Inferring pollution states based on community structure of Benthic Macroinvertebrates in streams

Species abundance distributions (SADs) are an efficient means of assessing community structure to define macroecological states and ecological integrity in responding to environmental impacts. Rank abundance distributions of benthic macroinvertebrate communities collected from streams with different levels of pollution in Korea were obtained and used to confirm water quality classification based on empirical assessment. The pollution states were broadly divided into weak and strong pollution groups according to SAD models, log-normal distribution and geometric series, respectively. A lower gamma value in the log-normal distribution also differentiated weak pollution from strong pollution. Lower coefficient variation in the SAD slopes was further suitable in dividing less and slightly polluted states within the weak pollution group. Within the strong pollution group, a mixture of log-normal distribution to geometric series separated, polluted and severely polluted states. Higher correlation coefficients were observed between gamma and other water quality parameters, as well as community and biological water quality indices. Similar patterns in SADs were presented between spring and fall; however, gamma values of the less polluted state differed between seasons. Overall, developing SADs of related parameters is an efficient method of addressing ecological integrity that could serve as a reference system describing anthropogenic impact in streams.