macrozoobenthos communities structure in the upper tributaries of the timiŞ river (south-west of romania)

In 2009, it was studied the structure of macrozoobenthic communities from the tributaries of the upper sector of Timis River, which partially drain three mountain ranges: Semenic, Tarcu and Poiana Rusca, these investigations being the first of this kind conducted in the South-Western part of Romania. Parallel with the investigation of the benthic communities, water samples were also taken and it was performed the determination of the following parameters: ph, conductivity, dissolved oxygen, total hardness, Ca, Mg, cyanide, nitrogen and total phosphorus, this waters being included in the first class category of the surface waters. The community of invertebrates of these tributaries is a complex community, made of 16-18 groups of benthic invertebrates, characteristics of clean watercourses, from the upper sector of a lotic system. The abundance of groups that indicate an excellent water quality (Ephemeroptera, Plecoptera, Trichoptera), differ depending the massifs mountain where these tributaries come from. Thereby, in tributaries that are from Tarcu, over 50% of benthic community is represented by these three groups (53%). This percentage drops to 42% for the tributaries that come from Poiana Rusca and reaches 22% for those that drain Semenic Mountain. All these results attest to tributaries of Timis River, situated in its upper sector, a river which can be included in a first class of surface water, taking into consideration both chemical parameters of water and the structure of the macronevertebrate benthic communities.