Estuary is important in terms of biodiversity because it has the characteristics of transition waters, created by the mixing of fresh- and seawater. The estuarine water circulation provides a variety of habitats with different environments by inducing gradients in the chemical and physical environment, such as water quality and river bed structure, which are ultimately the main factors influencing biological community composition. If the water circulation is interrupted, the loss of brackish areas and the interception of migration of biological communities will lead to changes in the spatial distribution of biodiversity. In this study, among the sites covered by the Estuary Aquatic Ecosystem Health Assessment, we selected study sites where changes in biodiversity can be assessed by spatial gradient from the upper reaches of the river to the lower estuarine area. The α-, γ- and β-diversity of diatom, benthic macroinvertebrates, and fish communities were calculated, and they were divided into open and closed estuary data and compared to determine the trends in biodiversity variation due to estuarine circulation. As results, all communities showed higher γ-diversity at open estuary sites. The benthic macroinvertebrate community showed a clear difference between open and closed estuaries in β-diversity, consequently the estuarine transects were considered as a factor that decreases spatial heterogeneity of their diversity among sites. The biodiversity trends analyzed in this study will be used to identify estuaries with low γ- and β-diversity by community, providing a useful resource for further mornitoring and management to maintain estuarine health.

We attempted to estimate potential habitats of Clithon retropictus and to determine the community structure of benthic macroinvertebrates by presence of C. retropictus. 2016 to 2018 database of “Survey and Assessment of Estuary Ecosystem Health” by the Ministry of Environment were used to identify the distribution site of C. retropictus. The occupancy model was applied to estimate the potential habitat of C. retropictus. Four diversity indices were used to confirm the community structure of benthic macroinvertebrates. C. retropictus was found in the southern coast area and part of the east coast, and this pattern was consistent with previous studies. Additionally, the occupancy model predicted that a potential habitat of C. retropictus could appear in the west coast area. The community structure of benthic macroinvertebrates was relatively high at the site with C. retropictus than the site without C. retropictus. Therefore, the occupancy model can be considered when conserving C. retropictus inhabiting a limited area. Additionally, C. retropictus can be used to the indicator species that can represent the brackish water environment.

The Bayesian algorithm model is a model algorithm that calculates probabilities based on input data and is mainly used for complex disasters, water quality management, the ecological structure between living things or living-non-living factors. In this study, we analyzed the main factors affected Korean Estuary Trophic Diatom Index (KETDI) change based on the Bayesian network analysis using the diatom community and physicochemical factors in the domestic estuarine aquatic ecosystem. For Bayesian analysis, estuarine diatom habitat data and estuarine aquatic diatom health (2008~2019) data were used. Data were classified into habitat, physical, chemical, and biological factors. Each data was input to the Bayesian network model (GeNIE model) and performed estuary aquatic network analysis along with the nationwide and each coast. From 2008 to 2019, a total of 625 taxa of diatoms were identified, consisting of 2 orders, 5 suborders, 18 families, 141 genera, 595 species, 29 varieties, and 1 species. Nitzschia inconspicua had the highest cumulative cell density, followed by Nitzschia palea, Pseudostaurosira elliptica and Achnanthidium minutissimum. As a result of analyzing the ecological network of diatom health assessment in the estuary ecosystem using the Bayesian network model, the biological factor was the most sensitive factor influencing the health assessment score was. In contrast, the habitat and physicochemical factors had relatively low sensitivity. The most sensitive taxa of diatoms to the assessment of estuarine aquatic health were Nitzschia inconspicua, N. fonticola, Achnanthes convergens, and Pseudostaurosira elliptica. In addition, the ratio of industrial area and cattle shed near the habitat was sensitively linked to the health assessment. The major taxa sensitive to diatom health evaluation differed according to coast. Bayesian network analysis was useful to identify major variables including diatom taxa affecting aquatic health even in complex ecological structures such as estuary ecosystems. In addition, it is possible to identify the restoration target accurately when restoring the consequently damaged estuary aquatic ecosystem.

