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

The origin and maintenance of biological diversity have long been a central focus in ecology and evolution. The competitive exclusion principle states that the number of coexisting species is limited by the number of resources or by their similarity in resource use. However, natural systems such as the extreme diversity of unicellular life in the oceans provide counterexamples to this principle. Mathematical models incorporating population fluctuations can lead to violations of the exclusion principle, but it has not been clear how these fluctuations can contribute to increased diversity. In this study, published on arXiv, researchers Michael Doebeli, Eduardo Cancino Jaque, and Iaroslav Ispolatov use simple eco-evolutionary models to show that a certain type of population dynamics called "boom-bust" dynamics can allow for 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) followed by 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. The researchers used models that are extensions of classical competition models to high-dimensional continuous phenotype spaces. In previous work, they assumed that the underlying ecological dynamics have a stable equilibrium (the carrying capacity). However, they extended these models to allow for complicated ecological dynamics using difference equations rather than differential equations to describe ecological dynamics. They showed that for certain types of endogenously generated fluctuations termed "boom-bust" dynamics, the amount of diversity that evolves and is maintained at evolutionary steady state is much higher than what would be expected from stable equilibrium dynamics. Moreover, they found that chaotic boom-bust dynamics could also increase diversity in polar plankton communities where environmental conditions change rapidly over time. These findings suggest that boom-bust dynamics play an important role in the evolution and maintenance of biological diversity, particularly in environments where resources are limited or variable.

Exploring Boom-Bust Dynamics and the Maintenance of Biological Diversity

The origin and maintenance of biological diversity has long been a topic of great interest in ecology and evolution. The competitive exclusion principle states that the number of coexisting species is limited by resources or their similarity in resource use, yet natural systems such as the extreme diversity of unicellular life in the oceans provide counterexamples to this principle. In a recent study published on arXiv, researchers Michael Doebeli, Eduardo Cancino Jaque, and Iaroslav Ispolatov explore how population fluctuations can contribute to increased diversity through a type of population dynamics called "boom-bust" dynamics.

What are Boom-Bust Dynamics?

Boom-bust dynamics are characterized by long periods of almost exponential growth (boom) followed by a subsequent population crash due to competition (bust). This type of dynamic is thought to be an important factor in maintaining high levels of biodiversity as it allows for desynchronization between different species' boom-bust cycles which can lead to increased evolutionary diversification.

Modeling Boom-Bust Dynamics with Eco-Evolutionary Models

In order to test their hypothesis that boom-bust dynamics could increase biodiversity beyond what would be expected from stable equilibrium dynamics, Doebeli et al. used simple eco-evolutionary models incorporating difference equations rather than differential equations to describe ecological dynamics. These models were extensions of classical competition models but allowed for adaptive diversification in continuous phenotype spaces.

Results: Increased Biodiversity Through Boom Bust Cycles

The results showed that when boom bust cycles were incorporated into these eco evolutionary models, much higher levels of diversity were maintained at evolutionary steady state than what would be expected from stable equilibrium dynamics alone. Furthermore, they found that chaotic boom bust cycles could also increase diversity in polar plankton communities where environmental conditions change rapidly over time - suggesting that this type dynamic plays an important role in the evolution and maintenance of biological diversity particularly when resources are limited or variable.

Conclusion: Exploring New Avenues for Increasing Biodiversity

This research provides new insight into how fluctuations can contribute to increased biodiversity beyond what would be expected from traditional competitive exclusion principles alone - offering new avenues for exploring ways we might increase biodiversity both naturally and artificially going forward.