Impact of time delays on stochastic resonance in an ecological system describing vegetation

•We investigate stochastic resonance (SR) in a vegetation ecological system with time delay.•Time delay and correlation strength enhance SR in SNR versus intrinsic noise strength.•Time delay and correlation strength weaken SR in SNR versus extrinsic noise strength.•Time delay leads to double SR in SNR versus correlation strength.

In this paper, we investigate the stochastic resonance phenomenon in a vegetation ecological system with time delay, at which the vegetation dynamics is assumed to be disturbed by both intrinsic and extrinsic noises. The signal-to-noise ratio is calculated when a weak periodic signal is added to the system. The impacts of time delay ττ and correlation strength kk between two noises on the signal-to-noise ratio are discussed, respectively. Our research results show that: (i) the increase of ττ or kk can enhance the stochastic resonance in the signal-to-noise ratio as a function of intrinsic noise strength αα; (ii) on the contrary, the increase of ττ or kk can weaken the stochastic resonance in the signal-to-noise ratio as a function of extrinsic noise strength DD; and (iii) the increase of ττ can lead to double stochastic resonance phenomenon in the signal-to-noise ratio as a function of kk.