Untangling the role of temporal and spatial variations in persistance of populations

Fuente: arXiv
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Autori principali: Benaïm, Michel, Lobry, Claude, Sari, Tewfik, Strickler, Edouard
Natura: Preprint
Pubblicazione: 2021
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author Benaïm, Michel
Lobry, Claude
Sari, Tewfik
Strickler, Edouard
author_facet Benaïm, Michel
Lobry, Claude
Sari, Tewfik
Strickler, Edouard
contents We consider a population distributed between two habitats, in each of which it experiences a growth rate that switches periodically between two values, $1- \varepsilon > 0$ or $ - (1 + \varepsilon) < 0$. We study the specific case where the growth rate is positive in one habitat and negative in the other one for the first half of the period, and conversely for the second half of the period, that we refer as the $(\pm 1)$ model. In the absence of migration, the population goes to $0$ exponentially fast in each environment. In this paper, we show that, when the period is sufficiently large, a small dispersal between the two patches is able to produce a very high positive exponential growth rate for the whole population, a phenomena called inflation. We prove in particular that the threshold of the dispersal rate at which the inflation appears is exponentially small with the period. We show that inflation is robust to random perturbation, by considering a model where the values of the growth rate in each patch are switched at random times: we prove, using theory of Piecewise Deterministic Markov Processes (PDMP) that inflation occurs for low switching rate and small dispersal. Finally, we provide some extensions to more complicated models, especially epidemiological and density dependent models.
format Preprint
id arxiv_https___arxiv_org_abs_2111_12633
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Untangling the role of temporal and spatial variations in persistance of populations
Benaïm, Michel
Lobry, Claude
Sari, Tewfik
Strickler, Edouard
Dynamical Systems
Probability
Populations and Evolution
We consider a population distributed between two habitats, in each of which it experiences a growth rate that switches periodically between two values, $1- \varepsilon > 0$ or $ - (1 + \varepsilon) < 0$. We study the specific case where the growth rate is positive in one habitat and negative in the other one for the first half of the period, and conversely for the second half of the period, that we refer as the $(\pm 1)$ model. In the absence of migration, the population goes to $0$ exponentially fast in each environment. In this paper, we show that, when the period is sufficiently large, a small dispersal between the two patches is able to produce a very high positive exponential growth rate for the whole population, a phenomena called inflation. We prove in particular that the threshold of the dispersal rate at which the inflation appears is exponentially small with the period. We show that inflation is robust to random perturbation, by considering a model where the values of the growth rate in each patch are switched at random times: we prove, using theory of Piecewise Deterministic Markov Processes (PDMP) that inflation occurs for low switching rate and small dispersal. Finally, we provide some extensions to more complicated models, especially epidemiological and density dependent models.
title Untangling the role of temporal and spatial variations in persistance of populations
topic Dynamical Systems
Probability
Populations and Evolution
url https://arxiv.org/abs/2111.12633