Wadi Ayaa occurs between latitudes 18º 57′ 24, 2″
North and longitudes 42º 31′ 16, 3″ East with
elevation 2100 - 1750 m (ASL). It lies in the upper
part of the Eastern slopping of Bellesmer Mountains
in the Southwestern region of Saudi Arabia. It
extends 50 km from Bahwan center in the South to
Wadi Bisha in the North. Underground water stream
of small, shallow river almost run all the year in the
middle of the valley, which represents the most
critical factor that determine the type of plant
communities. This is the first study, so far, to monitor
the plant species composition and the vegetation
cover of different communities occurring in Wadi
Ayaa. A maximum 53 plant species belonging to 24
families were collected and identified to distribute
among six plant communities dominated by Acacia
ssp., Zizyphus spina-Christi, Conyza incana, Tamarix
nilotica, Argemone ochroleuca, and Calotropus
procera. These six plant communities are showing to
cover three distinct types of vegetation sectors: ayaa
plateau, slope and valley according to altitude, habitat
factors and moisture availability.
Key words: Plant communities, Wadi Ayaa, Saudi Arabia
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