• Korean Journal of Environmental Agriculture
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• v.32 no.4
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• pp.304-314
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• 2013

BACKGROUND: Ecological functions of irrigation ponds were well known fact that important for biodiversity conservation in agricultural ecosystems. However, many irrigation ponds were destructed with changes of agricultural environment. The objective of this study is to appreciate the importance of ecological functions of irrigation pond. Furthermore, it presented to useful information for restorations of irrigation pond from analyses of correlations between benthic macroinvertebrate communities and locational factors of irrigation ponds. METHODS AND RESULTS: Benthic macroinvertebrate sampling was conducted from 2010 to 2012 at 15 study ponds. Comparisons of benthic macroinvertebrates diversity approached species richness and density, and statistical analyses were performed using independent t-test. A total of 131 species / 137,118 individuals of benthic macroinvertebrates were recorded during study period. Dominant taxa of benthic macroinvertebrates included Coleoptera, Hemiptera, and Odonata. Generally, benthic macroinvertebrate diversity in mountain region and existing ponds were showed higher than open field and created ponds, respectively. DCA ordination showed that benthic macroinvertebrate community was most correlated with locational characteristics of irrigation pond, and it correlated with bank type and age of pond. CONCLUSION(S): In conclusions, in order to restore ecological irrigation pond, it is necessary to consider environmental factors such as locational characteristics and bank types.

• Korean Journal of Ecology and Environment
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• v.51 no.2
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• pp.192-203
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• 2018

Headwater streams provide various microhabitats, resulting in high diversity of macroinvertebrate community. In this study, we compared the differences of communities between two adjacent headwater streams (Jangjeon stream (GRJ; GRJ1-GRJ5) and Haanmi stream (GRH; GRH1-GRH3)) in Jungwang and Gariwang mountains, Gangwon-do and evaluated the effects of habitat condition to the macroinvertebrates community composition. In order to characterize the macroinvertebrate communities and extract influential environmental factors, we applied to Cluster analysis (CA), Indicator species analysis and Non-metric multidimensional scaling (NMDS). Total 33,613 individuals in 3 phyla, 5 classes, 13 orders, 51 families, and 114 taxa (genera or species) were collected. Gammarus sp. was dominant at the upper stream of GRJ, whereas Chironomidae spp. was abundant at GRH and the downstream of GRJ. The CA classified samples into six clusters (1-6) reflecting spatial and temporal variation of benthic macroinvertebrate communities. Benthic macroinvertebrate community composition was significantly different between two adjacent streams. Sweltsa sp. 1, Psilotreta kisoensis, Rhyacophila shikotsuensis and Serratella setigera were identified as representative indicator species for clusters 1, 2, 3 and 5, respectively. Similar to CA results, NMDS revealed the spatial and temporal differences of benthic macroinvertebrate communities, indicating the difference of community composition as well as microhabitat condition. Forest composition, proportion of boulders (>256 mm), and water velocity were main factors affecting the macroinvertebrate community composition.

• Animal cells and systems
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• v.16 no.1
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• pp.69-76
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• 2012

This study was conducted to examine how a low-head dam removal (partial removal) could affect benthic macroinvertebrate communities in a stream. Benthic macroinvertebrates and substrates were seasonally sampled before and after dam removal (March 2006-April 2007). Benthic macroinvertebrates and substrates were quantitatively sampled from immediately upstream (upper: pool) and downstream (lower: riffle) sites, the location of the dam itself (middle), and immediately above the impoundment (control: riffle). After the removal, species richness and density of benthic macroinvertebrates as well as the EPT group (Ephemeroptera, Plecoptera and Trichoptera) increased to higher levels than those before the removal, while functional feeding groups and habitat orientation groups changed more heterogeneously at the upper site. At the lower site, species richness and density decreased somewhat immediately after dam removal, which was associated with an increase of silt and sand, but recovered after monsoon floods which helped to enhance substrate diversity at the upper site. Decreased dominance index and increased diversity index in both the upper and lower sites are evidence of positive effects from the dam removal. In conclusion, we suggest that even a partial removal of a dam, resulting in increased substrate diversity in the upper site, could sufficiently help rehabilitate lost ecological integrity of streams without major habitat changes.

