RESUMO
We present a mathematical model of an aquatic community, where the size-and-age structure of hydrobiont populations is taken into account and the corresponding trophic interactions between zooplankton, peaceful fish and predatory fish are described. We show that the interactions between separate components of the aquatic community can lead to long-period oscillations in fish population size. The period of these oscillations is of the order of dozen years. With the use of the model we show also that an increase in the zooplankton growth rate can be followed by a set of the fish population dynamical bifurcations: stationary states --> regular oscillations --> quasicycles --> the dynamical chaos.
Assuntos
Peixes , Modelos Teóricos , Densidade Demográfica , Animais , Relógios Biológicos , Ecossistema , Peixes/genética , Peixes/crescimento & desenvolvimento , Zooplâncton/crescimento & desenvolvimentoRESUMO
In this article, we use mathematical modeling to study the impact of population dynamics on Y-chromosome STR-polymorphism accumulation in two independently evolving populations, namely, on the changes in genetic distance among the populations. Using two definitions of the genetic distance: (deltamu)2 and ASD, we carry out comparative research on the genetic distance changes and show that in contrast to (deltamu)2, ASD is characterized by a near-linear dependence on time. As the populations undergo oscillations, ASD is shown to be smaller than that in stationary populations. The linear dependence of ASD on time is shown to break down in relatively scanty stationary populations.
Assuntos
Cromossomos Humanos Y/genética , Repetições de Microssatélites , Modelos Genéticos , Evolução Molecular , Feminino , Deriva Genética , Humanos , Masculino , Polimorfismo GenéticoRESUMO
With the use of recurrence plots, we show that the irregular oscillations in time, which commercial fish populations in Lake Peipus undergo, are deterministic.
Assuntos
Modelos Estatísticos , Reprodução/fisiologia , Animais , Pesqueiros , Peixes , Lagos , Computação Matemática , Densidade Demográfica , Dinâmica Populacional , Projetos de Pesquisa , Federação RussaRESUMO
We present a mathematical model of the invasion of mysid into the Naroch Lake system. The model is parameterized with the use of field observation data. We show that the mysid invasion can lead to an increase in the time-averaged fish population size, and to a decrease in the time-averaged rotifer population size.
Assuntos
Crustáceos/fisiologia , Ecossistema , Espécies Introduzidas , Modelos Biológicos , Animais , Água Doce , Densidade Demográfica , República de BelarusRESUMO
A conceptual mathematical model of fish and zooplankton (rotifer) populations inhabiting the lakes Naroch and Myastro has been developed and studied. The parametrization of the model was carried out having regard to the field observation data. The population dynamics was simulated taking into account that the lakes Naroch and Myastro are coupled with each other by a channel. It was shown that both the population coupling and trophic interactions result in regular and irregular oscillations of the population size.
