The competitive dynamics of populations subject to an Allee effect

The Allee effect is introduced into intraspecific and two-species competiti ve models. We use phase plane analysis and simulation to investigate the dy namics of these models. Combining simple modeling and simulations, we demon strate that the Allee effect alone could lead to alternative stable states in two-species competitive systems. In such systems, if interspecific compe tition is intense, both species may go extinct even if their population den sities are high. Compared to a Lotka-Volterra competitive system, systems i ncluding Allee effect show obvious destabilization. (C) 1999 Elsevier Scien ce B.V. All rights reserved.