• Animal Systematics, Evolution and Diversity
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• v.11 no.1
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• pp.39-64
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• 1995

A faunistic and ecological study on the occurrence of freshwater cladocerans and copepods was accomplished from Chindo, South Korea. Collections were made from total 35 stations, comprising the various freshwater habitats like reservoirs, streams, swamps, bogs, ricefields, ditch, pond, and spring during the periods of July 23-25, and November 1-3 in 1994. Twenty seven cladoceran species of 17 genera of 6 families in 2 orders, and 28 copepod species of 21 genera of 6 families in 3 orders were collected during this research period, of which Daphnia obtusa Kurz and Elaphoidella bidens (Schmeil) are newly recorded from Korea. In reservoirs, Diaphanosoma sp. and Thermocyclops taihokuensis were dominant in July, and then succeeded by Bosmina longirostris and Cyclops vicinus vicinus in November. Thermocyclops crassus co-occurred with 7: taihokuensis at both seasons, was frequent in November after T. taihokuensis precipitately decreased. In other stagnant waters, 7: taihokuensis and Moina weismanni were dominant at ponds in July and in November, respectively. At ricefields in July Moina macrocopa and T. taihokuensis were dominant, but in November M. macrocopa and Paracyclops fimbriatus were. At streams, cladocerans were relatively rare, but became more rich in November. The representative cladoceran species were Bosmina longirostris as a plankton, and Chydorus sphaericus as a epibenthic species. Concerning copepods, nearly all the stations of streams except a few ones adjacent to seashore showed the similiar species constitutions, of which E. serrulatus and M, pehpeiensis were most frequent and abundant. At a mountain streamlet and a spring, the occurrence of Alona sp., Attheyella byblis Chang and Kim, 1992 and A. tetraspinosa Chang, 1993 is quite interesting and deserved much attention in the taxonomical point of view. Seventeen major cladocerans and copepods from lentic habitats and 13 major cladocerans and copepods from lotic habitatats were clustered using average taxonomic distance and UPGMA to infer the co-occurrence relations among species. As for lentic habitats, two large phena were appeared at first. The one phenon consisted of Diaphanosoma sp. and T taihokuensis, and showed its predominancy over the various habitats and its dominancy was rapidly decreased in November. The other phenon frequently occurred rather in November, and subdivided into three subgroups. On the other hand, as for lotic habitats, 13 species were also grouped into 2 large phena. The first one comprised 4 species, which were dominant and highly frequent at nearly all the lotic habitats, and subdivided into three subgroups according to their seasonal fluctuation types. The second one was also subdivided into three phena, the first of which comprised only one species, Microcyclops varicans, and occurred at most of the stations along stream with steadiness through the research period; the second phenon, Chydorus sphaericus, occurred much frequently in November; the last phenon included a few heterogenous subgroups.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.374-381
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• 2012

In this study, ecological characteristics of Zacco platypus population in Lake Hoengseong region, including the up-and downstream in Lake, were investigated from April to November, 2010. The results compared with regional dynamics of Z. platypus population showed a dominant population among the other fish population, and also upstream has relatively high as 1,707 (78.70%) individuals than those of other sites. The regression coefficient (b) in relation to length-weight on Z. platypus population were 3.28 which appeared relatively a stabilized habitat condition in Lake Hoengseong region and 3.28 at the upstream and 3.10 in Lake Hoengseong and 3.09 at the downstream. Condition factor on Z. platypus population in Lake Hoengseong region showed stabilized population as 0.003 value, and especially the condition factors at the upstream were relatively higher than those at the downstream and Lake Hoengseong, indicate that Z. platypus population at the upstream displayed to be maintained as the most good condition in relation to trophic states. As a results of compared with body size on Z. platypus population, was investgated as highly distribute between 30~50mm and 70~90mm at upstream; 60~80mm in Lake Heongseong; 70~100mm at downstream, respectively. As a results, Z. platypus population at the upstream among Lake Hoengseong region displayed the most stabilized growth condition, and Z. platypus population were inhabitable in lotic and lentic environments based on good habitat condition.

