Tree Genetics and Molecular Breeding 2024, Vol.14, No.1, 8-11 http://genbreedpublisher.com/index.php/tgmb 9 Figure 1 Location of the 1 568 plots, tropical forest regions, and tropical forest biome extent used in the study Figure 2 Rarefaction curves showing the effect of increasing sample size on the number of hyperdominants, total species, hyperdominant percentage and fitted values of Fisher's α in tropical tree communities Table 1 presents a comparative analysis of tree species hyperdominance in tropical forests across Africa, Amazonia, and Southeast Asia, standardized to a common sample size of 77 587 trees. Africa has the lowest number of hyperdominants (77) and total species (1 132), whereas Amazonia exhibits the highest in both categories, with 174 hyperdominants and 2 656 total species. Southeast Asia is comparable to Amazonia in species richness but slightly less in hyperdominance. Hyperdominant percentages are fairly similar across regions, ranging from 6.79% in Africa to around 6.60% in Amazonia and 6.65% in Southeast Asia. Fisher's α, a diversity index, is notably higher in Amazonia (525) and Southeast Asia (526) compared to Africa (191), suggesting greater species diversity in the Amazonian and Southeast Asian forests relative to African forests at this sample size. Figure 3 depicts the dominance-diversity relationship in tropical forests of Amazonia, Africa, and Southeast Asia by showing the dominant proportion of total species required to account for various dominance thresholds (10% to 90%) of the total number of stems. The circles indicate data rarefied to the Southeast Asia dataset size, while diamonds represent extrapolated regional scale data. It shows that for a lower dominance threshold, a small percentage of total species is sufficient to account for the given percentage of stems. As the dominance threshold increases, the proportion of species required to meet the threshold also increases, with the highest variability observed at extreme dominance thresholds, particularly in the Amazon. The plot highlights notable differences in species dominance between rarefied and extrapolated data, suggesting that dominance patterns may differ significantly when projected across larger scales. This also underscores the variation in species dominance among different tropical regions, with Southeast Asia showing a narrower confidence interval, indicating more consistent results across samples.
RkJQdWJsaXNoZXIy MjQ4ODYzMg==