On the influence of noise on the critical and oscillatory behavior of a predator-prey model: coherent stochastic resonance at the proper frequency of the system

ROZENFELD, A.F.; TESSONE, C.J.; ALBANO, E.V.; WIO, H.S.

PHYSICS LETTERS A

ELSEVIER SCIENCE BV

Año: 2001 vol. 280 p. 45 - 52

0375-9601

Noise-induced changes in the critical and oscillatory behavior of a prey–predator system are studied using power spectrumdensity and spectral amplification factor (SAF) analysis. In the absence of external noise, the population densities exhibit threekinds of asymptotic behavior, namely: absorbing state, fixed point (FP) and an oscillatory regime with a well defined proper(natural) frequency. The addition of noise destabilizes the FP phase inducing a transition to a new OR. Surprisingly, it is foundthat when a periodic signal is added to the control parameter, the system responds robustly, without relevant changes in itsbehavior. Nevertheless, the coherent stochastic resonance phenomenon is found only at the proper frequency. Also, a methodbased on SAF allows us to locate very accurately the transition points between the different regimes.