| Abstract: | The present study analyses the vegetation of canals and drains in the Nile Delta in relation to environmental factors. 30 clusters were generated by the TWINSPAN technique. A DC A (DECORANA) ordination revealed a moisture gradient, and, less clearly, a salinity and a fertility gradient. The resultant clusters were assigned to seven vegetation types arranged according to moisture preference as follows: Imperata cylindrica - Desmostachya bipinnata, Phragmites australis, Panicum repens - Cynodon dactylon, Echinochloa stagninum - Polygonum salicifolium, Echinochloa stagninum, Eichhornia crassipes, and Ceratophyllum demersum-Pótame geton crispas. Their species diversity is discussed in view of the disturbance and heterogeneity hypotheses. |