• Korean Journal of Environmental Biology
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• v.33 no.3
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• pp.330-337
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• 2015

Pre-monsoon dynamics of zooplankton community were investigated in Yongwol West River tributary; wetland shaped Korean Peninsula. Zooplankters were collected at three sites (stn 1: Yongwol West River, stn 2: Pyungchang River, stn 3: Jucheon River) monthly during the period between March and July 2014 except April. Totally 58 taxa of zooplankton occurred, consisting of 27 species of rotifer, 18 species of cladoceran, eight species of copepod, four kinds of aquatic insect larvae and one nematod. Lotic cladocerans of Alona spp. belonging to Chydoridae occurred frequently while typical lentic ones of Bosmina spp. and Daphnia spp. were not distributed, then sampling sites may be located in lotic waters. Zooplankton abundance recorded as $4,451-8,011indiv{\cdot}m^{-3}$ in Jucheon River but never exceeded $500indiv{\cdot}m^{-3}$ in other rivers. In Yongwol West River, dominant taxa were aquatic insect larvae from March through June and succeeded to cladocerans and copepods in July. Similar succession was observed in Jucheon River where aquatic insect larvae dominated in March and changed to cladocerans and copepods from May with high abundance. No such succession of zooplankton community was detected in Pyunchang River. Species diversity indices were the highest in Yongwol West River except in March. High values of dissolved oxygen ($9.0-11.0 mg{\cdot}liter^{-1}$) may show the characteristics of mountain streams. Water temperature increased gradually from $10.1^{\circ}C$ to $27.9^{\circ}C$ and pH varied within generally high range between 7.9-8.9, respectively. High value of pH seems to be derived from lime stone mines and cement factories around the studied area.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.437-450
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• 2010

Ecological influences of indigenous freshwater bivalve Unio douglasiae on the water quality and epilithic diatom community was examined with artificial stream (AST), which constructed in a laboratory daily receiving the eutrophic lake water. For the colonization of new periphyton community, forty commercial slide glasses were deposited as a substrate into the lowest part of each AST. Prior to 1 week, the AST was operated to induce the freely-colonization of the algal community in the absence of mussels. After the mussels was introduced at 435 indiv. $m^{-2}$ between step 1 and step 5, the passed water and substrates were daily collected to analysis the change of water quality and lotic and lentic algae abundance for 10 days. Compared to the control, turbidity (60.0% of control), suspended solids (62.5%), and chlorophyll-$\alpha$ (72.2%) in mussel-passed waters were decreased significantly, while a strong increase of ammonia (up to 800% of control) was companied with the decrease of dissolved oxygen (19.5% of control) and total phosphorus (23.9%), respectively. On average, the concentrations of suspended solids (67.0% of control) and chlorophyll-$\alpha$ (89.4%) in mussel-treated substrates were remarkably increased, however algal abundance in its water simultaneously decreased. These results indicate that incidentally or purposely mussel introductions can decrease organic matter of the stream and increase transparency of stream water, however, mussel-mediated nutrient and pseudofeces release may stimulate the adverse growth of periphyton or phytoplankton community in the lower stream or reservoir.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.138-144
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• 2006

