The Response of Benthic Community to Son1e Ecological Factors in Wadi El-Rayan lakes (EI-Fayoum)

Abstract

Wadi EI-Rayan (30 23' E and 20 68' N) is a small depression located east of the Western Desert, Wadi EI-Rayan is one of the most arid regions of the world. Wadi EI-Rayan was designated a Protected Area in 1989 to protect the area's unique biological, geological and natural cultural resources. The Protected Area covers an area of 1759 km2 in the southwestern part of the EI-Fayoum

Governorate, and comprises a diversity of habitats, each with its own characteristic wildlife and features.

The two lakes of Wadi EI-Rayan are man-made wetland formed in 1973 when a desert depression was inundated with excess agricultural drainage water. The total area of the upper and the lower lakes is about 110 km2 , divided into 52.5 km2 and 57.5 km2 for the upper and lower lake; respectively. The upper lake is completely filled with water with a maximum depth of about 25 m and the lower one has a maximum depth of about 30 m where the level is changing with time Extensive reedbeds have formed along the shoreline creating vital breeding ground for fish and water birds. The creation of a large body of water in this hyper-arid area had a striking ecological impact: new species of plants, mammals, birds and invertebrates (especially Bottom fauna plays an important role in aquatic food chain, also as natural diet for many fishes) moved to Wadi El Rayan area.