Study of seasonal distribution of chironominae (Chironomidae: Diptera) in Al- Battar river north Al Kut city / Iraq.

Abstract

The influence of physical and chemical parameters on the abundance and diversity of subfamily Chironominae(Chironomidae: Diptera) in Al-Battar river north Al-kut city was studied over a period of eight months(Septemper 2012- April 2013) . Eight species of Chironominae were identified Chironomus plumosus (Linnaeus) was the most dominant made up 42.5% ,Chironomus sp. 17.8% ,Einfeldia sp. 13.6%, Chironomus riparius Meigen 10.3%,Chironomus staegeri Lundbeck 10.3%, Lauterborniella sp. 2.6% ,Parachironomus sp. 1.4% and Parachironomus hirtalatus(Beck & Beck) 1.1%. The results of this study showed that were significant correlations between the species and several environmental parameters.C. plumosus, C.staegeri, C.riparius and Einfeldia sp. this group showed significantly positive correlation ( p<0.01 and 0.05) with water depth and NH4-N and showed significantly negative correlation( p<0.01 and 0.05) with water turbidity. Also this group showed negative correlation but not significant with water temperature and NO3-N. C.plumosus showed positive correlation but non significantly with (pH, EC,TDS and NaCL) and showed no significant negative correlation with DO. One species Parachironomus sp. showed significant positive correlation with pH, EC, TDS and NaCL and this species recorded only in September. Parachironomus hirtalatus showed significant negative correlation with water depth and NO3-N. Lauterborniella sp. showed significant positive correlation with dissolved oxygen. Also showed positive correlation but non significantly with temperature, NO3-N, NH4-N, EC, TDS and NaCL and negative correlation but non significantly with pH, turbidity and water depth .Chironomus sp. showed positive and negative correlation but non significantly with ecological factors, so showed positive correlation with EC, TDS, NaCL, water depth and temperature. This species showed negative correlation with pH, DO, turbidity, NO3-N and NH4-N.