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.

Abstract
서 론
재료 및 방 법
    1. 하구 수생태 생물상 및 수질 데이터
    2. 생물 다양성 산출과 비교
    3. 생물 다양성 지수와 환경 요인 간 상관관계 분석
결 과
    1. 하구 유형에 따른 분류군별 지점에 따른 α-다양성 변화경향
    2. 하구 유형에 따른 분류군별 γ-다양성 특성
    3. 하구 유형에 따른 분류군별 β-다양성 특성
    4. 하구 유형 및 분류군별 각 지점의 β-다양성 기여도 비교
고 찰
적 요
REFERENCES

• 오혜지(경희대학교 환경학및환경공학과) | Hye-Ji Oh (Department of Environmental Science and Engineering, Kyung Hee University) Corresponding author
• 장민호(공주대학교 생물교육과) | Min-Ho Jang (1Department of Biology Education, Kongju National University)
• 김정희(주식회사 에코리서치) | Jeong-Hui Kim (EcoResearch Incorporated)
• 김용재(대진대학교 생명과학과) | Yong-Jae Kim (Department of Life Science, Daejin University)
• 임성호((주)생태조사단 부 설 두희생태연구소, 공주대학교 생명과학과) | Sung-Ho Lim (Doohee Institute of Ecological Research, Korea Ecosystem Service Inc, Department of Biological Sciences, Kongju National University)
• 원두희((주)생태조사단 부 설 두희생태연구소) | Doo-Hee Won (Doohee Institute of Ecological Research, Korea Ecosystem Service Inc)
• 문정숙(국립환경과학원 물환경공학연구과) | Jeong-Suk Moon (Water Environmental Engineering Research Division, National Institute of Environmental Research)
• 권순현(국립환경과학원 물환경공학연구과) | Soonhyun Kwon (Water Environmental Engineering Research Division, National Institute of Environmental Research)
• 장광현(경희대학교 환경학및환경공학과) | Kwang-Hyeon Chang (Department of Environmental Science and Engineering, Kyung Hee University) Corresponding author