Survival and extinction results for a patch model with sexual reproduction

TL;DR

This paper analyzes a spatially structured sexual reproduction model in metapopulations, showing that survival depends on dispersal range, with intermediate dispersal favoring persistence due to a strong Allee effect.

Contribution

It introduces a patch model with sexual reproduction and demonstrates how dispersal range influences survival, highlighting the role of the Allee effect unlike in basic contact processes.

Findings

Survival probability is high with intermediate dispersal ranges.

Long-range dispersal tends to lead to extinction.

The model reveals a strong Allee effect impacting population dynamics.

Abstract

This article is concerned with a version of the contact process with sexual reproduction on a graph with two levels of interactions modeling metapopulations. The population is spatially distributed into patches and offspring are produced in each patch at a rate proportional to the number of pairs of individuals in the patch (sexual reproduction) rather than simply the number of individuals as in the basic contact process. Offspring produced at a given patch either stay in their parents' patch or are sent to a nearby patch with some fixed probabilities. Specifically, we prove lower and upper bounds for the probability of long-term survival for the process starting with a single fully occupied patch. Our main finding is that, with probability close to one and for a certain set of parameters, the metapopulation survives in the presence of nearest neighbor interactions while it dies out in the presence of long range interactions, suggesting that the best strategy for the population to expand in space is to use intermediate dispersal ranges. This result is due to the presence of a so-called strong Allee effect induced by the birth mechanism and does not hold for the basic contact process.