The effects of weak and strong advection on the dynamics of reaction-diffusion models have long been studied. In contrast, the role of intermediate advection remains poorly understood. For example, concentration phenomena can occur when advection is strong, providing a mechanism for the coexistence of multiple populations, in contrast with the situation of weak advection where coexistence may not be possible. The transition of the dynamics from weak to strong advection is generally difficult to determine. In this work the authors consider a mathematical model of two competing populations in a spatially varying but temporally constant environment, where both species have the same population dynamics but different dispersal strategies: one species adopts random dispersal, while the dispersal strategy for the other species is a combination of random dispersal and advection upward along the resource gradient. For any given diffusion rates the authors consider the bifurcation diagram of positive steady states by using the advection rate as the bifurcation parameter. This approach enables the authors to capture the change of dynamics from weak advection to strong advection. The authors determine three different types of bifurcation diagrams, depending on the difference of diffusion rates. Some exact multiplicity results about bifurcation points are also presented. The authors' results can unify some previous work and, as a case study about the role of advection, also contribute to the understanding of intermediate (relative to diffusion) advection in reaction-diffusion models.
Rescigno , A. and Richardson , I. ( 1967 ) Struggle for life 1 : two species , Bulletin of Mathematical Biophysics , 29 , 377-88 . Richardson , H.W. ( 1975 - A ) Two disequilibrium models of regional growth , in Cripps , E.L. ( Ed ...
Applications of Bifurcation Theory: Proceedings of an Advanced Seminar
We write p, Y instead of p7, Y ~ for brevity. Let wo-A-(U00 o'e). geTi For Y and |a| sufficiently small, Wye O B is the graph of a smooth map: tly,s : Tl X B' – B", t'0.2 = Us. This is the extra assumption on the choice of a mentioned ...
Alan Wilson surveys the range of applications currently devised that have been developed from new advances in mathematics enabling the development of models where sudden changes in equilibrium can be accounted for.
Dynamical systems.
Nonlinear Oscillations, Dynamical Systems, and Bifurcations of Vector Fields
The concept of thickness assigns to every Cantor set in the real line a number from 0 to [infinity symbol].
Progress in Partial Differential Equations: Elliptic and parabolic problems