Long-Term Dynamics of Biological Diversity in Water Basins

The structural complexity of communities of living organisms can be assessed in various ways, including diversity indices. For these purposes, the Shannon index (H) was used in the present study. Based on the scarce available published data and our own data, the rates of changes in the number of species and complexity of the community structure of aquatic organisms were determined with reference to macrobenthos communities. The considered changes were described by equations of specific functions that were mathematically analyzed. It was suggested that, in a temperate climate and the absence of strong contamination or eutrophication of water bodies, 12–14 years on average are required for the formation of a complex structure (3–4 bits) of benthic animals under favorable conditions. The complex structure of communities formed in polluted waters remains rather constant. Longer studies (at least 20–30 years) than those used in the present work are necessary to verify and refine the above assumptions