Uniform dispersion in growth models on homogeneous trees

TL;DR

This paper studies population survival on homogeneous trees under random catastrophes and uniform dispersal, providing bounds on survival probability, colonization, dispersion, and extinction time.

Contribution

It introduces a model of population dynamics with uniform dispersal on homogeneous trees, analyzing survival conditions and key probabilistic bounds.

Findings

Derived bounds for survival probability.

Estimated the number of colonized vertices.

Analyzed mean time to extinction.

Abstract

We consider the dynamics of a population spatially structured in colonies that are vulnerable to catastrophic events occurring at random times, which randomly reduce their population size and compel survivors to disperse to neighboring areas. The dispersion behavior of survivors is critically significant for the survival of the entire species. In this paper, we consider an uniform dispersion scheme, where all possible survivor groupings are equally probable. The aim of the survivors is to establish new colonies, with individuals who settle in empty sites potentially initiating a new colony by themselves. However, all other individuals succumb to the catastrophe. We consider the number of dispersal options for surviving individuals in the aftermath of a catastrophe to be a fixed value $d$ within the neighborhood. In this context, we conceptualize the evolution of population dynamics occurring over a homogeneous tree. We investigate the conditions necessary for these populations to survive, presenting pertinent bounds for survival probability, the number of colonized vertices, the extent of dispersion within the population, and the mean time to extinction for the entire population.