The dominant-egalitarian transition in species-rich communities

Abstract
Data availability
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Abstract

Diverse communities of competing species are generally characterized by substantial niche overlap and strongly stochastic dynamics. Abundance fluctuations are proportional to population size, so the dynamics of rare populations is slower. Hence, once a population becomes rare, its abundance gets stuck at low values. Here, we analyze the effect of this phenomenon on community structure. We identify two distinct phases: a dominance phase, in which a tiny number of species constitute most of the community, and an egalitarian phase, where it takes a finite fraction of all species to constitute most of the community. Using empirical data from microbial, planktonic, and macroorganismal systems, we demonstrate the relevance of this transition and show how demographic stochasticity and immigration critically determine phase behavior. Our results suggest that even slight changes in noise strength or immigration rates can lead to abrupt shifts in community diversity.

Data availability

The current manuscript is a computational study, so no data have been generated for this manuscript. The simulation code has been deposited on GitHub, as indicated in the manuscript. The data analyzed was obtained from presvious published works, as indicated in the References

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https://www.pnas.org/doi/suppl/10.1073/pnas.2023170118/suppl_file/pnas.2023170118.sd01.xlsx

Article and author information

Author details

David A Kessler

Department of Physics, Bar-Ilan University, Ramat-Gan, Israel

For correspondence
David.Kessler@biu.ac.il

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-5279-1655
Nadav M Shnerb

Department of Physics, Bar-Ilan University, Ramat-Gan, Israel

For correspondence
nadav.shnerb@gmail.com

Competing interests
The authors declare that no competing interests exist.

Funding

Israeli Ministry of Innovation, Science and Technology (Israel-Italy Cooperation Program)

Nadav M Shnerb

Israel Science Foundation (1614/21)

Nadav M Shnerb

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are credited.