Ruben Taieb : Dormancy: a trade-off between resilience and invasiveness, an ODE and reaction-diffusion model

Dormancy, whether in ecology, bacteriology or cell dynamics, is a reversible reduction of metabolic activity reducing resource consumption and increasing resistance against exterior pressure. We first consider a simple bistable ODE equation to model how dormancy affects survival of a population after either a catastrophic event or after arrival in a new environment. We observe the classical result that dormancy protects a species against uncertain environments and catastrophic events, but we also notice that dormancy strengthens the Allee effect, effectively reducing invasiveness and increasing the inertia of the environment. We then present a bistable coupled ODE-reaction diffusion model for dormancy and Go-or-Grow, and prove the sharp (or non-sharp for some Go-or Grow dynamics) threshold property. Studying its variation with respect to system parameters, we see how the resilience-invasiveness trade-off inherent to dormancy affects the spatial dynamics and survival of a species. We also investigate properties on the optimal strategy for dormancy or reactivation to minimize the survival threshold.