The changes on community structures of benthic macroinvertebrates, relevance to the environment and interrelationship between benthos were studied over two years in stream with large environmental disturbance, which caused by localized heavy rain during Typhoon Chaba in October 2016. As a result, the number of species and individuals were increased after localized heavy rain, especially numbers of individuals of Ephemeroptera and Plecoptera were greatly increased. On the contrary, those of Semisulcospira libertina and Semisulcospira forticosta of Mesogastropoda were greatly decreased. Dominant species was Baetis fuscatus of Ephemeroptera, numbers of species and individuals of Ephemeroptera, Plecoptera and Trichoptera(EPT group) were dramatically increased from 26 species, 110 individuals to 32 species, 365 individuals respectively. This suggests that the change of river bed and flow velocity due to heavy rain provided a suitable environment for the EPT group that preferred the rift of a stream. In the functional feeding group, only gathering collectors and filtering collectors were identified in autumn of 2017 because some functional groups preferentially adapted to the changed environment. The interspecific competition and environmental condition were the worst in autumn after heavy rain due to the increase individuals of some species. The ecological score of benthic macroinvertebrate community(ESB) was higher after the heavy rain than before. Results of the Group Pollution Index(GPI), Korean Saprobic Index(KSI) and Benthic Macroinvertebrate Index(BMI) were similar to those before and after heavy rainfall. Therefore, ESB was the most discriminating method for estimating the biological water quality in this study. Some species that are sensitive to water quality changes still appear or increase individuals in the area under investigation after the heavy rain. On the other hand, the individuals of some pollutant species decreased. This is thought to be because the habitat fluctuation caused by heavy rainfall has improved the water environment.

In the present study, the community distribution, functional feeding groups, and habitat groups of the benthic macroinvertebrates from Gayasan National Park were investigated at eight different sites from 2015 to 2016. The correlation between habitat altitude and each group type was analyzed statistically. Biodiversity indices, including dominance, diversity, richness, and evenness indices, were calculated. The results showed a total of 4,216 individual benthic macroinvertebrates were collected, including 4 phyla, 6 classes, 16 orders, 40 families, and 100 species. Gammarus sobaegensis was dominant with 0.141% dominance, and the subdominant species was Epeorus nipponicus with 0.088% dominance. The EPT group(Ephemeroptera, Plecoptera and Tricoptera) accounted for 71.00% of the total species and 67.69% of the total individuals. The number of scraper species was highest, and the number of gathering collector individuals was highest among functional feeding groups. The individual number of scrapers(r=-0.358, p ˂ 0.05) and gathering collectors(r=-0.343, p ˂ 0.05) decreased with increasing altitude. The numbers of species and individuals of clingers and sprawlers were highest among the habitat groups. The individual number of clingers(r=-0.547, p ˂ 0.01) and burrowers(r=-0.331, p ˂ 0.05) significantly decreased with increasing altitude. The diversity and richness indices were higher in St. 3 than in the other sites. The dominance index was highest in St. 2, and the evenness index was highest in St. 7. We evaluated the biological water quality with several known methods, and concluded that ESB(Ecological score of benthic macrovertebrates community) and GPI(Group polution index) were more suitable than KSI(Korean saprobic index) and BMI (Benthic macrovertebrate index) to assess the biological water quality of Gayasan mountain stream water.

This study identified the effect of changes in the riverbed on the benthic macroinvertebrate communities. The benthic macroinvertebrates collected from the surveyed sites belonged to 119 species, 65 families, 20 orders, and 7 classes in 4 phyla. The number of Ephemeroptera, Plecoptera, and Trichoptera (E.P.T) species was 42, 10, and 8, respectively, in the tributary, confluence, and Nakdong River sites. Lotic species (Hydropsychidae) showed a high density at the tributary sites, whereas lentic species (Chironomidae) showed a high density at the confluence and Nakdong River sites. Community analysis showed that the Dominance Index (DI) was 0.54 in tributary sites, and dominance indices increased closer to the Nakdong River sites. The diversity index (H’) was inversely proportional to DI. The ratio of Burrowers species (BU) at the surveyed sites increased closer to the Nakdong River sites. Analysis of common species showed 37 species (34.6%) between the tributary and confluence sites and 66 species (51.5%) between the confluence and Nakdong River sites.