Fish assemblage of total 325 of Korean peninsula estuaries were surveyed to analyze the characteristics of community structure and diversity by sea areas for three years from 2016 to 2018. The scale (stream width) of Korean estuaries were various (14~3,356 m), and 68.9% of all estuaries showed salinity of less than 2 psu. Total 149 species classified into 52 families of fish were identified, and the dominant and sub-dominant species were Tribolodon hakonensis (relative abundance, RA, 12.5%) and Mugil cephalus (RA, 9.5%), respectively. The estuary of the Korean Peninsula had different physical and chemical habitat environments depending on the sea area, and accordingly, fish community structure also showed statistically significant differences (PERMANOVA, Pseudo-F=26.69, P=0.001). In addition, the NMDS (nonmetric multidimensional scaling) results showed the patterns that indicating fish community difference by sea areas, even though low community similarity within sea area (SIMPER, 21.79~26.39%). The estuaries of east sea areas were distinguished from the others in the aspects of which, the higher importance of migratory fishes and endangered species, and that of brackish species were characterized at south sea estuaries. However, the estuaries of west sea showed higher importance of species that have a relation with freshwater (primary freshwater species, exotic species), which is the result that associating with the lower salinity of west sea estuaries because of the high ratio of closed estuaries (78.2%). The SIMPER analysis, scoring the contribution rates of species to community similarity, also showed results corresponding to the tendency of different fish community structures according to each sea area. So far, In Korea, most studies on fish communities in estuaries have been conducted in a single estuary unit, which made it difficult to understand the characteristics of estuaries at the national level, which are prerequisite for policy establishment. In present study, we are providing fish community structure characteristics of Korean estuaries in a national scale, including diversity index, habitat salinity ranges of major species, distribution of migratory species. We are expecting that our results could be utilized as baseline information for establishing management policies or further study of Korean estuaries.

This study analyzed the relationship between the community structure of benthic macroinvertebrates and habitat changes in open estuaries among the sites included in the national estuary monitoring program. The estuary survey was conducted under the “Guidelines for Investigation and Evaluation of Biometric Networks” and classified by sea area, 80 places in the East Sea, 102 places in the South Sea, and 19 places in the West Sea were investigated. In a total of 201 open estuaries, benthic macroinvertebrates were identified with 4 phyla, 9 classes, 41 orders, 139 families, 269 species and 196 species in the East Sea, 182 species in the South Sea, and 90 species in the West Sea. The highest population densities were Insecta in the East Sea, the Malacostraca in the South Sea, and the Annelida in the West Sea. Through SIMPER analysis, species contributing to the similarity of benthic macroinvertebrates communities in each sea area were identified. Some species greatly influenced the similarity of clusters. The benthic community in the East Sea was affected by the salinity, so the contribution rate of freshwater species was high. On the other hand, the benthic communities of the South and West Seas showed species compositions are influenced by the substrate composition. As results, the benthic macroinvertebrate community in Korean estuaries was impacted by salinity and substrate simultaneously, and the close relationship with geographical distance was not observed. The result of this study is expected to be used to respond to environmental changes by identifying and predicting changes in the diversity and distribution of benthic macroinvertebrates in Korea estuaries.

