الترکیب المجتمعی للافقاریات القاعیة فی نهر الزاب الکبیر / العراق

A study_ of macroinvertebrate community has been carried out at three sites selected on greater zab river included Qandel, Efraz and Khabat region. A total of 32 species of benthic invertebrates were recorded including Nematoda, Oligochaeta, Ostracoda, Decapoda, Insecta and Mollusca. During studied period the insecta were regarded the most dominated group, as they observed during all studied periods followed by Oligochaeta which observed in all studied sites. Shanon-Weiner index was used to reflect the effect of environmental fll..lctuation on benthic invertebrate communities, and the results showed that the species diversity of studied sites was ranged between 0.41 to 2049 bits/ind. in Qandel and Efraz regions respectively.