Boom-bust population dynamics can increase diversity in evolving competitive communities

TL;DR

This paper demonstrates that boom-bust population dynamics can promote higher biodiversity in competitive communities by desynchronizing cycles and allowing more species to coexist than traditional models predict.

Contribution

It introduces eco-evolutionary models showing how boom-bust dynamics enable greater diversity through cycle desynchronization, challenging the competitive exclusion principle.

Findings

Boom-bust dynamics facilitate coexistence of more species.

Desynchronization of cycles maintains high diversity.

Models violate traditional resource-based diversity limits.

Abstract

The processes and mechanisms underlying the origin and maintenance of biological diversity have long been of central importance in ecology and evolution. The competitive exclusion principle states that the number of coexisting species is limited by the number of resources, or by the species' similarity in resource use. Natural systems such as the extreme diversity of unicellular life in the oceans provide counter examples. It is known that mathematical models incorporating population fluctuations can lead to violations of the exclusion principle. Here we use simple eco-evolutionary models to show that a certain type of population dynamics, boom-bust dynamics, can allow for the evolution of much larger amounts of diversity than would be expected with stable equilibrium dynamics. Boom-bust dynamics are characterized by long periods of almost exponential growth (boom) and a subsequent population crash due to competition (bust). When such ecological dynamics are incorporated into an evolutionary model that allows for adaptive diversification in continuous phenotype spaces, desynchronization of the boom-bust cycles of coexisting species can lead to the maintenance of high levels of diversity.