River health assessment using macroinvertebrates and water quality parameters: A case of the Shanbeh-Bazar River, Anzali Wetland, Iran

The study of benthic macroinvertebrate communities is one of the most common methods for assessing the effects of stresses on the biological conditions of aquatic ecosystems and water quality monitoring. This research was conducted to study the changes in the macroinvertebrate communities in the Shanbeh-Bazar River, Anzali International wetland and the effects of environmental factors. Sampling was done seasonally from spring to winter in 2017 from the. Bio-indicators, MDS, PCA, correlation and ANOSIM were used in this study. A total of 3963 macroinvertebrate belonging to 3 phyla, 9 orders of 17 families were identified. The two families of Chironomidae and Tubificidae were the most abundant, and the dominant group of the Shanbeh-Bazar River. The bio-indicators analysis varied from medium pollution to heavy pollution at different stations. MDS plot showed that sampling stations were clearly separated into 3 groups. ANOSIM and PCA analysis were shown that the human activities and urban wastewater effects on benthic communities such as increasing the resistant families (Tubificidae). The increasing of agricultural activities and the destruction of marginal forests at Stations 3 and 4 were caused the abundance of Chironomidae and Tubificidae increased. Since the Shanbeh-Bazar River has urban disturbance, especially wastewater inputs, agriculture, fishing and recreational boats, macroinvertebrate diversity decreased with increasing contaminants and stresses, led to an increase in resistant species. With the increase of agricultural and the destruction of marginal forests, the amount of organic matter increased in the water body. Anthropogenic activities are indicated to have the most negative effects on the river ecosystem. Thus, it was concluded that the river health of Shanbeh-Bazar River is within unacceptable range.