Noise-induced phenomena in the dynamics of groundwater-dependent plant ecosystems with time delay

Abstract

Groundwater-dependent ecosystems may exhibit nonlinear dynamics with bifurcations resulting from feedbacks with water table dynamics. In this paper, by stochastic simulations, the stationary probability distribution and the mean first passage time are investigated in a groundwater-dependent ecosystem under the influences of environmental fluctuations, seasonal rainfall oscillation and time delay. We investigate a variety of noise-induced behaviors affecting regime shifts between ecosystem states. The results indicate that the phenomena of regime shift, noise enhanced stability (NES) and resonant activation (RA) may emerge in the dynamics of phreatophyte vegetation. Moreover, we also show that the direction of regime shifts depends on the time delay and the cross-correlation between noises. The cross-correlation between noises, the time delay, and the periodic force play a significant role on the NES and RA phenomena.