Algal growth potential test (AGPT) has been used as a tool for assessing biological productivity potential in the aquatic ecosystems. This study was conducted to compare the productivity potentials of large reservoirs (Lakes Andong, Hapchon and Jinyang, and Naktong estuarine dam) and river sites (Sangju, Koryung, and Samlangjin) located in the Naktong River watershed. AGPT was conducted in both non-monsoon and mosoon season (February, April, July and September) of 2003, using Microcystis aeruginosa as a test alga. The AGPs in the reservoirs were relatively much lower than those of river sites. The river AGPs increased towards upstream close to the influent streams, while it generally decreased towards downstream. Immediately after the abrupt increase in influent discharge in summer, the AGP became similar between midstream and downstream sites. The water quality of river and reservoirs deteriorated during the drought period in accordance with AGP: it was the highest during this period. The AGPs showed the closest correlation with the P concentration, leading to the conclusion that bioavailable P is highly influential to the algal growth in both lentic and lotic ecosystems in the Naktong River watershed. Based on the AGPs, the water quality of tested sites was likely eutrophic. Our results suggest that AGPT be a useful tool in evaluating the productivity potential and trophic state of the water body as well as determining the nutrients that limit the growth of algae.

• Korean Journal of Environment and Ecology
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• v.28 no.4
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• pp.424-431
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• 2014

Analysis of the fish community in Yeongwol Hanbando wetland in Korea was investigated from April to October 2012. During the survey period, total 33 species belonged to 10 families and 7,107 individuals. There were 18 Korean endemic species (52.94 %), including to Acheilognathus signifer. Also, the dominant species were Zacco koreanus at St. 1, 2, 3 & 5, as well Acheilognathus signifer at St. 6, and Pseudopungtungia tenuicorpus at St. 7, respectively, and these species were inhabited in the midstream. But at St. 4, Carassius auratus was dominance, so there appeared to characteristics of downstream or lentic habitat. Also, according to the similarity analysis on fish species and their individuals in each sites, they were divided into three major groups (A,B and C). Among them, group C (St. 4) showed the special inverse characteristics as a stagnant pond. unlike the river branch (group A) and anthropogenic disturbances receiving stream point (group B), Therefore, the ecosystem of Yeongwol Hanbando wetland is considered to very unique and these characteristics are not found in other stream ecosystems and it is confidently believed that the ecological value is very high.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.301-310
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• 2008

This study was to analyze characteristics of fish compositions and longitudinal distribution, based on trophic and tolerance guild at 22 sampling sites of Yeongsan River watershed during 2003$\sim$2006, and also to compare before and after the estuary dam construction. The collected fishes, based on catch per unit effort (CPUE), were 44 species in the watershed and dominant fishes were Zacco platypus, Acheilognathus macropeterus, Zacco temminckii and Carassius auratus. According to comparative analysis of fish in the non polluted sites (NPS) vs. polluted sites (PS), the number of species and individuals was lower by 70% in the PS than the NPS, indicating ecological degradations by chemical pollutions or/and habitat modifications. The relative abundance of sensitive and insectivore species decreased as the stream order increases, while tolerant and omnivore species increased with the stream order. In this survey, largemouth bass (Micropterus salmoides), which is a top-carnivore and exotic species, may influence trophic guild system throughout active predations on endemic species, resulting in modifications of ecological functions. The construction of estuary dam on Yeongsan River in 1981 resulted in wider lacustrine zone and desalinated through limitation of seawater input. These physical changes have caused increases of lentic dwelling species and limited fish migrations (i.e., eel). Overall, fish fauna and composition analyses showed that the number of species and individuals in this water body may be reduced due to inputs of pollutants from the watershed, habitat modifications, and increases of exotic species (largemouth bass). For these reasons, effective lake management strategies are required for the ecosystem conservation.

• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.173-184
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• 2020

