Bifurcation Patterns and Chaos Control in Discrete-Time Coral Reef Model

Abstract: The reduction in coral reef densities, characterized by the proliferation of macroalgae, has emerged as a global threat. In this paper, we present a discrete-time coral reef dynamical model that incorporates macroalgae. We explore all ecologically possible equilibrium points for the proposed model. The conditions for the local stability of the interior equilibrium point are analyzed, which represents the coexistence of both coral and macroalgae. Furthermore, we investigate the model's behavior using the center manifold theorem and bifurcation theory. Our analysis reveals that the model undergoes codimension-one bifurcations, specifically period-doubling and Neimark-Sacker bifurcations. To address the chaos resulting from the emergence of the Neimark-Sacker bifurcation, we apply the OGY feedback control method and a hybrid control methodology. Finally, we provide numerical simulations not only to validate the obtained results but also to demonstrate the complex dynamic behaviors that arise. These behaviors include reversal period-doubling bifurcation, period-4, 8, and 24 bubble bifurcations, as well as chaotic behavior.