Annual Research & Review in Biology

The study aims at evaluating cyanobacterial diversity along altitudinal gradient with respect to various edaphic factors at western Saudi Arabia. Thirty-one cyanobacteria species belonging to 17 genera were isolated and identified along the different sites of the study area. Nostoc and Spirulina had the highest number of species in the study area (four species each), followed by Chroococcus and Oscillatoria (two species each). The number of colonies had positive correlation with organic matter and phosphates. The application of the two-way indicator species analysis  to the data set of the percentage presence of 31 cyanobacteria species in 40 stands resulted in agglomerating of 6 groups (communities) at 4^th level of classification. The application of the detrended correspondence analysis (DCA) indicates reasonable segregation between these groups .The application of CCA on the cyanobacteria communities and environmental variables indicated that some cyanobacteria species are correlated positively with total number of associated plants, TSS and phosphates such as Woella saccata Wolle, Chroococcus minor Lemm, Chroococcus majore Lemm, Microcystis areuginosa, Smith Anabaena spiroides Lemm  and Nostoc muscorum Agard, while others are negatively correlated with organic matter, chlorides, pH, EC, clay and silt such as Oscillatoria  limosa Bory, Synchococcus sp., Spirulina major Kutz and Lyngbya  borgertii Lemm. It is worthy to mentioned that, the soil samples dominated by Commicarpus sinaicus Meikle, Verbesina encelioides (Cav.) Benth &Hook. f. ex A. Gray, Argemone ochroleuca Sweet, Haloxylon salicornicum (Moq.) Boiss., Acacia tortolis (Forssk.) Galasso & Banfi and Morettia parviflora Boiss. had no cyanobacteria species.