The distribution characteristics of functional feeding groups and biological evaluation of water quality with benthic macroinvertebrates were investigated from 2013 to 2014 in the mountain streams of Jirisan National Park. Both quantitative and qualitative collection had been performed six times during study periods in twelve sites located at upstream, midstream and downstream of four valleys, Chilsungol, Baemsagol, Daesunggol and Piagol of freshwater ecosystem in Jirisan National Park. As results, the total collected benthic macroinvertebrates were 3 phyla, 4 classes, 11 orders, 37 families, 107 species and 4,028 individuals. In 2013, 3 phyla, 4 classes, 10 orders, 32 families, 89 species and 1,829 individuals were collected. And in 2014, 3 phyla, 4 classes, 9 orders, 31 families, 80 species and 2,199 individuals were identified. The total dominant species was Ecdyonurus kibumensis, and EPT groups occupied 80.39% of total species number. Biotic indices were also compared to site and to season. The dominant index (DI) was highest at the downstream of Baemsagol in the spring of 2013, and the evenness index (J') was highest at the downstream of Daesunggol in the summer of 2013. Both diversity index (H') and richness index (RI) were highest at the upstream of Baemsagol in the summer of 2014. The correlation between altitude above sea level and functional feeding groups of benthic macroinvertebrates was also researched in this study. As a result, the species number of shredders and predators have significantly increased according to the increase of the altitude of their habitat. On the other hand, individuals of gathering collectors have increased according to the increase of altitude. The biological water quality was evaluated and compared with several methods in this study, and we suggest that ESB and GPI are more appropriate than KSI and BMI to evaluate biological water quality of mountain stream water.

We assessed the distribution of benthic macroinvertebrate at four surveying sites in Upo Wetland, a Ramsar site and the largest wetland in Korea, from February 2006 to November 2013. A long-term ecological monitoring was done monthly by using quantitative sampling method with dip net for analyzing the community change and correlation between the biodiversity and the environmental factors because environmental factors have a decisive effect on the community structure of the benthic macroinvertebrates. Total samples from the Upo Wetland area were classified into 3 phyla, 6 classes, 17 orders, 68 families, 176 species, and 25,720 individuals. Among the 176 species, 62 of the species had not been previously reported in this area. Asellus sp., Diplonychus esakii, and Gyraulus chinensis were the most common species in Upo Wetland. The change patterns of annual species diversity and species richness were calculated by using the average number of monthly occurring species and individuals. Diversity index increased from March to May and decreased after that showing lower diversity indices in July and August. It increased again in September and in October. Richness index showed similar tendency and fell around February and July, followed by a rising tendency around May and October. Correlation and regression analyses were performed with the change of biodiversity and each environmental factor. We found that water temperature have very significant positive correlation with species diversity in spring, and have significant indices in autumn and winter. On the other hand, precipitation showed a significantly negative correlation value in summer and autumn suggesting it has an effect on the community structure of benthic macroinvertebrates.

Benthic macroinvertebrates were seasonally sampled from upstream and downstream of the Gunwi Dam construction site from 2006 to 2012. Totally 148 and 165 species were collected at the upstream and downstream sampling sites, respectively. At the upstream area after dam construction, there was no significant change of the numbers of non-insect taxa, but at the downstream area, the non-insect taxon numbers were increased gradually. The individual ratio of Ephemeroptera and Diptera had higher value than the other taxa in both of up and downstream. The trichopteran individual ratios were increased in upstream sites, but decreased in downstream sites from 2010. Also, non-insects and coleopteran individual ratios were decreased in upstream, but increased in downstream after completion of dam construction. The annual range of fluctuation in community indices narrowed after construction. According to a functional feeding group analysis, the individual ratios of FC (Filtering Collector) were increased, and GC (Gathering Collector) and SC (Scraper) were decreased in upstream sites annually. In contrast, the annual individual ratios of FC were decreased, and GC and SC were increased in the downstream sites.

Hydraulic habitat analysis of Benthic Macroinvertebrates was performed at Gapyeong stream. Among the kinds of the Benthic Macroinvertebrates, the most representative ones are the Ecdyonurus kibunensis from the clingers, Paraleptophlebia cocorata from the swimmers, Chironomidae spp from the burrowers, Psilotreta kisoensis iwata from the sprawlers. They showed different habitat types by the hydraulic conditions such as flow velocity, depth and particle size of riverbed materials. Habitat conditions of swimmers were determined mainly by the flow velocity rather than flow depth or riverbed materials. Burrowers prefer sand and silt, and inhabited at the riverbed. Sprawlers prefer cobble or boulder and inhabited for velocity of 0.05～0.15 m/s. Clingers prefer pebble or cobble and inhabited for velocity of 0.06～0.15 m/s. Although the habitats of each groups are different by the hydraulic properties, they were found to be different mainly by the water velocity.

