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Titre du document / Document title

Optimal harvesting in a two-species model under critical depensation: The case of optimal harvesting in semi-arid grazing systems

Auteur(s) / Author(s)


Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Systems and Control Group, Wageningen University and Research Center, Bornsesteeg 59, 6708 PD Wageningen, PAYS-BAS
(2) Resource Ecology Group, Wageningen University and Research Center, Bornsesteeg 69, 6708 PD Wageningen, PAYS-BAS

Résumé / Abstract

Ecological systems in general often exhibit the mechanism of critical depensation, i.e. the system may collapse due to decreasing population densities caused by, for example, an increasing predation pressure on the prey that causes both populations to collapse to extinction. In this study a semi-arid predator-prey grazing system is taken as an example and optimal, model based, harvesting rates for the herbivore population are presented that allow survival of both herbivores and grasses during long dry periods without precipitation. Recovery to a maximum sustainable yield is achieved in the next rain season under the assumption of model validity. Optimal control theory is utilized in this example as the principal method of solution. Both analytical and numerical issues of the solution method and obtained solutions are discussed. Survival of the system is possible if the pastoralist is willing to decrease his population considerably once the dry period has set in. The social willingness, necessary to implement these management strategies, can be interpreted in terms of a discount rate in the current value Hamiltonian associated with the dynamical grazing system. The example is worked out in more detail and dynamical solutions for two discount rates are presented.

Revue / Journal Title

Ecological modelling    ISSN  0304-3800   CODEN ECMODT 

Source / Source

Control of Distributed Systems and Environmental Applications. Workshop, Laxenburg , AUTRICHE (05/2003)
2004, vol. 179, no 2 (96 p.)  [Document : 9 p.] (27 ref.), [Notes: Selected papers], pp. 153-161 [9 page(s) (article)]

Langue / Language


Editeur / Publisher

Elsevier, Amsterdam, PAYS-BAS  (1975) (Revue)

Mots-clés anglais / English Keywords

Climatic zone




Semi arid zone




Mots-clés français / French Keywords

Zone climatique




Zone semi aride




Mots-clés espagnols / Spanish Keywords

Zona climática




Zona semiárida




Mots-clés d'auteur / Author Keywords

Optimal control


Management of ecosystems


Semi-arid grazing systems


Localisation / Location

INIST-CNRS, Cote INIST : 15732, 35400012033792.0010

Nº notice refdoc (ud4) : 16127115

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