Stability of Ecosystem Induced by Mutual Interference between Predators

A three-species predator-prey model with Beddington-DeAngelis functional response was established with a food chain including two species of zooplanktons and one of phytoplankton. With nonlinear dynamical theory, the influences of competitions between two zooplanktons and semi-saturation constant on the stability of the system were investigated. Results showed that, in a certain range, increasing competition and saturation constant factor ccould stabilize the ecosystem. We also found that the system only appears Hopf and transcritical bifurcation in a certain range of parameters. Furthermore, the ecological significance of the two bifurcations was presented.