Research ArticleOpen accessIn the author namesON RESERVES, STABILITY AND THE MAXIMUM SUSTAINABLE YIELD PROBLEMArild WikanDue to the fact that several species of commercial interest have been overexploited throughout the years it is important to understand how harvest and other factors like introducing reserves influence the dynamic behaviour of a population with respect to stability and possible extinction. Therefore, simple one-population models are analysed and it is shown that harvest acts in a strong stabilizing … …Journal of Mathematics and Statistics, Vol. 9, Issue 4 · 24 Oct 2013 · 6,820 accessesView PDFCite
Research ArticleOpen accessIn the author namesTowards Some General Ecological PrinciplesArild WikanDiscrete deterministic age-structured, stage-structured and difference delay equation population models are analysed and compared with respect to stability and nonstationary behaviour. All three models show that species with iteroparous life histories tend to be more stable than species with semelparous life histories which allow us to conclude that this must be a fairly general ecological principle. Considering iteroparity, the precocious … …Journal of Mathematics and Statistics, Vol. 8, Issue 4 · 3 Jan 2013 · 6,931 accessesView PDFCite
Research ArticleOpen accessIn the author namesOn Nonlinear Age- and Stage-Structured Population ModelsArild WikanThe scope of this review article is to present and discuss various aspects of discrete nonlinear age- and stage-structured population models. We show that such models cover species which exhibit a wide range of different life histories and that one may use them in order to deduce fairly general ecological principles with respect to stability and dynamical outcomes. From a … …Journal of Mathematics and Statistics, Vol. 8, Issue 2 · 6 Jul 2012 · 7,057 accessesView PDFCite