摘要：Urbanization of catchment regions is a major cause of freshwater ecosystem degradation worldwide. As catchments become more developed and river ecosystems become increasingly engulfed in various land use activities, there is a growing need to understand these impacts on freshwater ecosystems. Macroinvertebrate are extensively used as indicators of ecosystem health and have been an instrument tool in ecosystem monitoring and management. Five stations with different types of land use (reference station, forest, recreational, agricultural, urban area) of Chehel Chai River, Iran were sampled in 2018. A total of 2040 macroinvertebrate belonging to 6 orders from 12 families were identified. The highest abundance was related to the diversity of the Ephemeroptera (Batidae). According to the results, the abundance of macroinvertebrate was significantly different in the seasons and sampling stations. The maximum value of diversity indices was measured to the Shannon index (S1= 1.06, autumn), Simpson's Index (S1= 0.63, autumn), Margalef richness (S1= 0.9, spring) and Pielou's index (S3= 0.92, summer). Stations in up-stream (forest area) recorded highest species richness, abundance and proportion of sensitive macroinvertebrates compared to the agricultural and urban development area. Cluster and nMDS analysis revealed that among the macroinvertebrates, Ephemeroptera were distinct in the forest sites and Diptera and Oligochaeta in urban area of Chehel Chai River. This finding suggests that present environment problem (such as: agriculture, tourism and urban area) caused serious impacts on the biodiversity of Chehel Chai River.
