Health evaluation of riverine ecosystems using aquatic macroinvertebrates: a case study of the Mohammad-Abad River, Iran

Macroinvertebrates can provide an integrated picture of environmental changes. Health of rivers can be assessed based on measured changes in the ecological structure of macroinvertebrates. Using aquatic macroinvertebrates, we evaluated health of Mohammad-Abad River located in Golestan Province of Iran. Twelve sampling stations were selected along the river. Macroinvertebrates were sampled, and physicochemical parameters were measured at the same time. Twenty-seven families of macroinvertebrates were identified. They belonged to 6 orders of macroinvertebrates, Diptera with 86.82%, and had the highest frequency. Odonata (0.4%) had the lowest frequency. Canonical correlation analysis (CCA) indicates importance of nutrients in the distribution of different macroinvertebrates. Seventy-three percent of the variance in CCA was explained by nutrients and water temperature. Iranian Water Quality Index for Surface Water Resources Conventional (IRWQIsc) and Hilsenhoff Family-level Biotic Index (FBI), and biological monitoring working party/average score per taxon (BMWP/ASPT) consistently showed the same trend in our analyses. Our results showed high efficiency of water quality bio-evaluation for the river by measuring the macroinvertebrate communities, so that the results of the biological indices are consistent with the water quality index. Our method improves the costly, time-consuming and polluting methods that have been used in the past. Additionally, environmental changes due to a variety of land uses are better illustrated by our improved method. We conclude that FBI and BMWP/ASPT indices are suitable for assessing river health by macroinvertebrates.