populations [early and late snowmelt plots (ESP and LSP, respectively)] in a subalpine area of Sobaeksan Mountain in Korea. M. saniculifolia exhibited incomplete protogyny in that despite early maturation of pistils, maturation times of pistils and stamens within flowers were partly overlapped. Control and hand-outcrossing treatments produced significantly higher number of follicles and seeds per flower than autonomous and hand-selfing treatments. Based on the aggregate fruit set, the auto-fertility index (AI) and self-compatibility index (SI) were 0.33 and 0.50, respectively. Snowmelt occurred 10 days earlier in ESP than in LSP, thereby ESP and LSP showed distinct differences with regard to flower longevity and season, but showing no difference in peak flowering dates. We concluded that M. saniculifolia is an incomplete protogynous and largely outcrossing plant requiring pollinator service. Temporal variation in snowmelt time and subsequent changes in flowering characteristics under climate change may further threaten the population persistence of M. saniculifolia which has already been designated as endangered species in Korea.

• Korean Journal of Ecology and Environment
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• v.37 no.2 s.107
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• pp.227-235
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• 2004

Fish fauna and community structure were surveyed in the Nakdong River, Gumi City, Kyeongpook province from April 2001 to July 2002. During the surveyed Period, 39 species, 32 genera belonging to 10 families were collected. Cyprinid fish occupied 64.1% (25 species) and cobitid fish had 7.7% (3 species). Fourteen species(35.9%) of observed species were known as endemic species. The exotic fish was Micropterus salmoides (2.5%) . The dominant species were Zacco platypus (relative abundance: 36.7%) and Opsariichthys uncirorstris amurensis (22.7%). Carassius aurafus and Microphysogobio rapidus were numerous (4.0${\sim}$4.3%). The rare species comprising less than 0.15% were Acheilognathus koreensis, Aphyocypris chinensis, Iksookimia longicorpus, Coreoleuciscus splendidus, Rhinogobius giurinus, Sarcocheilichthys variagatus wakiyae, Silurus asotus astus, and Channa argus. It was found that the population density of carnivorous Opsariichthys uncirostris amurensis increased drastically in the mid-reach of the Nakdong river since it had been introduced from the other native rivers in the middle 1990s. Gobiobotia nakdongensis inhabit riffle (water velocity : 0.43${\sim}$0.67 m $s^{-1}$) of which the river bed is mainly sand. This species is considered to be in need of conservation. As the result of analyzing fish community in the surveyed area, the species diversity, evenness and dominant indices were 1.008, 0.663 and 0.196 respectively. The findings showed that the tributary, which the waterside plants were abundant and had various habitats, had a higher species diversity (1.112) than the main river (0.787). Sand mining had been disturbing the river ecosystem of the study stations 3, 11, 13 & 14, and these stations showed a quite low species diversity (0.421 ${\sim}$0.574).

• Korean Journal of Ecology and Environment
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• v.48 no.1
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• pp.68-76
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• 2015

There is no willow riparian vegetation in Jeju Island, Korea. Instead, a genetically-isolated population of Adina rubella is found in some parts of the riparian system. We describe its syntaxonomy and synecology. A total of 27 phytosociological relev$\acute{e}$s were collected, 11 relev$\acute{e}$s from 91 sites and 16 relev$\acute{e}$s from the previously published relevant materials. Data were analyzed by traditional Braun-Blanquet method and multivariate PCoA (Principal coordinates analysis). New syntaxa are distinguished, Adinion rubellae all. nov. and its type association Tripogono-Adinetum rubellae ass. nov. with two subassociations, typicum and rhododendretosum poukhanensae. Adino-Rhododendretum poukhanensae Itow et al. 1993 was discarded owing to mismatch of syntaxonomy and syngeography of Adina and Rhododendron phytocoena. The alliance Adinion is Jeju's regional and partly ombrotrophic vegetation occurring in pothole and rock crevice where are independent on ground-water table. We also suggest a revised alliance, Rhododendrion poukhanensae Lee 2004 ex. hoc loco in Korean peninsula, as a corresponding syntaxon to Adinion, which completely differs from Phragmito-Salicion. Finally we pointed out that Adina phytocoena requiring an absolutely monitoring has been threatened by river maintenance project of local government.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.226-238
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• 2011

