Numerical investigation into the existence of limit cycles in two-dimensional predator–prey systems

There has been a surge of interest in developing and analysing models of interacting species in ecosystems, with specific interest in investigating the existence of limit cycles in systems describing the dynamics of these species. The original Lotka–Volterra model does not possess any limit cycles....

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Main Authors: Quay van der Hoff, Johanna C. Greeff, P. Hendrik Kloppers
Format: Article
Language:English
Published: Academy of Science of South Africa 2013-05-01
Series:South African Journal of Science
Subjects:
Online Access:https://www.sajs.co.za/article/view/3888
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author Quay van der Hoff
Johanna C. Greeff
P. Hendrik Kloppers
author_facet Quay van der Hoff
Johanna C. Greeff
P. Hendrik Kloppers
author_sort Quay van der Hoff
collection DOAJ
description There has been a surge of interest in developing and analysing models of interacting species in ecosystems, with specific interest in investigating the existence of limit cycles in systems describing the dynamics of these species. The original Lotka–Volterra model does not possess any limit cycles. In recent years this model has been modified to take disturbances into consideration and allow populations to return to their original numbers. By introducing logistic growth and a Holling Type II functional response to the traditional Lotka–Volterra-type models, it has been proven analytically that a unique, stable limit cycle exists. These proofs make use of Dulac functions, Liénard equations and invariant regions, relying on theory developed by Poincaré, Poincaré-Bendixson, Dulac and Liénard, and are generally perceived as difficult. Computer algebra systems are ideally suited to apply numerical methods to confirm or refute the analytical findings with respect to the existence of limit cycles in non-linear systems. In this paper a class of predator–prey models of a Gause type is used as the vehicle to illustrate the use of a simple, yet novel numerical algorithm. This algorithm confirms graphically the existence of at least one limit cycle that has analytically been proven to exist. Furthermore, adapted versions of the proposed algorithm may be applied to dynamic systems where it is difficult, if not impossible, to prove analytically the existence of limit cycles.
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spelling doaj.art-27524246841b4749a609999cdcf6a11f2022-12-22T01:57:36ZengAcademy of Science of South AfricaSouth African Journal of Science1996-74892013-05-011095/66610.1590/sajs.2013/11433888Numerical investigation into the existence of limit cycles in two-dimensional predator–prey systemsQuay van der Hoff0Johanna C. Greeff1P. Hendrik Kloppers21 Department of Mathematics and Statistics, Tshwane University of Technology, Pretoria, South Africa 2 Department of Mathematics and Applied Mathematics, University of Pretoria, Pretoria, South AfricaDepartment of Mathematics and Statistics, Tshwane University of Technology, Pretoria, South AfricaDepartment of Mathematics and Statistics, Tshwane University of Technology, Pretoria, South AfricaThere has been a surge of interest in developing and analysing models of interacting species in ecosystems, with specific interest in investigating the existence of limit cycles in systems describing the dynamics of these species. The original Lotka–Volterra model does not possess any limit cycles. In recent years this model has been modified to take disturbances into consideration and allow populations to return to their original numbers. By introducing logistic growth and a Holling Type II functional response to the traditional Lotka–Volterra-type models, it has been proven analytically that a unique, stable limit cycle exists. These proofs make use of Dulac functions, Liénard equations and invariant regions, relying on theory developed by Poincaré, Poincaré-Bendixson, Dulac and Liénard, and are generally perceived as difficult. Computer algebra systems are ideally suited to apply numerical methods to confirm or refute the analytical findings with respect to the existence of limit cycles in non-linear systems. In this paper a class of predator–prey models of a Gause type is used as the vehicle to illustrate the use of a simple, yet novel numerical algorithm. This algorithm confirms graphically the existence of at least one limit cycle that has analytically been proven to exist. Furthermore, adapted versions of the proposed algorithm may be applied to dynamic systems where it is difficult, if not impossible, to prove analytically the existence of limit cycles.https://www.sajs.co.za/article/view/3888Lotka–Volterra modelspredator–prey systemsstable limit cyclePoincaré mappingnumerical method
spellingShingle Quay van der Hoff
Johanna C. Greeff
P. Hendrik Kloppers
Numerical investigation into the existence of limit cycles in two-dimensional predator–prey systems
South African Journal of Science
Lotka–Volterra models
predator–prey systems
stable limit cycle
Poincaré mapping
numerical method
title Numerical investigation into the existence of limit cycles in two-dimensional predator–prey systems
title_full Numerical investigation into the existence of limit cycles in two-dimensional predator–prey systems
title_fullStr Numerical investigation into the existence of limit cycles in two-dimensional predator–prey systems
title_full_unstemmed Numerical investigation into the existence of limit cycles in two-dimensional predator–prey systems
title_short Numerical investigation into the existence of limit cycles in two-dimensional predator–prey systems
title_sort numerical investigation into the existence of limit cycles in two dimensional predator prey systems
topic Lotka–Volterra models
predator–prey systems
stable limit cycle
Poincaré mapping
numerical method
url https://www.sajs.co.za/article/view/3888
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AT johannacgreeff numericalinvestigationintotheexistenceoflimitcyclesintwodimensionalpredatorpreysystems
AT phendrikkloppers numericalinvestigationintotheexistenceoflimitcyclesintwodimensionalpredatorpreysystems