Methods Applied for Measurement and Visualization of Changes in Biodiversity

The article presents the possible methods for determining biological or statistically significant differences between taxocenoses compared with respect to biodiversity. To obtain a complete description of biological differences between the compared hypothetical communities, the following indices were calculated: S (taxon richness), H (the Shannon index), H_max (the maximum value of the Shannon index for the richness of taxa represented by the same number of individuals), V_d (a percentage value of covering the structural capacity of community, “evenness deficiency”), E (the MacArthur index - a taxon number (S) in a community for which the observed value of H equals H_max), and P_s (a taxon richness shortage in percents). Moreover, a graphic profile method (Дд, Tj, and Lj profiles) was used for comparing the diversity of the communities. To obtain information about statistically significant differences in biodiversity between the analysed communities, rarefaction curves were applied. The curves are based on the null models and the Monte Carlo method. The rarefaction method resulted in determination of the statistical significance of the differences between taxon richness and Shannon's index values for the compared communities. The V_d and P_s indices and the profile method allowed concluding about the significance of the biological differences between taxocenoses, even when their values of Shannon's H indices were numerically similar.