Abstract
The present study aimed to investigate the dominance of perennial plant communities in Rawdhat Al Masodi in Saudi Arabia and the effect of soil physical and chemical variables on the species distribution. A total of 51 plant species representing 25 families were reported from the study site in which 19 perennial species were reported that composite 7 plant communities. The soil physical and chemical variables showed significant differences among plant communities (ANOVA, p<0.05) except for pH. The identified plant communities (C1-C7) were dominated by Rhazya stricta, Calotropis procera, Acacia gerrardii, Acacia ehrenbergiana, Pulicaria undulate, Zilla spinosa and Teucrium oliverianum, respectively. The CCA model between species composition and soil physical and chemical variables was significant (Monte-Carlo test, 499 permutations, p<0.05) and explained 51.15 % of the total variation in species composition. The CCA identified strong factors structuring the perennial plant species in Rawdhat Al Masodisuch as organic matter (OM), total dissolved salts (TDS), phosphate (PO4), carbonate (CO3) and bicarbonate (HCO3) contents. In conclusion, there was remarkable diversity in plant communities in Rawdhat Al Masodi with remarkable variation in their physical and chemical properties of soil. The floristic diversity in this area is threatened by several factors including occasional recreational activities, woodcutting and development. Further ecological studies should be conducted to better understanding the factors influencing the plant community in this area. The government should design immediate and effective conservation programs to protect the floristic diversity in this area from future deterioration.