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.

Abstract
 1. 서 론
 2. 재료 및 방법
  2.1. 조사지점 및 조사기간
  2.2. 조사방법 및 저서성 대형무척추동물의 분류
  2.3. 생물지수 및 생물학적 수질지수
 3. 결과 및 고찰
  3.1. 저서성 대형무척추동물 구성의 변화
  3.2. 우점종과 EPT군의 구성변화
  3.3. 섭식기능군의 분포변화
  3.4. 생물지수와 생물학적 수질지수의 변화
 4. 결 론
 REFERENCES

• 김형곤(국립수산과학원 내수면양식연구센터) | Hyoung-Gon Kim (Inland Aquaculture Research Center, National Fisheries Research and Development Institute)
• 윤춘식(창원대학교 생물학 · 화학융합학부) | Chun-Sik Yoon (Department of Biology & Chemistry, Changwon National University)
• 정선우(창원대학교 생물학 · 화학융합학부) | Seon-Woo Cheong (Department of Biology & Chemistry, Changwon National University) Corresponding author