Taxonomy of benthic macroinvertebrates in Jajrud River for water quality assessment

The invertebrates are one of the most important terrestrial fauna and freshwater taxa.Benthic macroinvertebrates include aquatic insects and spiders, mites, crustaceans, andspecies of mollusks and worms that are aquatic in their immature stages and terrestrial intheir adult stage. Jajrud River originates from the Alborz Mountains and is a source ofdrinking water for people in eastern part of Tehran and the surrounding villages. For thetaxonomic identification of benthic macroinvertebrates, five stations downstream of Jajrudwere used. A Surber sampler device was used for sampling with dimensions ۳۰ × ۳۰ cmand mesh size of ۲۵۰ microns in all four seasons of the year ۲۰۱۳ with three repetitions ateach station. In total, five orders (Ephemeroptera, Coleoptera, Diptera, Trichoptera, andOligochaeta) and ۱۳ families of benthic macroinvertebrates were identified. In all stations,the family Baetidae (Baetis sp .) belonging to the order Ephemeroptera had the highestabundance, and seasonally the highest abundance was detected in autumn, winter, summer,and spring respectively. After the identification of benthic macroinvertebrates, five bioticindices including EPT, HFBI, SIGNAL, NJIS, and MMIF were calculated for water qualityassessment in downstream of the Jajrud River. Regarding the results of the biotic indices, itcan be said that the water quality of downstream of Jajrud River is not favorable. Therefore,appropriate management measures should be taken to improve river water quality.