Modeling The Refuge Effect Of Submerged Macrophytes In The Aquatic Ecosystems

In this paper, we establish a model which regards the interaction among phytoplankton, zooplankton, macrophyte and fish. The functional response in our model is Beddington-DeAngelis functional response. We analysis the existence and the local stability of equilibria by means of qualitative theoretical analysis, and study the refuge effect of macrophyte on the zooplankton with numerical simulations in the aquatic ecosystems. At last, we discuss the effective methods of biology control to restrain the increase of the phy-toplankton. The study depicts our model could generates richer, more complex dynamics, such as bistable phenomenon and chaotic phenomenon. Numerical simulation results demonstrate that the refuge constant and the density of the macrophytes are both the key factors which make the refuge effect occur. In addition, the intraspecific competiton between the macrophyte and the phytoplankton also affect the macrophyte’s refuge effect. As showed in our paper, macrophytes provide structure and shelter against predation for zoo-plankton to restore the zooplankton population, and then planting the macrophyte properly might reach the purpose to control algae growth.