Application of additive partitioning to study the effect of aspect and elevation on alpha, beta and gamma diversities of plant species (case study: protected area of Geno, Hormozgan province)

This research was aimed to study the effects of elevation and aspect on diversity components (alpha, beta and gamma) using additive partitioning in the Geno Mountain. All plant species were listed in nine elevation zones (400-1050 m a.s.l.) in southern and eastern aspects of Geno. The cover percentage was measured using five plots of 4m2 (in total 90 plots) in each elevation zone. Total plant species diversity (γr) was partitioned into additive components within plots (α1) and between plots (β1) and among elevation zones (β2) and among aspects (β3). The results showed that β3 diversity (72.36%) and β1 (8.19%) had the highest and lowest contribution to the total diversity (γr), respectively. The β3 and α1 values were higher and lower than the expected values, respectively, indicating the non-random distribution of plant species. The lowest observed percentage and expected values at the alpha level were recorded for both southern and eastern directions. In addition, the lowest observed values at the alpha level were recorded for the southern (5.95%) and eastern (5.73%) directions. Generally, beta components had a higher percentage, whose values were higher than that of the expected values. On the other hand, the alpha component in eastern and southern directions was lower than expected values. The results showed that the highest Shannon index (1.72) and richness (22) were obtained at elevations of 1200-1600 m a.s.l. and 1600-2050 m a.s.l, respectively.According to the results of this study, it is suggested that the regional scale (whole area) should be taken into consideration to protect and enhance the diversity.