Irrigation ponds, 'dumbeong', which are artificially constructed water resources for traditional farming, serve as a biological shelter connecting seasonally created rice paddy fields to local freshwater ecosystems. This 2018 study surveyed 143 irrigation ponds in the western Civilian Control Zone (CCZ) area from August to September, revealing species diversity and community characteristics of benthic macroinvertebrates. A total of 13,454 individuals of macroinvertebrates were captured and classified into 3 phyla, 5 classes, 17 orders, 59 families, 192 species. Among Insecta, the most frequently recorded order was Odonata, 55 spp.(33.7%), followed by Coleoptera, 52 spp. (31.9%), Hemiptera, 34 spp. (20.8%), Diptera, 17 spp. (9.8%), Ephemeroptera, 3 spp. (2.4%), Trichoptera, 1 spp. (0.6%) and Lepidoptera, 1 spp. (0.6%). Taxon of non-Insecta consisted of Mollusca, 14 spp. (48.2%), Annelida, 11 spp. (37.9%) and Arthropoda, 4 spp. (3.4%). The analysis of Diversity Index (H'), Species Richness Index (RI), Dominance Index (DI) and Evenness Index (J') revealed the general stability of communities in the study sites. A total of 28 rare species were found in 98 study sites, including three endangered species designated by the Ministry of Environment. These results showed that the species diversity and rarity of macroinvertebrates in the study area were greater than those of previous research on lentic wetlands (lake, etc.) and national conserved wetlands(Upo-swamp, etc.) in Korea. A conservation planning of aquatic ecosystems in the western CCZ area, therefore, should focus on conservation of irrigation ponds.

• Journal of Korean Society of Forest Science
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• v.101 no.3
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• pp.454-460
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• 2012

This study was conducted for determining the influence of Sediment Control Dam dredging on benthic macroinvertebrate communities in mountain stream of Gyeongsangbuk-do. The sediment control dams were surveyed before and after dredging from mountain streams of Yecheon, Yeongju and Bonghwa in Northern part of Gyeongsangbuk-do. Sampling was taken at upper and down from 3 experimental sites and 2 control sites during May to August 2011. The identified species before dredging were 56 belonged to 31 families, 11 orders, 6 classes and 4 phyla, but after dredging it has decreased to 51 species belonged to 27 families, 10 orders, 5 classes and 4 phyla. The microhabitat damage of benthic macroinvertebrates occurred at experimental sites after dredging of sediment control dams led to reduction of the number of species and individuals. Especially, upper stream of experimental sites showed the reduction of an average of 38% species. In general, species diversity indices and species richness indices decreased after dredging; however, dominance indices increased at experimental sites. In the upper stream of experimental sites, the microhabitat damaged and became pool due to dredging. Also, velocity of flow decreased and the river bed became simply due to the sedimentary matter being finer than sand and silt. As a result, composition of functional feeding groups and functional feeding groups were relatively simpler at upper stream and the degree of community differences was greater between upper and down stream. Also, Chironomidae spp., Ephemeridae spp., and Gomphidae spp. to prefer where slow velocity of flow and lentic increased in a greater rate, and the EPT/C index to indicate the balance of the community decreased.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.189-196
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• 2020

Mosquitos serve as vectors for diseases, causing inconvenience as well as a threat to human life and health. Concern about mosquitos introducing and spreading new diseases has been intensifying. We observed a variety of mosquito habitats based on land cover classification from Korea's Ministry of Environment, and the mosquito species that could appear were classified according to the each habitat type. Finally, we suggested the best control methods for each type of habitat considering habitat characteristics and the ecological traits of mosquitos. Urban areas harbor various habitats for pests, contributing significantly to mosquito habitats. Control must be performed regarding larva and adults because various sources for habitats exist. Public mosquito control programs such as educational training, as well as information brochures can be effective in managing mosquito populations and public health. Agricultural areas show high densities of mosquito larva to lentic zones such as reservoirs, wetlands, paddy fields. So, biological control using natural predators may be effective in controlling mosquito populations. Forests are major habitats for Aedes albopctus, so physical controls should be deployed for residents living nearby, and excessive deforestation should be minimized. Other areas including aquatic ecosystems should be adopted regarding biological control using Bti (Bacillus thuringiensis var. israelensis) and chemical control for eradicating mosquitos. We classified habitats into four types of land cover patterns considering ecological traits and habitat preference, and suggest adequate control methods for each habitat type. Our suggestion can be used to positively contribute toward effective managing mosquito's density and reducing the damage to public health.