Information entropies and dynamics in the stochastic ecosystem of two competing species

Using the models of stochastic population dynamics, the competitions and interactions of interspecies and between species and the stochastic environment are studied. In this paper, the stochastic ecosystems (in Itô or Statonovich model) of two competing species are investigated through evaluating probability densities and information entropy fluxes and productions of two species. The formulas of entropy flux (i.e. expectation of divergence) and entropy production are educed for numerical calculations, through the corresponding Fokker-Planck equation with its condition and the definition of Shannon entropy. The nonlinear characteristics of entropy fluxes are captured and the relationships are found between the extremal points of entropy productions and the rapid transitions or bifurcations. The numerical results obtained with path integration method show that the probability densities and Shannon entropies of these two stochastic models (in Itô or Statonovich meaning) have the same evolutional tendency but with different points of extrema.