Mountainous landscape vegetation and species composition at Wadi Helo: A protected area in Hajar Mountains, UAE

ABSTRACTWadi Helo (WH), in the United Arab Emirates, is a famous archeological site and protected area in the Hajar Mountains in the Arabian Peninsula. We investigated effects of topography, aspect, and altitude on floral diversity and species composition in this heterogeneous, mountainous, and highly arid environment. Using twenty transects distributed from the mountains top to the wadi bed; eighty plots, 100 m2 each, were selected for vegetation analysis. Classification of vegetation using TWINSPAN showed three groups in the wadi bed and five in the mountains, each distinguished by different dominant species. Forsskaolaea tenacissima, Rhazya stricta, Tephrosia apolina, Notoceras bicorne, Acacia tortilis, and Fagonia indica were dominants of the microhabitats of the wadi bed. Gorges were dominated with Dodonaea viscosa and Lavandula subnoda. The other four groups were found on the mountain slopes and were associated with particular aspects (being north-, south-, west-, or east-facing). The dominant speci...