Dispersal-induced growth in a time-periodic environment

TL;DR

This paper mathematically investigates dispersal-induced growth (DIG), a phenomenon where two populations with declining growth rates can persist and grow when dispersal is present, especially in environments with periodic changes.

Contribution

It provides a deterministic, mathematical analysis of DIG in periodic environments, identifying key factors and conditions for its occurrence.

Findings

DIG enables persistence of populations with negative growth rates when dispersal occurs.

Periodic variation in growth rates influences the conditions for DIG.

The study characterizes parameter regimes where DIG is possible.

Abstract

Dispersal-induced growth (DIG) occurs when two populations with time-varying growth rates, each of which, when isolated, would become extinct, are able to persist and grow exponentially when dispersal among the two populations is present. This work provides a mathematical exploration of this surprising phenomenon, in the context of a deterministic model with periodic variation of growth rates, and characterizes the factors which are important in generating the DIG effect and the corresponding conditions on the parameters involved.