• Journal of Korean Society on Water Environment
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• v.27 no.5
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• pp.680-688
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• 2011

This study was performed to find out the distribution aspect of benthic macroinvertebrates according to altitude in a mountain stream (a main stream: Buk stream, a tributary: Hangye stream) of Seoraksan. The survey was conducted from August to November in 2010. All survey sites were very sound because the mountain was being maintained as a protection area of the national park. Water quality and the composition of substrata were similar in all sites. Benthic macroinvertebrates of 3 phyla, 4 classes, 9 orders and 84 species occurred in the stream. Along with the decline of altitude, shredders of the functional feeding groups (FFGs) decreased, while collector filterers increased. In particular, collector filterers increased sharply at the altitude of 600 ~ 500 m (S.E.L.). Benthic macroinvertebrates showed low similarity between the uppermost site and the lower sites. Altitude appeared to be a significant factor that influence the structure and distribution of benthic macroinvertebrate community.

• Journal of Korean Society on Water Environment
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• v.32 no.1
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• pp.15-22
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• 2016

This study aims to analyze the changes in the benthic macroinvertebrate community before and after a restoration project in a eutrophic stream. Species diversity and species richness increased at the points where the channel changed from standing water to running water. However, species diversity and richness decreased at the points where only riparian restoration was implemented, and the concentration of suspended solids increased, while biochemical oxygen demand and total phosphorus decreased and the concentration of dissolved oxygen increased. In such reaches, functional feeding groups went from collector-filterers to collector-gatherers, and habitat orientation groups changed from clingers to burrowers.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.4
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• pp.259-275
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• 2021

This study explored the usefulness and implications of the Bayesian hyperparameter optimization in developing species distribution models (SDMs). A variety of machine learning (ML) algorithms, namely, support vector machine (SVM), random forest (RF), boosted regression tree (BRT), XGBoost (XGB), and Multilayer perceptron (MLP) were used for predicting the occurrence of four benthic macroinvertebrate species. The Bayesian optimization method successfully tuned model hyperparameters, with all ML models resulting an area under the curve (AUC) > 0.7. Also, hyperparameter search ranges that generally clustered around the optimal values suggest the efficiency of the Bayesian optimization in finding optimal sets of hyperparameters. Tree based ensemble algorithms (BRT, RF, and XGB) tended to show higher performances than SVM and MLP. Important hyperparameters and optimal values differed by species and ML model, indicating the necessity of hyperparameter tuning for improving individual model performances. The optimization results demonstrate that for all macroinvertebrate species SVM and RF required fewer numbers of trials until obtaining optimal hyperparameter sets, leading to reduced computational cost compared to other ML algorithms. The results of this study suggest that the Bayesian optimization is an efficient method for hyperparameter optimization of machine learning algorithms.

• Journal of Environmental Science International
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• v.27 no.11
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• pp.1117-1127
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• 2018

This study was carried out to gather basic data for the purpose of proposing a plan to improve the water quality and conserve the aquatic ecosystem of the Singu Agricultural Reservoir in Korea. The water quality, sediment composition, benthic macroinvertebrate distribution, and fish distribution in the Singu Reservoir were analyzed; the reservoir is located close to farmlands, forests, villages, and livestock breeding areas. The results of the water quality analysis are as follows: 5.8~7.8 mg/L for dissolved oxygen, 13.1~20.7 mg/L for chemical oxygen demand, 14.4~18.8 mg/L for suspended solid, 0.96~1.70 mg/L for total nitrogen, 0.07~0.11 mg/L for total phosphorous, and $41.9{\sim}49.8{\mu}g/L$ for $chlorophyll-{\alpha}$. In total, 75 benthic macroinvertebrate specimens belonging to 4 classes, 7 orders, 14 families, and 17 species were recorded. The ecological scores of the benthic macroinvertebrate communities ranged from 11 to 23. Fish specimens recorded belonged to two families and four species. The dominant fish species were Carassius auratus and Pseudorasbora parva, both of which are water-pollutant tolerant species.

