title: Food chain chaos due to transcritical point.
abstract: Chaotic dynamics of a classical prey-predator-superpredator ecological model are considered. Although much is known about the behavior of the model numerically, very few results have been proven analytically. A new analytical result is obtained. It is demonstrated that there exists a subset on which a singular Poincare map generated by the model is conjugate to the shift map on two symbols. The existence of such a Poincare map is due to two conditions: the assumption that each species has its own time scale ranging from fast for the prey to slow for the superpredator, and the existence of transcritical points, leading to the classical mathematical phenomenon of Pontryagin's delay of loss of stability. This chaos generating mechanism is new, neither suspected in abstract form nor recognized in numerical experiments in the literature.
authors.affiliation: Department of Mathematics and Statistics, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA. bdeng@math.unl.edu
authors.forename: Bo
authors.initials: B
authors.lastname: Deng
authors.forename: Gwendolen
authors.initials: G
authors.lastname: Hines
mesh_terms: D003198:Computer Simulation; D017753:Ecosystem; D020387:Food Chain; D008954:Models, Biological; D017711:Nonlinear Dynamics; D011157:Population Dynamics; D012680:Sensitivity and Specificity