J. Ylikarjula

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The effect of red, white and blue environmental noise on discrete-time population dynamics is analyzed. The coloured noise is superimposed on Moran-Ricker and Maynard Smith dynamics, the resulting power spectra are less than examined. Time series dominated by short- and long-term fluctuations are said to be blue and red, respectively. In the stable range of(More)
Dwarf individuals are observed in many species of freshwater fish. This paper studies the potential causes of such stunted growth. We present a model which describes the effect of growth conditions on the age- and size-structure of fish populations. The model parameters are chosen to characterize a Eurasian perch population. Two possible causes of stunting(More)
In this paper, we examine the effects of patch number and different dispersal patterns on dynamics of local populations and on the level of synchrony between them. Local population renewal is governed by the Ricker model and we also consider asymmetrical dispersal as well as the presence of environmental heterogeneity. Our results show that both population(More)
1) Systems Analysis Laboratory, Helsinki University of Technology, P.O. Box 1100, FIN-02015 HUT, Finland 2) Department of Ecology and Systematics, University of Helsinki, P.O. Box 17, FIN-00014 University of Helsinki, Finland 3) Adaptive Dynamics Network, International Institute for Applied Systems Analysis, A-2361 Laxenburg, Austria 4) Department of(More)
In this paper we examine the e ects of di erent dispersal patterns on the dynamics of two and a larger number of coupled populations and on the level of synchrony in local population dynamics. In these systems local population renewal is governed by the Ricker model, which is characterized by a single parameter, the intrinsic rate of increase r. Dispersal(More)
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