Spatial populations with seed-banks in random environment: III. Convergence towards mono-type equilibrium

TL;DR

This paper studies the convergence to mono-type equilibrium in a spatial Moran model with seed-banks in a random environment, identifying conditions for fixation and analyzing the influence of migration and environment on population dynamics.

Contribution

It characterizes the domain of attraction for mono-type equilibria and proves convergence to fixation in recurrent migration kernels within a random environment.

Findings

System converges to mono-type equilibrium under recurrent migration.

Fixation probability is independent of environment for almost all realizations.

Provides a formula for fixation probability based on environment-averaged densities.

Abstract

We consider the spatially inhomogeneous Moran model with seed-banks introduced in den Hollander and Nandan (2021). Populations comprising $active$ and $dormant$ individuals are structured in colonies labelled by $\mathbb{Z}^d,~d\geq 1$. The population sizes are drawn from an ergodic, translation-invariant, uniformly elliptic field that form a random environment. Individuals carry one of two types: $\heartsuit$, $\spadesuit$. Dormant individual resides in what is called a seed-bank. Active individuals exchange type from seed-bank of their own colony and resample type by choosing parent from the active populations according to a symmetric migration kernel. In den Hollander and Nandan (2021) by using a dual (an interacting coalescing particle system), we showed that the spatial system exhibits a dichotomy between $clustering$ (mono-type equilibrium) and $coexistence$ (multi-type equilibrium). In this paper we identify the domain of attraction for each mono-type equilibrium in the clustering regime for a $fixed$ environment. We also show that when the migration kernel is $recurrent$, for a.e. realization of the environment, the system with an initially $consistent$ type distribution converges weakly to a mono-type equilibrium in which the fixation probability to type-$\heartsuit$ configuration does not depend on the environment. A formula for the fixation probability is given in terms of an annealed average of type-$\heartsuit$ densities in dormant and active population biased by ratio of the two population sizes at the target colony. For the proofs, we use duality and environment seen by particle introduced in Dolgopyat and Goldsheid (2019) for RWRE on a strip. A spectral analysis of Markov operator yields quenched weak convergence of the environment process associated with single-particle dual to a reversible ergodic distribution which we transfer to the spatial system by using duality.