Abdullah M Al Qahtani
King Saud University, Saudi Arabia
Abdullah M Al Qahtani has completed his MSc and is currently pursuing his PhD in the College of Science, King Saud University, Riyadh.
Composition of plant species and vegetation types in Fiqra Mountains in Madinah, Saudi Arabia were studied. Plant and soil samples were collected from 100 different stands in the study sites. Collected plants were identified and their chorotypes and life forms were determined. Soil physical and chemical analyses were performed. Vegetation cover was analyzed using TWINSPAN and DECORANA software. A total of 126 species representing 39 families of vascular plants are recorded. Fabaceae, Poaceae and Boraginaceae are the largest families and therophytes and chamaephytes are the most frequent, indicating a typical desert life-form spectrum. The floristic composition of the different geomorphologic landscape units shows differences in species richness. The highest species richness value (23 species stand-1) is recorded in the Wadi bed. The lowest species richness value (18 species stand-1) is recorded in the Wadi plateau and fissures. Chorological analysis revealed that 52% of the studied species are bioregional, native to the Saharo-Arabian–Sudano-Zambezian region. After application of the TWINSPAN, DCA and CCA programs four vegetation groups were identified and they were named after the characteristic species as follows: (1) Aristolochia bracteolata-Cucumis prophetarum; (2) Calotropis procera-Acacia hamulosa-Caralluma russeliana; (3) Acacia abyssinica- Acacia hamulosa-Tephrosia desertorum; and (4) Argemone ochroleuca-Senna italica. The associations and speciation of these plants demonstrate significant variation in pH, electrical conductivity, soil mineral contents and human impact.