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

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-ari...

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Vydané v:Ecological modelling Ročník 179; číslo 2; s. 153 - 161
Hlavní autori: Stigter, J.D., van Langevelde, F.
Médium: Journal Article Konferenčný príspevok..
Jazyk:English
Vydavateľské údaje: Amsterdam Elsevier B.V 25.11.2004
Elsevier
Predmet:
Animal, plant and microbial ecology
Biological and medical sciences
conservation
ecology
fishery
Fundamental and applied biological sciences. Psychology
General aspects. Techniques
Management of ecosystems
Methods and techniques (sampling, tagging, trapping, modelling...)
Optimal control
policies
populations
Semi-arid grazing systems
Management of ecosystems
Semi-arid grazing systems
Optimal control
Semi arid zone
Ecosystem
Models
Climatic zone
ISSN:0304-3800, 1872-7026
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Popis
Shrnutí: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.
Bibliografia:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:0304-3800
1872-7026
DOI:10.1016/j.ecolmodel.2004.06.003