Intermediate disturbance hypothesis is one of important hypotheses for presenting the diversity patterns under disturbances. To investigate the diversity patterns of benthic macroinvertebrate communities under various disturbances, we collected macroinvertebrates in 47 sites representing various habitat types as well as pollution gradients in Southeastern Korea in summer and winter. Environmental variables such as depth, velocity, substrate and conductivity, and biological water quality indices (e.g., BWMP) were measured to show the intensity of disturbance in each site. Species abundance distributions (SADs) which are one of the efficient ways to assess community structure states based on macroecology were also considered to represent the pollution status based on the community patterns along an established pollution gradient. The community patterns were broadly divided into log-normal distribution and geometric series groups according to SAD models with weak and strong disturbance, respectively. According to the application of physicochemical water quality variable (conductivity), the gradient of community indices showed higher values on the intermediate disturbance state. Higher values of community indices, however, were presented on the low disturbance state with the gradient from BMWP. The parameters of SAD models, log-normal distribution, γ, and geometric series, k, were additionally calculated and compared with the traditional community indices.

• Dong-Hwan Kim(Department of Biology, Kyung Hee University)
• Young-Seuk Park(Department of Biology, Kyung Hee University)
• Tae-Soo Chon(Ecology and Future Research Association)