• Journal of Korean Society on Water Environment
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• v.34 no.6
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• pp.602-620
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• 2018

Korean benthic macroinvertebrate community from 959 sites and 14 environmental factors that could affect the biological distribution were surveyed and analyzed. The 438 taxa were divided into six groups according to TWINSPAN. Based on the environmental factor values corresponding to each taxon, the average and range of environmental factors for each biological group tended to increase or decrease in eight environmental factors (altitude, slope, current velocity, fraction of fine particles in substrates, turbidity, $BOD_5$, T-N and T-P). As a result of discriminant analysis (hit ratio: 69.6 %), environmental factors that significantly influence the distribution of each biological group were $BOD_5$, altitude, catchment area, T-N, T-P and fraction of fine particles in substrates. The discriminant functions 1 and 2 classified the existing six biological groups (clustered by TWINSPAN) into five (group 1: highland highly sensitive group; group 2: lowland sensitive group, group; 3 and 4: lowland slightly tolerant group; group 5: lowland tolerant group; group 6: lowland highly tolerant group). Most of the benthic macroinvertebrates were identified in the species level. However, a few others were identified in genus or family level, too. Even the organisms belonging to the same genus or family may prefer different environmental factors in the species level, the identification of characteristic of the habitat environment preferred by organism and species level identification of these organisms are utmost. The results of this study may be used as basic information on environmental factors which can be considered in preservation and restoration research for biodiversity.

• Journal of environmental and Sanitary engineering
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• v.18 no.2
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• pp.16-26
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• 2003

Analysis of benthic macroinvertebrate community and biological estimation of water quality was conducted at the national park of Mt. Jiri and its nearby area in Gurye, Sancheong and Hadong-gun from June to November, 2002. Total taxa of benthic macroinvertebrates were 124 species, 45 families, 15 orders, 5 classes in 3 phyla. Aquatic insects were 33 species in ephemeroptera, 28 species in Trichoptera, 21 species in plecoptera, 13 species in Diptera, 8 species in odonata, 5 species in hemiptera and 5 species in coleoptera, respectively. Non-insects were 5 species in Mollusca, 2 species in Hirudinea, 1 species in oligochaeta and 1 species in crustacea, respectively. Ephemeroptera, trichoptera and plecoptera as indicators in clean water were very abundant. Occurrence species at each survey area was 68 species at Mt. 1025-goji, 59 species at Mt. Eungseok-bong, 57 species at Mt. Wangdeung-jae, 50 species at Mt. Cheonwang-bong and 39 species at Mt. 645-goji, respectively. Mean species diversity indices at Mt. Cheonwang-bong, Mt. 1025-goji, Mt. Wangdeung-jae, Mt. Eungseok-bong and Mt. 645-goji were 3.33, 3.03, 3.41, 3.02 and 2.91, respectively, According to the saprobic system based on the species diversity indices of benthic macroinvertebrates, most survey areas except some sites are determined as Limnosaprobic area.

• Korean Journal of Ecology and Environment
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• v.54 no.2
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• pp.87-95
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• 2021

Macroinvertebrates in forest streams affect the overall health of other streams in the same water system. In this study, we compared differences in the benthic macroinvertebrate community at two headwater streams located at different latitudes in the southern and northern parts of South Korea. We calculated the community temperature index (CTI), which represents the thermal preferences of the benthic communities. Hierarchical cluster analyses (HCA) were conducted to compare the similarities among sampling sites. In addition, we analyzed the relationship between community composition and environmental and community characteristics using non-metric multidimensional scaling (NMDS). Our results showed that CTI was significantly different between the two regions, indicating that these benthic macroinvertebrate communities have different thermal preferences. These two regions were clearly distinguished from each other in the HCA; furthermore, seasonal differences in benthic community composition were observed within each region. The functional feeding groups present in the benthic macroinvertebrate communities were different even though their habitat was similar.