Bet-hedging against demographic fluctuations

TL;DR

This paper demonstrates that bet-hedging strategies, involving diversification into subpopulations with different growth and survival traits, can effectively mitigate demographic fluctuations and optimize long-term population abundance.

Contribution

It introduces a generalized model that unifies bet-hedging strategies against both environmental and demographic uncertainties in population dynamics.

Findings

Diversification into fast-growing and better-surviving subpopulations enhances long-term abundance.

The model incorporates dispersal and local environmental variations.

Bet-hedging is effective even in constant environments against demographic fluctuations.

Abstract

Biological organisms have to cope with stochastic variations in both the external environment and the internal population dynamics. Theoretical studies and laboratory experiments suggest that population diversification could be an effective bet-hedging strategy for adaptation to varying environments. Here we show that bet-hedging can also be effective against demographic fluctuations that pose a trade-off between growth and survival for populations even in a constant environment. A species can maximize its overall abundance in the long term by diversifying into coexisting subpopulations of both "fast-growing" and "better-surviving" individuals. Our model generalizes statistical physics models of birth-death processes to incorporate dispersal, during which new populations are founded, and can further incorporate variations of local environments. In this way we unify different bet-hedging strategies against demographic and environmental variations as a general means of adaptation to both types of uncertainties in population growth.