Plant community distribution and variation along the Awash river corridor in the main Ethiopian rift

The vegetation along the Awash River (1200-km long) in the main Ethiopian Rift, and its relationship with environmental factors was studied. Seven plant communities were described from the study area: (1) Acacia nilotica subsp. leiocarpa. - Carissa edulis type; (2) Acacia robusta subsp. usambarensis - Acokanthera schimperi type; (3) Celtis africana - Mimusops laurifolia type; (4) Acacia senegal - Acacia mellifera - Dobera glabra type; (5) Acacia nilotica subsp. indica - Ficus capreaefolia type; (6) Lannea schimperi-Glycine wightii type; and (7) Tamarix nilotica - Acacia hocki community type. It has been shown that the plant communities along the river follow an altitudinal gradient. The vegetation of the Awash River is mainly the result of the interactions between edaphic factors, the hydrology, altitude, slope and climate.