Abstract

The aim of the present study was to investigate biodiversity index, dominancy index and equivalence index of diatom community in the Tortum Stream and its tributaries. Diatom samples were collected from nine stations on the main river and tributaries between July 2012 and May 2013. A total of 36 taxa of Bacillariophyceae were identified. Dominant species was Cocconeis placentula in all stations. Biodiversity index was lower on the upstream river than downstream and tributaries. Not only domestic and agriculture pollution but also dam construction and stone pit affected Tortum Stream negatively. In conclusion, species richness decreased while organic pollution tolerant species increased.

Key words: Diatom, biodiversity index, dominant index, evenness index, Tortum Stream.