Spatial and temporal changes of the benthic invertebrate's composition in the North part of the main drainage channel.

Abstract

The effect spatial and temporal changes of benthic invertebrate's composition were studied in two selected sites, before and after north part of Main Drainage Channel meeting within drainage canals of Abu-Grabe, Al-Rhedwania and Al-Yosfiaa. Monthly samples were collected from September 2001 to August 2002. Water temperature ranged between 10 in January to 29.5 C in August. Salinity concentration and water turbidity recorded lowest mean values (3.4 gm/l and 8.8 NTU respectively) in the first site, whereas, highest values was (6.2 gm/l and 30.0 NTU respectively) in the second site. Dissolved Oxygen has been shown highest mean values reached 7.3 mg/l in the first site; while, the lowest was recorded in the second site reached 3.9 mg/l. The present study classified 33 species of benthic invertebrates, aquatic insect larvae, oligochaetes and molluscs formed 18, 11 and 6 species, respectively, as well as one genus only of crustacean. Three benthic invertebrate species were found to be dominate, namely Chironomous sp. (Chironomidae), Pristina aequiseta (Naididae) and Cypris sp. (Ostracoda). A total invertebrates density were recorded lowest values (4110.7 indi/m2) and highest ones (4906.6 indo/m2) in the first and second sites respectively. The highest values of total invertebrates density represented by oligochaetes and crustacean (3979.1 and 590.8 indi/m2 respectively) in the second site. A total biodiversity values in the Main Drain Channel reached 1.8 and 2.6 in the first and second sites respectively. The present study showed increasing in total density and biodiversity of benthic invertebrates in the second site of the north part of Main Drainage Channel after meeting within drainage canals of Abu- Grabe, Al-Rhedwania and Al-Yosfiaa.