An estuary is an area where a freshwater river or stream meets the ocean. Even before the importance of the value of estuaries was recognized, the estuary was lost because of large-scale conversion by draining, filling, damming, and dredging. In South Korea, 643 estuaries are located, and the total area is 3,248,300 ha, accounting for 32.5% of the total area of South Korea. Over 35% of Korean estuaries are closed estuaries which are only temporally connected with the sea, either permanently or periodically. Since 2008, in order to preserve the estuary ecosystem and solve major issues in the estuary by accumulating knowledge about the estuarine ecosystem, the Ministry of Environment of Republic of Korea has been conducting the “Estuarine Ecosystem Monitoring and Assessment Project”. At 668 sites of 325 estuaries, epilithic diatom, benthic macroinvertebrate, fish, and vegetation are investigated, and the habitat condition of each site is evaluated using the newly developed biotic index. More than 100 researchers annually record 2,097 species of estuaries according to the standardized survey guidelines over the past 14 years and provide strictly managed data necessary for establishing estuaries conservation policies. As a result of bibliometric analysis of 1,195 research articles related to the monitoring and assessment of the estuarine ecosystem, research on pollutants such as heavy metals and sediment control have recently been conducted. “Estuarine Ecosystem Monitoring and Assessment Project” is an ecological monitoring type of long-term mandated monitoring that is usually focused on identifying trends. Although it is difficult to identify the mechanism influencing a change in an ecosystem through long-term mandated monitoring, providing empirical data for supporting evidence-based policy, decision-making, and the management of ecosystems. In order to increase the efficiency of the project, research to investigate the relationship between sediments and pollutants and organisms can be conducted at specific estuaries or sites to compensate for the shortcomings of mandatory monitoring.

본 연구는 훼손된 하천 수생태계의 훼손원인을 식별하고 그 전이 과정을 규명하기 위해 수생태계 훼손원인 진단체계를 구축하고 정책적 활용 가능성을 보고자 하였다. 수생태계 현황 조사 및 건강성 평가결과는 하천의 훼손에 대한 전반적인 상황을 알 수 있어 하천 복원 및 관리의 판단 근거로 사용된다. 그러나 하천이 훼손된 원인이나 훼손이 발생하게 된 전이 과정을 고려하지 못한다는 한계를 가진다. 따라서 본 연구에서는 과학적이고 체계적인 진단체계를 제안하여 훼손원인과 그 전이 과정을 규명하였다. 미국, 호주, 유럽의 사례를 분석하여 우리나라에 맞는 진단체계를 제안하였다. 총 8단계로 구성되며, 기초자료 조사, 하천 수생태계 훼손 판단, 훼손 구간 설정, 훼손 유형화 및 잠재적 훼손원인 도출, 본 조사, 주 훼손원인 진단 및 최적 훼손 모델 도출, 종합분석 및 하천 복원방안으로 이루어져 있다. 이러한 진단체계는 하천 생태계의 복잡하고 다양한 특성을 고려하여 훼손원인을 파악할 수 있으며 하천 복원 및 관리 방안을 제시하여 효율적인 의사결정을 지원할 수 있다.

수생태계 생물학적 온전성을 평가하기 위하여 국내 하천 및 하구 923개 지점의 자료를 근거로 한국형 다중형 돌말지수 (KMDI)를 개발하고, 이를 금강수계 233개 지점을 대상으로 온전성평가를 실시하여 단일형 돌말지수들과 비교 검토하였다. KMDI의 개발은 1) 먼저 선행문헌들을 참고로 300개 이상의 메트릭을 추출하고, 2) 이 중 설명력이 높은 46개 후보 메트릭을 선택하며, 3) 각 메트릭 값들의 변이성, 중복성, 변별력, 환경에 대한 민감성 등을 검증하고, 최종적으로 5가지의 메트릭을 선정하였다. KMDI는 매트릭의 단순합으로 표현하고, 환경요인들에 대한 신뢰성 검토 결과, 토지이용, BOD, TN, 전기전도도 등에 대해 높은 민감성 및 설명력을 보였으나 단일형 돌말지수들 보다는 동일 지점의 생물학적 온전성은 다소 높게 평가되는 특성을 보였다. 추후 국내는 물론 지역에 상관없이 적용가능한 설명력 높은 매트릭의 발굴 및 정확한 돌말류 분석 연구가 뒷따라야 될 것으로 판단되었다.

