Effect of dominants on species richness of plant communities in the context of the energy hypothesis

We compared the participation of dominants, biomass, and the number of associated species in a series of biomass samples taken from 69 sites of terrestrial plant communities in the Western Caucasus and Ciscaucasia (high and low mountain meadows and steppes, communities of wastelands, old fallows, etc.), as well as seven sites of macrophytobenthos in the upper sublittoral of the Black and Azov Seas. The results showed that an increase in the participation of dominant species leads to a significant decrease in species richness in small areas of terrestrial communities, but does not have a significant effect on it in marine communities. At the same time, both in terrestrial and marine communities, similar biomass of associated species, selected in sites with different participation of dominants, includes a predominantly similar number of such species. This result can be considered as an argument for the validity of Wright's species-energy hypothesis. It also indicates that the relationship between biomass and the number of associated species is the main mechanism for the influence of dominants on the species richness of plant communities. This means that their effect on other species is predominantly indiscriminate. Accordingly, the size of the species pool of community sites with high and low participation of dominants should be approximately the same.