The study was conducted in Nif Stream (İzmir) and the aims of the study are (a) to determine the benthic macro-invertebrate composition of the stream, (b) to determine environmental features of the stream, (c) to investigate the relations between the determined species and the environmental variables and (d) to assess the trophic level of the stream which was under the pressure of industry, agriculture and settlement. Samplings of macrobenthic invertebrates were performed seasonally at eight stations between October 2013 and September 2014 in addition to measuring environmental variables of the localities. 11571 specimens were investigated and totally 77 taxa were determined. Chironomidae and Oligochaeta were the higher groups in terms of species richness with 25 and 17 species, respectively. Multivariate analyses indicate that pH, Ca 2+ and NO 3 -N were the most effective variables and explained 48.6% of the variance in the distribution and abundance of benthic macroinvertebrates in Nif Stream. Along the measured physicochemical characteristics and scores of biological indices, the upper branches of the stream have good quality water while the middle and lower parts are heavily polluted.

Although the Erfelek Stream is a small stream with a total length of 80 km and a flood discharge of 302.1 m 3 /sec, from its source to the place where it merges with the sea. It is ecologically very important for its immediate environment in terms of the zonations created by it and the groups of living organisms it contains. The fact that it is the only stream that reaches the sea by forming a delta between the Kızılırmak and Filyos Stream and that it reaches the sea by drawing meanders in the delta after different geological formations it passes through starting from an altitude of 1370 meters allows it to be a stream rich in biodiversity. Karagöl, which is connected with the sea, which is almost destroyed within the delta, and the Aksaz wetlands, which are still continuing their existence increase the importance of the stream in terms of both aquatic products and other groups of living organisms. In the fauna and flora of the Erfelek stream, the presence e few benthic invertebrate, fish, birds, mammals and plant species have been identified up to now. On this study, the importance of biodiversity and ecology of Erfelek Stream is aimed to be revealed as a result of present data and preliminary observations.