한강수계 남한강의 보 (강천보, 여주보, 이포보) 공사 후 수변부 여울 구간의 물리적 환경의 변화에 따른 유수성 저서동물의 군집 변화를 확인한 결과 다음과 같은 결론을 얻었다. 첫째, 보에 의한 여울구간의 소실은 유속, 하상 등 물리적 환경의 변화를 야기하여 수질요인과는 독립적으로 수생태계에 영향을 미칠 수 있다. 둘째, 남한강 보 구간의 수변부 물리적 서식환경의 복합적인 변화는 유수성 분류군의 군집구성에 영향을 미친 것으로 판단된다. 셋째, 저서성 대형무척추동물 유수성 지표 후보종 157 분류군은 수생태계 변화의 원인 분석을 비롯한 하천 수생태계 복원 및 재자연화 등에 유용한 지표로 활용될 수 있을 것으로 기대된다. 넷째, 향후 유속변화에 대한 수생태계 영향을 면밀하게 파악하기 위해서는 분류군별 유속에 대한 저항성 또는 선호도를 바탕으로 한 지표연구가 필요할 것으로 사료된다.

With land-use (cover) and water quality, the distributional characteristics of epilithic diatom communities were studied with 193 samples from estuaries of Korean peninsula between 2015 and 2016. Of total 394 taxa classified, Nitzschia perminuta (19.6%) and N. inconspicua (14.0%) were the 1st and 2nd dominant species. Using a cluster analysis, the epilithic diatom communities of Korean estuaries were divided into four groups (G1-G4). Ecological characteristics of each group were followed: G1 was located in estuaries of the East Sea, and characterized by high forest land-use and high DO and low nutrients; G2 was the eastern part of the South Sea, and characterized by low turbidity and nutrients; G3 was the western part of the South Sea, and characterized by high agriculture, low electric conductivity and low salinity; G4 was the Yellow Sea, and characterized by high nutrients. The environmental factors having significant correlation with diatom distributions were as follows: TN to G1, turbidity to G2, agriculture to G3, and TP to G4. Moreover, the important factors affecting the occurrence of indicator species were forest land-use for Fragilaria construens var. venter in G1, turbidity for Rhoicosphenia abbreviata in G2, urban land- use and total phosphorus (TP) for Bacillaria paradoxa and Hantzschia amphioxys of G3, and TP and turbidity for N. ovalis and Stephanodiscus invistatus of G4. These results collectively indicate that the distribution of epilithic diatom communities in Korean peninsula was largely effected by water quality and land cover/use.

The aim of this study was to assess the interaction between Daphnia similis and various organisms related to the rice paddy ecosystem. We selected several organisms that are likely to prey on D. similis and evaluate predation rate as well as responses of D. similis to the chemical compounds exuded by these organisms. As a result of predation experiment, larval dragonfly (Anax parthenope) and Triops longicaudatus were clearly shown decreasing abundances of D. similis. Especially, Triops longicaudatus was observed higher feeding rates on D. similis than larval dragonfly. Chemical compounds from the vertebrates such as fish (Misgurnus anguillicaudatus, Pseudorasbora parva, Micropterus salmoides) and tadpole of frog (Rana nigromaculata) did not affect the life history of Daphnia. However, a potential predatory fish P. parva induced significantly longer tail spine in Daphnia. In addition, among the invertebrates (T. longicaudatus, A. Parthenope, Micronecta spp., Palaemon paucidens), chemical compounds exuded by T. longicaudatus induced shorter body and significantly longer tail spine in D. similis.

