this paper investigates the dynamics and stability properties of a discrete-time lotka-volterra type system. we first analyze stability of the fixed points and the existence of local bifurcations. our analysis shows the presence of rich variety of local bifurcations, namely, stable fixed points; in which population numbers remain constant, periodic cycles; in which population numbers oscillate amo...

The population growth rate, or intrinsic rate of increase, is the rate of growth that will be achieved by a population with fixed vital rates. The sensitivity of population growth rate to changes in the vital rates can be written in terms of the stable stage or age distribution and the reproductive value distribution. If the vital rate measures the rate of production of one type of individual b...

The evolution of population dynamics in a stochastic environment is analysed under a general form of density-dependence with genetic variation in r and K, the intrinsic rate of increase and carrying capacity in the average environment, and in sigma(e)(2), the environmental variance of population growth rate. The continuous-time model assumes a large population size and a stationary distribution...

We study the qualitative properties of degenerate diiusion equations used to describe dispersal processes in population dynamics. For systems of interacting populations, the forms of the diiusion models used determine if the population will intermix or remain disjoint (segregated). The dynamics and stability of segregation boundaries between competing populations is analyzed. General population...

Population movements are necessary to survive the individuals in many cases and depend on available resources, good habitat, global warming, climate change, supporting environment, other issues. This study explores spatiotemporal effect dynamics of reaction-diffusion model for two interacting populations a heterogeneous habitat. Both species assumed compete different fundamental diffusion strat...

population dynamics of three main alfalfa aphids, namely: pea aphid, acyrthosiphon pisum (harris), spotted alfalfa aphid, therioaphis trifolii forma maculata (buckton), black alfalfa aphid, aphis craccivora koch, and their most abundant predators and parasitoids in three sites and in two subsequent years in isfahan, iran, were investigated. the results revealed that frequency and temporal occur...