Habitat and plant communities in the Nile Delta of Egypt. II. Irrigation and drainage canal bank habitat.

The present study provides quantitative analysis of the vegetation and spatial variations of environmental factors controlling the abundance and distribution of vegetation in canal and drain banks in the Nile Delta region of Egypt. Five vegetation groups have been recognized: group A codominated by Arundo donax and Polygonum equisetiforme, group B codominated by Rumex dentatus and Polypogon monspeliensis, group C dominated by Eichhornia crassipes, group D codominated by Phragmites australis and Echinochloa stagnina and group E dominated by Typha domingensis. The total number of weeds recorded in the study area is 113 species belonging to 36 families. Therophytes (48.67%) and geophytes (14.16%) are the most frequent life-forms. The major chorotypes in the study area are Mediterranean (42.48%), Cosmpolitan (19.47%), Pantropical (13.27%) and Palaeotropical (12.39%). The relationships between the vegetation gradients and edaphic factors showed that, potassium and sodium cations, potassium adsorption ratio, chlorides, sodium cation adsorption ratio, pH value and water-holding capacity are the main controlling edaphic factors.