Extinction threshold and large population limit of a plant metapopulation model with recurrent extinction events and a seed bank component

TL;DR

This paper introduces a novel plant metapopulation model incorporating seed banks and recurrent extinctions, identifying an extinction threshold and linking individual-based dynamics to classical occupancy models.

Contribution

It presents a new intermediate model with 'ghost' individuals, analyzes extinction thresholds, and demonstrates convergence to stochastic patch occupancy models.

Findings

Existence of an extinction threshold for 'real' individuals.

Seed bank characteristics influence the extinction threshold.

Model converges to a SPOM under scaling.

Abstract

We introduce a new model for plant metapopulations with a seed bank component, living in a fragmented environment in which local extinction events are frequent. This model is an intermediate between population dynamics models with a seed bank component, based on the classical Wright-Fisher model, and Stochastic Patch Occupancy Models (SPOMs) used in metapopulation ecology. Its main feature is the use of "ghost" individuals, which can reproduce but with a very strong selective disadvantage against "real" individuals, to artificially ensure a constant population size. We show the existence of an extinction threshold above which persistence of the subpopulation of "real" individuals is not possible, and investigate how the seed bank characteristics affect this extinction threshold. We also show the convergence of the model to a SPOM under an appropriate scaling, bridging the gap between individual-based models and occupancy models.