The studies on community structure of benthic macroinvertebrates and environmental survey in selected four sites were performed on wetland Upo from 2008 to 2009. The lowest water temperature was measured at Upo and Mokpo showing 7℃ in February of 2008 and 2009 respectively. The highest water temperature was measured at Upo showing 32℃ in August of 2009. The lowest pH was measured at Topyeong with 5.3 in August of 2009, and the highest pH was measured at Mokpo with 10.1 in August of 2008. Generally the levels pH of 2008 were higher than those of 2009. The range of electric conductivity to the sites was big. Overall, the higher electric conductivity was seen at Sajipo and the lower one was seen at Mokpo. The level of Dissolved oxygen was lowest at Upo with 5.53㎎/ℓ in August 2008, and it was highest at Upo with 14.76㎎/ℓ in February of 2008. The investigation was performed with both quantitative and qualitative collecting methods from four surveying sites, Upo, Mokpo, Sajipo and Topyeong. Through the eight times of seasonal survey, 6 classes, 17 orders, 59 families, 131 species and 5460 individuals of benthic macroinvertebrates were collected. 6 classes, 17 orders, 53 families 106 species and 2439 individuals were identified in 2008, and 6 classes, 16 orders, 44 families, 93 species and 3021 individuals were collected in 2009. The number of species was decreased in 2009 comparing that of 2008, however, the number of individuals were increased in 2009. The dominant species and the subdominant species was Plea (Paraplea) indistinguenda and Diplonychus esakii with 20.16% and 11.90% of dominant indices respectively. From the community analysis, both the species diversity index and the species richness index were highest in Topyeong showing 4.743 and 9.054 respectively. The similarity evaluation to the investigation sites with the species in there showed very high similarity among Upo, Mokpo and Sajipo showing 5 or lower levels of distance cluster combine.

The distribution of benthic macroinvertebrates in Daecheon stream, an urban stream of Busan, was investigated to analyze the community structure of benthic macroinvertebrates. The collection was peformed monthly at five(A~E) sites divided into three parts, upper, middle and lower, of stream from January to November, 2004. In physicochemical analysis of environmental factors, water quality parameters such as BOD, COD, conductivity and ABS were relatively increased in sites B and C. Whereas sites A, D and E showed little variations with good water quality parameters. However, water quality parameters in all surveyed sites showed gradual decrease with time toward improvement of water quality. A total of 8,226 individuals including 4 phyla, 6 classes, 9 orders, 302 families and 44 species were identified from five sites. The most dominant group was insect(class Insecta), and order Ephemeroptera and Diptera among insect was the largest member in species(30.6%) and individuals(75.0%) of benthic macroinvertebrates, respectively. The primary dominant species were Gammarus sp. and Ephemera strigata in site A, whereas Chironomus sp. and Brenchiura sowerbyi were dominated commonly in the other sites. In community analysis of benthic macroinvertebrates of Daecheon stream diversity index showed relatively low values, whereas dominance index was significantly high. Diversity index was the highest in site A, whereas the dominance index was the highest in site B. However, diversity index showed gradual increase with time showing adverse mode in dominance index. From these results, it can be suggested that long-term ecological monitoring of benthic macroinvertebrate fauna is needed for sustainable management of Daecheon stream.

The study on community structure of benthic macroinvertebrates from wetland Woopo was conducted for the long-term ecological monitoring. The wetland Woopo is located in Changnyeong-Gun, Gyeongsangnam - Do of Korea. In 2006, we investigated the seasonal variation of benthic macroinvertebrates with quantitative and qualitative collecting methods. The collection was performed monthly at four surveying region, Woopo, Sajipo, Mokpo and Topyong stream. In this study, 6 classes, 16 orders, 48 families, 95 species were identified on group of benthic macroinvertebrates. The species diversity index and the species richness index were the highest in Topyung region and it was 3.222 and 10.216 respectively. The two species, Cercion calamorum and Cloeon dipterum were quantitatively collected for 9 months. The changes of body lengths of 50 individuals were recorded and the advanced growth on the two species was expected from present study.