한반도 서남부 하천을 대상으로 2013년 5월(몬순의 영향이 없었던 시기)에 환경요인 및 부착돌말 군집을 각각 조사하였다. 조사는 상류에 1개 이상의 댐이나 인공 보가 형성된 조절하천(19개 지점)과 설치되어 있지 않은 비조절하천(19개 지점)으로 나누어 수질 및 부착돌 말 군집조사를 실시하였다. 조사결과, 부착돌말 출현특 성에 따라 한반도 서남부 하천은 비조절하천(G1), 혼합 형하천(G2), 조절하천(G3) 등 3개 유형으로 구분되었다. G1은 수질이 양호하고 다양한 부착돌말류가 출현한 반면, G3은 비록 수질은 불량하였으나 부착돌말 현존량 이 크게 증가하거나 감소하지 않았다. 또한 G2의 경우 조절하천에 비해 수질은 양호하였지만 부착돌말의 종수는 가장 낮게 나타났다. 본 조사에서 출현한 부착돌말 우 점종은 생태범위가 비교적 넓은 담수와 기수 보편종들로 서 G1에서 Nitzschia palea (17%), Navicula seminuloides (11%), G2에서 Nitzschia inconspicua (19%), Navicula perminuta (9%), G3에서 Nitzschia inconspicua (15%), Nitzschia palea (14%)으로 수질환경에 큰 영향을 보이지 않았으나 종수의 감소를 가져왔다. 그러나 G2와 G3 과 같은 조절하천에서 비록 부착돌말 현존량은 높지 않았으나 부영양 상태(높은 영양염 및 엽록소량 등)를 나타내 하구역의 정확한 수환경 상태파악을 위하여 국내 연안에서 종종 조류발생을 일으킬 수 있는 부유성 돌말 류에 대한 조사도 반드시 병행되어야 할 것으로 판단되었다.

한반도 동해안에 분포하는 대표적인 석호중의 하나인 화진포호에서 2010년 봄철(4~6월)에 돌말 Skeletonema costatum가 대발생하였다. 본 연구는 대발생기와 소멸기 동안 저수지의 식물플랑크톤 군집의 특성을 파악하고 수 질을 근거로 하는 호수의 영양지수를 산출하여 수질을 평가하였다. 분석결과 국내에서 가장 높은 세포밀도(¤105 cells mL-1)를 보였으며, 수온은 20􀆆C 전후였으나 더 높았 던 여름철(7월 이후)에는 소멸하였다. 저수지의 수질은 높은 염분도, BOD, COD, 인산염, 낮은 N/P비, 투명도 등 으로 부영양~과영양 상태로 나타났다. 식물플랑크톤 군 집은 돌말류가 높은 세포밀도를 보인 조류발생기 동안에 는 높은 우점도와 낮은 다양도를 보였으며, 소멸기에는 다시 회복되는 특성을 나타냈다. 결국 2010년 화진포호 의 Skeletonema costatum 대발생은 봄철 가뭄이 장기간 진행되고 하천수의 유입이 감소함으로써 비롯된 것으로 판단되며 매년 반복될 가능성을 시사해 주었다.

본 연구는 송천 상류지역의 고랭지 농업으로 인한 토사유입이 저서성 대형무척추동물에 미치는 영향을 알아보기 위하여 2006년부터 2009년에 걸쳐 실시되었다. 조사결과, pH, DO, EC, TDS, TN, TP는 하류로 갈수록 증가하는 경향을 보였으며, ORP는 감소하는 것으로 확인되었다. 특히 SS와 TP는 농경지 구간인 St. 2~St. 4에서 급격한 증가를 보였으며, 파종과 수확시기에 변화가 컸다. 저서성 대형무척추동물의 구성은 총 5문 6강 11

본 연구는 임하호 유역에 위치하는 반변천, 길안천과 낙동강에 총 8개 정점을 선정하여 2008년 9월부터 2009년 6월까지 물리-화학적 요인과 부착규조 군집과의 관계를 조사하였다. 부착 규조류는 총 120종류로서 2목, 3아목, 7과, 22속, 108종 및 12변종으로 구성되어 있다. 부착 규조 군집의 우점종은 Achnanthes alteragracillima, A. convergens, A. minutissima와 Fragilaria construe

본 논문에서는 하천생태계의 환경평가 기법과 생물다양성 관리시스템을 개발하여 한국의 하천에 적용한 사례를 소개하였다. 전국 하천에서 장기간 수집된 조사자료와 문헌자료 뿐만 아니라 북한강 수계의 일련의 하천들을 대상으로 종합적으로 실시한 야외조사를 바탕으로 하천생태계의 환경과 생물다양성에 대한 조사연구의 체계를 고찰하였고, 한국 하천의 주요 환경훼손 유형을 분류하였고, 하천자연도등급 간이평가표를 작성하여 제시하였으며, GIS를 적용한 하천생태계의 생물다양성