Plant distribution and diversity along altitudinal gradient of Sarrawat Mountains at Taif Province, Saudi Arabia

The present study aims at investigating the floristic diversity and distribution pattern of plant species along the elevation gradients of Sarrawat Mountain at Taif, Saudi Arabia. Three hundred and fifty-eight stands were selected along various elevation levels (I: less than 1000 m, II: 1000-1300 m, III: 13001600, IV: 1600-1900, V: 1900-2200, and VI: more than 2200 m above sea level) to represent the vegetation physiognomy on the study area. There were 573 species belonging to 297 genera and 73 families was recorded at elevation 1900-2200 ma.s.l, while the lowest number was recorded at elevation < 1000 ma.s.l. Based on the floristic composition along the different elevations, the agglomerative clustering technique recognised three clusters: A) comprised > 1000 and 1000-1300 m elevation levels; B) included 1300-1600 m and 1600-1900 m levels; and C) comprised 1900-2200 m and > 2200 ma.s.l. Asteraceae was the most dominant family, followed by Poaceae and Fabaceae. The life form spectra and chorotype of the recorded species indicated the predominance of chamaephytes and mono-regionals, respectively. Ten species, representing 9.4% of the total endemic species in Saudi Arabia, were recorded as endemic taxa. About 77.7% of the total species were used for grazing, while 58.6% were medicinal. The species diversity of the recorded species had its highest values at 19002200 ma.s.l, while the lowest were recorded below 1000 m. The present study provides a keystone for biodiversity and conservation of important plant areas of Saudi Arabia.