The distribution of benthic macroinvertebrates of Shinbulsan wetland was investigated. This study was focused on the degree of recovery of habitat by comparing the community structure of benthic macroinvertebrates of zone D to that of zone A, intact habitat. The zone D was destructed due to the construction of a golf club and the survey was performed in zone A and zone D of Shinbulsan wetland. The seasonal survey was performed in April, July and September from 2006 to 2007. From the sampling, 2 phyla, 3 classes, 9 orders, 31 families, 69 species and 1155 individuals of benthic macroinvertebrates were collected. From zone A, 2 phyla, 3 classes, 9 orders, 23 families, 54 species and 678 individuals were identified. From zone D, 2 phyla, 3 classes, 9 orders, 23 families, 43 species and 477 individuals were identified. Species diversity and species richness were higher in zone A than in zone D. The recovery of zone D was inefficient as humidity of soil was not enough to live macroinvertebrates. Also, an endangered species of macroinvertebrates, Nannophya pygmaea was found during this investigation.

Community structure of benthic macroinvertebrates was investigated from Gigye stream, Pohang, Korea from May to November, 2007. As results, total of 108 species of macroinvertebrates under 49 families, 15 orders, 5 classes in 3 phyla were identified. The number of species was the most abundantly revealed in aquatic insects (class Insecta) with 86 species (82.6%) under 7 orders. The phylum Mollusca (10 species, 9.2%) and the phylum Annelida (6 species, 5.6%) were followed in order. In the class Crustacea, 6 species (5.6%) were distributed. In aquatic insects, the order Odonata was the most abundant taxon (20 species, 23.3%). Seventeen species (19.8%) of the order Ephemeoptera and 16 species (18.6%) of the Coleoptera were followed. The primary dominant species in the stream was Cloeon dipterum of Ephemeroptera. For community analysis, the values of diversity index (H'), evenness index (J'), dominance index (DI) and richness index (RI) were studied and the average values of them were 5.65, 0.84, 0.13, and 13.18, respectively.

밀양강 수계 7개 지점에 대하여 1997년 4월부터 12월까지 5회에 걸쳐 채집된 저서성 대형무척추동물의 군집분석 및 저서성 대형무척추동물에 의한 생물학적 수질평가 결과를 요약하면 다음과 같다. 분류군은 총 3문 8강 15목 37과 45속 81종으로서 빈모류 1종, 거머리류 2종, 복족류 6종, 부족류 5종, 갑각류 2종, 곤충류 65종으로 곤충류가 가장 많았다. 전체 지점에 대한 평균 개체수 현존량은 815개체/㎡였다. 이 중 곤충류(약80%)가 가장 많았으며, 다시 곤충류 중에는 하루살이류(약 70%)와 날도래류(약 18%)가 주를 이루었다. 각 지점별 평균개체수 현존량을 보면, 제1지점인 청도천의 경우 262개체/㎡(32.2%)로서 가장 많은 출현율을 보였고, 제7지점인 밀양강 끝지점의 경우 38개체 /㎡(4.7%)로서 가장 출현율이 낮았다. 전체 평균 수준에서의 제1우점종은 Ecdyomurus levis Navas였으며, 우점도지수는 0.3이었다. 각 지점별 우점종을 보면 제1지점부터 제5지점까지는 Ecdyomurus levis Navas이였고, 제6지점과 제7지점은 Hirudinidae sp.1이었다. 그리고, 전체 평균 수준에서의 다양도지수는 2.66이었다. 조사지점별 평균 다양도 지수를 보면 제4지점이 가장 높았으며(H'=3.47), 다음은 제2지점, 1지점, 3지점, 5지점, 6지점, 7지점의 순이었다. 생물학적 지표종을 중심으로한 수질평가에 의하면, 밀양강 전체의 평균은 군오염지수(GPI) 1,49로서 β-mesosaprobic의 II급수로 평가되었다. 각 지점별로는 제3지점의 경우 Oligosaprobic의 I급수로서 가장 양호한 수질이었고, 제1지점과, 제2지점, 제4지점, 제5지점은 β-mesosaprobic의 II급수로, 제6지점은 β-mesosaprobic의 III급수로 평가되었다. 그리고, 제7지점은 α-mesosaprobic의 III급수로서 가장 수질이 불량한 것으로 평가되었다.