Ichthyological fauna and community structure were surveyed in the Naeseong Stream around the planed Yeongju Dam, Yeongju City, Gyeongsangbuk-do from April 2007 to October 2009, During the survey period, 27 species (25 genera, 10 families) were collected. Cyprinid fish comprised 63.0% (17 species) and cobitid fish comprised 7.4% (2 species). Ten of the 27 species (37.0%) were endemic species. The dominant and subdominant species based on the number of individuals was Zacco platypus (43.2%) and Zacco koreanus (15.8%), respectively. Introduced from the other native rivers and exotic fish were Opsariichthys uncirostris amurensis, Leiocassis ussuriensis, and Micropterus salmoides (11.1%). The declining population density of Zacco koreanus and its subdominant status represents a change, since, up until the mid 1990's, it was widely distributed throughout the area and was the dominant species. The distribution area of Zacco koreanus decreased in size; by 2009, it no longer inhabited the lower reaches of the Naeseong Stream. On the other hand, Zacco platypus remained the dominant species throughout the area, except for the upper-reaches of the water-course. Gobiobotia naktongensis inhabited all areas of Naeseong Stream, which mainly has a sandy bottom. Analyses of the fish community revealed species diversity, even-ness and dominant indices were 0.881, 0.615, and 0.230 respectively. These results showed that the main river, in which the water width and flow are abundant and which has various habitats, has a higher species diversity (0.829) than the tributary (0.735).

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.35-43
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• 2010

Nutrient limitation and light limitation was examined for the Youngsan Lake by collecting chlorophyll $\alpha$ and other properties including light intensity, nutrient concentrations, pheopigment ratio monthly from March, 2003 to April, 2004 (except for November-January). Chlorophyll $\alpha$ was fractionated into net-(>$20\;{\mu}m$) and nano-size(<$20\;{\mu}$). Light and nutrient limitation index was calculated based on the equations incorporating the mechanisms of limitation of light and nutrients from the literature. Phytoplankton population (chlorophyll $\alpha$) was low during the wet season especially in August and increased in short-period during other seasons. Photoperiod was short during the wet season but long during the dry season. Nutrients such as phosphate and ammonium were rapidly increased in spring, 2004. Light limitation index was minimum (0.01) in August during the wet season and nutrient limitation index was relatively high (>0.4) except for May and September. Light limitation may affect phytoplankton growth rather than nutrient limitation considering that nutrient levels are high in the Youngsan Lake. Results of correlation analyses showed a negative correlation between light and nutrient limitation indices and net-pheopigment index, and a positive correlation between the indices and nano-pheopigment index. These results suggest that phytoplankton response to change of light and nutrient may be size-dependant.

• The Korean Journal of Ecology
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• v.22 no.1
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• pp.1-6
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• 1999

The author studied the soil microarthropoda's fauna, vertical distribution, seasonal fluctuation, and the relationship between the number of soil microarthropoda and environmental factor(pH) in survey area. 3949 soil microarthropoda were collected in survey area. They included Arachnida(48.6%), Collembola(23.5%), Hymenoptera(l9.9%), and Isoptera, etc. Fresh length was the longest(1l3.6 mm) in broad-leaf forest on Mt. Chilgap which is non-industrial complex area, and the shortest(46.8 mm) in pine forest at Yochon industrial complex. The population density of soil microarthropoda was the highest in summer and the lowest in winter. The number of soil microarthropoda was higher in Mt. Keryong and Chilgap, non-industrial complex area, than Yochon and Daesan, industrial complex area. The number of soil microarthropoda increased from spring to summer and decreased from autumn to winter. Vertically, soil microarthropoda were more abundant in the second layer subsoil(0∼5 cm) in spring, in the first layer(5∼10 cm) in summer and autumn, and in the third layer(0∼15 cm) in winter. Diversity index was higher in non-industrial area(1.02) than industrial complex area(0.73). Biodiversity index was the highest in the second soil layer, in pine forest on Mt. Keryong(l.60) and the lowest in the third soil layer, in broad leaf-forest, at Daesan industrial complex(0.24).

• Korean journal of applied entomology
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• v.51 no.4
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• pp.305-312
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• 2012

This study was conducted to elucidate the seasonal prevalence of adult mosquitoes and occurrence of anopheline larvae in Gimpo, Gyeonggi province, Republic of Korea. Sampling of adult mosquitoes was carried out 18 times from May to September in 2008, using light traps at six sites. A total of 48,919 individuals belonging to 16 species and 8 genera were collected. Aedes vexans nipponii (43%) was the most frequently collected, followed by Anopheles sinensis (34%) and Culex tritaeniorhynchus (14%). The seasonal prevalence of anopheline mosquitoes had a different occurrence compared to that of Cx. tritaeniorhynchus. Anopheline larvae were collected using a standard dipper (size = of 350 ml) at eight habitat types of 203 point locations. Anopheline larvae were confirmed from 138 points (63%). The average larval population per dipper was highest in the lotus plantation (6.9 individuals), followed by irrigation channel (4.5 ind.), dropwort field (3.4 ind.), fallow field (3.1 ind.), paddy field (1.8 ind.), swamp (1.4 ind.), and stream (0.2 ind.). There was no significant relationship observed between larval density and DO, pH, salinity, or distance from blood meal hosts (cowshed, pigsty, chicken-house). In the results of average nearest neighbor analysis (ANNA), the distribution of whole points for mosquito larval collection was clustered, and points with over 4.0 larvae per dipper were randomly distributed. Within the study area Haseong-myeon, those points where over 3.0 larvae were collected were of a dispersed distribution.